Brain Sailing

2011-02-08T11:36:00.016Z

One frequent criticism of psychological research is that much of it is inconsequential. That it produces little more than 'cool' illusions which, although illuminating how are minds work, are little more than party games. Often this may be true, but it neglects to see the influence such illusions have on wider science.

Take for example, the rubber hand illusion. This appears, on the face of it, as little more than a clever psychological trick, a clever illusion that has little merit above its novelty value.

The illusion consists of a subject sitting at a table, with one arm placed on the surface in front of them and the other obscured from view. In its place, a rubber hand is placed, which may be somehow connected to them via a fake sleeve, to make the illusion more convincing. Here is an example of how the setup looks.

The experimenter then begins to either tap or stroke the rubber hand, while simultaneously doing the same motion to the real hand in synchrony, which remains out of sight of the subject. After a few minutes of synchronised stroking of the artificial and the hidden hand, the subject should begin to associate the artificial hand as their own. This occurs to such an extent that even after the experimenter stops stroking the real hand, the subject still 'feels' the sensation when the rubber hand is stroked.

Watch the rubber hand illusion

When people see this illusion, it can be quite fascinating and certainly a novelty, and is probably quite eery for the subject. A skeptic, however, may question the practical application of such an illusion, and then no doubt begin to harp on the money being wasted in social science research.

However, an interesting new piece of research caught my eye, and I feel it highlights exactly how clever trickery such as this can influence other fields of research.

The research, described here, involves attaching a prosthetic arm to an amputee. The remaining nerve endings, which had previously projected to parts of the missing limb, are rerouted to a patch of skin on the remaining portion amputated arm, via a process called reinnervation. Stimulating different parts of this patch of skin will create the impression that the amputee is being touched on various parts of their missing arm.

Where this becomes clever, and where the influence of the rubber hand illusion comes in, is in the design of the prosthetic arm. The prosthesis is fitted with an intricate system of pressure sensors, which communicate with a 'robot' in contact with the innervated patch of skin. When the prosthetic arm is touched, it in turn stimulated the nerve endings which would have corresponded to that part of the amputated arm. So, for example, if the prosthetic arm detects pressure on the thumb, this is relayed to the nerves which previously projected to the real thumb, which are now situated in the proxy patch of nerve endings.

As with the rubber hand illusion, the brain quickly begins to adopt the prosthetic arm as part of the body. However, unlike the rubber hand illusion, the prosthesis can be used by the amputee to carry out the tasks that you and I take for granted, such as manipulating objects, hold and carrying items, and presumably if this technology becomes more sensitive in the future, can become increasingly sensitive to touch.

In future, this technology could be combined with other revolutionary technology, such as other new prostheses that can be connected directly to the brain, as described here. Although each technology is in its infancy, we could be very close to the ability to replace missing limbs with new ones which are naturally controlled by the brain, and retain the sensitivity to touch, as with the real thing.

Next time, then, you hear somebody dismiss a bit of psychological research as a novelty, or as a clever but useless trick, spare a thought for the influence this may have on other fields of research.

2011-01-27T09:18:00.002Z

Hello!

You might be wondering where I've been. Well, so am I.

Last time I wrote on these pages I had just handed in my thesis, and in doing so, completed my masters. It turns out that I did rather well, and ended up passing with distinction, which was a wonderful surprise. My former supervisor and I are looking to submit our results to a journal for publication, and I shall keep you posted on our progress. It will be my first publication, and so the whole process of submission, peer review and revision is as alien to me as it probably is to you.

Next up is the PhD application process, which will of course be hugely fun. I have already applied for a couple, and already had one rejection. I am not too disheartened, though, because the one that rejected me was, for neuroscience, the cream of the crop, and massively competitive. When I, eventually, get accepted onto a programme, I will be sure to chronicle my experiences here, hopefully a little better than I did on my masters.

I shall leave you with a little reading material, that hopefully you will find enthralling. The royal society recently published a series of articles on neuroscience, with topics ranging from the technical methods by which neuroimaging works, to some of the ethical quandaries of studying brain function. The whole selection can be found here.

One article that I found particularly accessible for a non-scientific audience was 'The scope and limits of neuroimaging' by Professor Geraint Rees (director of the UCL Institute of Cognitive Neuroscience, where I researched my thesis). It gives a great introduction to some of the key themes of my masters course, namely the various different methods used to image the brain, their strengths and their weaknesses. The article can be found here.

Anyway, that is enough from me. I'll be in touch.

Finished...

2010-08-28T12:08:00.001+01:00

At about 4pm on Friday the 20th of August, if you were anywhere in the vicinity of central London, you may have noticed an audible collective gasp; a long and satisfied expulsion of anxious tension. This was the moment that my masters drew to a close, as each and every student on the course handed over their thesis, the fruits of nine months hard slog, before promptly retiring to either the pub, or to bed. In my case, the latter was my chosen option, having spent the entire previous evening, night, morning and afternoon tweaking, redrafting, and desperately trying to get the darn thing printed in time. I did, with five minutes to spare.

In the end, I think I turned in a really good piece of work. I hope so. It has certainly had a lot of praise from the two individuals who will be marking my work, which can only be a good sign. As an extra bonus, it looks likely to be published in a peer-reviewed academic journal, which will be a huge boost to my fledgling career.

Essentially, our project set out to examine what happens when a specific sound becomes behaviourally important. Numerous studies on animals have shown that when a target frequency is paired with an electric shock (to make it behaviourally significant) the area of the brain which ‘looks out’ for that sound gets bigger. What isn’t understood is how this affects the ability to perceive that tone.

We paired a target frequency with a shock, like the animal studies, and participants had to discriminate between the target frequency and other frequencies, some very close and some much further from the target. If, as the animal studies suggest, this leads to an expansion of the target representation on the cortex, will the participants get better at telling the target frequency from tones that are very very close to the target?

The answer, is yes. When subjects were being conditioned with the shock, they became much better at telling apart tones that were very close in frequency. This effect happened rapidly, and did not occur when participants were not being conditioned.

The neuroimaging results also indicated that there was greater brain activity in response to the frequency that was paired with the shock, compared to all other tones. This would fit with the expanded representation demonstrated in the animal studies.

So what? What does all this mean? Well, firstly, we have demonstrated that the human brain begins to adapt and change to our environment within minutes, something that would have been inconceivable a few years ago. Secondly, studies like ours help us to understand the basics of more complex mechanisms, which future studies will elucidate further. How does early musical training produce a child genius? How are our sensory memories stored, and what does this tell us about memory as a whole? What are the limits of the brains ability to change itself, and how can we use this information to treat brain damage or stroke? All these bigger questions will need a basic foundation to expand upon, and studies like ours, which may in isolation appear trivial, can provide the basis for these foundations.

Finally, some rest.

2010-05-16T13:09:00.002+01:00

Lectures - finished.

Coursework - completed.

By pure chance, it turns out that my research project supervisor is out of the country this week, the week immediately after my final coursework assignment was handed in, meaning that I have had an entire week with absolutely nothing to do. It has been total bliss.

Starting on Tuesday we should hopefully be in a position to start the research. Initially we will pilot the equipment on ourselves, in order to check everything is in working order. Then we go live and begin testing our participants, and we are hoping to complete the bulk of the research in two or three weeks, provided we can keep a steady stream of particpants coming in and out of the lab.

Obviously I shall keep you up to date with our progress!

2010-04-27T12:24:00.003+01:00

I have noticed a worrying trend in my academic career - they always leave things on a downer.

My last lecture on the MSc was on the subject of depression.

When I did my undergraduate degree, our final module was on the psychology of ageing, which was structured in a chronological way so that we ended up covering the cheery topic "bereavement, loneliness and dying".

My final essay topic for the MSc? "Has research into the biological basis of depression had any impact on its treatment?"

Hmm, am I subtly being set-up for a lifetime of professional disappointment?

Oscillations

2010-04-20T15:12:00.003+01:00

I am currently attempting to steer myself through the penultimate essay on my MSc course, which unfortunately is proving to be without a doubt the hardest essay I have ever had to write.

It's about 'the functional role of brain oscillations', and is quite interesting at the same time as being obscenely dull. Essentially, I am writing about how there has always been a bias toward examining where in the brain things are processed, but now there is loads of evidence to suggest that observing when the brain works it's magic are just as essential.

It turns out that brain cells oscillate - the electrical activity they display is not random, it has a rhythm. Nothing particularly remarkable about that, but huge numbers of brain cells actually oscillate together - they become synchronised in their activity, and are extremely accurate (to under a millisecond).

To complicate matters, the frequency at which they oscillate, the speed of the rhythm, varies across different parts of the brain, and also varies for different activities. So we have clusters of cells all 'wobbling' together, at a certain frequency, and other clusters all doing the same at a different frequency.

These oscillations are the brain waves you may have seen on TV, when people are made to do experiments wearing funny electrodes on their head, which produces squiggly lines on a monitor.

So, as I said - the timing of brain activity is equally as valid a field of study as the physical layout of the brain. Neuroscientists are easily seduced by fancy looking brain images, and this may go some way to explain the bias towards the where, but this has meant out knowledge of the when is now lagging behind.

Anyway, its horrifically complicated in places, and the afore mentioned bias in the research means its patchy and inconsistent, and this essay is proving to be a real challenge. But then, I knowingly chose what I thought was the hardest question, as it is potentially the one that may be of must use to me in my future research, so I think I made the right decision in picking this essay.

Still, another 1,500 words to write by Friday, and I stupidly signed up for a two day course starting on thursday...

Better get oscillating!

Nearly there....

2010-04-07T14:08:00.001+01:00

Coursework deadlines:

MODULE	EXAMINATION	DEADLINE/DATE
~~Introduction to cognitive neuroscience~~	~~2,000-3,000 word written essay~~	~~12 February 2010~~
~~Structure and measurement of the human brain~~	~~2-hour unseen written exam~~	~~15 January 2010~~
~~Experimental design and statistics~~	~~Coursework~~	~~Announced in class~~
~~Methods I: lesion approaches~~	~~Two 1,000-1,500 word written reports~~	~~Report 1: 18 December 2009~~ ~~Report 2: 12 February 2010~~
~~Methods II: neuroimaging~~	~~Two 1,000-1,500 word written reports~~	~~Report 1: 26 March 2010~~ ~~Report 2: 9 April 2010~~
Current issues I: fundamental processes	2,000-3,000 word written essay	9 April 2010
Current issues II: elaborative and adaptive processes	2,000-3,000 word written essay	23 April 2010
Current issues III: translational research	2,000-3,000 word written essay	7 May 2010
Research project	10,000-12,000 word written dissertation	20 August 2010

2010-03-26T16:51:00.003Z

I recently had to write a mini essay on how the mainstream press might misrepresent data from neuroimaging studies, such as functional magnetic resonance imaging (fMRI). I thought that, given the nature of the question, it might be a good thing to put up on my blog, so here it is, with a few tweaks and extra explanations of some of the terminology thrown in along the way.

How might fMRI data be misrepresented in news articles targeted to the general
public?

Like many complex disciplines, cognitive neuroscience is plagued by misrepresentation in the media. Most journalists lack the skills, or the integrity, to identify reputable sources of research, and there is a tendency to sensationalise and exaggerate the significance of research, which falsely presents findings as a series of epoch-defining breakthroughs, which is a fundamental misunderstanding of the aggregate nature of scientific advancement. Additionally, the mainstream media reports research in isolation, detached from the context of a theoretical framework. The journalist may cite a few key comments from the author, falsely presenting scientists as infallible authority figures. Often, in an attempt to provide balance, a dissenting voice from an opposing scholar is also presented, making science appear to the public as a series of contradictory, diametrically opposed irrelevancies.

These are generic flaws of pseudoscientific journalism, whereas cognitive neuroscience is specifically vulnerable to misrepresentation. This is because it is is a field in which the public has a great interest, but very little knowledge. This enthusiasm for neuroimaging is understandable, as cognitive neuroscience examines intrinsically human topics, such as consciousness, personality, and emotion. Because of the perceived impenetrability of the brain in the public consciousness there is a tacit belief that this research is utterly incomprehensible, leading to ready acceptance of the press reports without critical appraisal. For example, research has shown that presenting an image of a brain in an article will make the scientific credibility of the research appear greater to the reader (McCabe & Castel, 2008). A similar effect has been demonstrated when neuroscientific terminology is inserted into an article, even when it bears little relevance to the discussion (Weisberg, Keil, Goodstein, Rawson, & Gray, 2008). Clearly, this mystification of brain function amongst the public is open to abuse, deliberate or unintentional.

Reports of fMRI in the press tend to be overly optimistic about its potential, fail to explain its limitations, and are not sufficiently critical of the methodology (Racine, Bar-Ilan, & Illes, 2005). This problem is exacerbated by the contention that much fMRI data has already been distorted and excagerated by the researcher, knowingly or otherwise (Vul, Harris, Winkielman, & Pashler, 2009). This means that the general public, who are untrained in how to critically appraise neuroscientific research, are often presented with news reports which bear little resemblance to the true results.

(At this point, I will interject to remind you about the difference between forward and reverse inferences. A forward inference is when the researcher plots in advance what brain activation they expect to see when a person does a given task in the scanner. This might be as simple as "the participant will do a language task, so we expect to see the left posterior section of the superior temporal gyrus activated, because this is where we process and understand language". This kind of inference is not perfect, but it is better than the alternative, because we are making and testing a prediction.

The alternative, the reverse inference, is severely frowned upon in cognitive neuroscience. Imagine we did the experiment I just described, and as well as activation in the superior temporal gyrus we also saw activation in several other areas which we were not expecting to be activated. We could not then start to speculate on why these other areas were activated, because brain areas often have more than one function, so guess work is considered very bad science indeed. With that little aside out of the way, you should all be able to follow my next point!)

Additionally, the fallacy of reverse inference, avoided by credible neuroscientists, still appears viable to laypeople, especially given the popular myth that we humans only use 10% of our brain (this is not true - every part of the brain has a known function). This myth masks the complex and multipurpose nature of brain function, supporting the notion that brain activity is easily attributable to specific cognitive functions.

Racine, Bar-Ilan, and Illes (2005) examined the portrayal of fMRI research in the media, and identified three key trends, “‘neuro-realism’, ‘neuro-essentialism’ and ‘neuro-policy’” (p. 2). Neuro-realism, they claim, is the phenomenon whereby subjective findings falsely appear as objective fact when viewed within the context of a neuroimaging study. The second, neuro-essentialism, describes the tendency to attribute a self or personality to the brain itself, almost to the point where the brain is depicted as being self-aware, admonishing the individual from any degree of control. Finally, neuro-policy is the politicisation of neuroscientific research to fit and reinforce a social or political agenda. Taken as a whole, these trends misrepresent the findings and usage of fMRI in cognitive neuroscience, ignoring its true purpose as a scientific tool to devise and test hypotheses, and to detail the true workings of the mind and brain.

References

McCabe, D. P., & Castel, A. D. (2008) Seeing is believing: The effect of brain images on judgments of scientific reasoning. Cognition, 107, 343-352.

Racine, E., Bar-Ilan, O., & Illes, J. (2005). fMRI in the public eye. Nature Reviews Neuroscience, 6(2), 159-164.

Vul, E., Harris, C., Winkielman, P., & Pashler, H. (2009). Puzzlingly high correlations in fMRI studies of emotion, personality, and social cognition. Perspectives on Psychological Science, 4(3), 274-290.

Weisberg, D. S., Keil, F. C., Goodstein, J., Rawson, E., & Gray, J. R. (2008). The seductive allure of neuroscience explanations. Journal of Cognitive Neuroscience, 20(3), 470-477.

There you go, I hope you will all now be a little more sceptical next time you see an astonishing revelation about the brain on the news or in the paper!

Just one more thing...

2010-03-23T11:37:00.003Z

When I said after lectures finish it was just the research project to work on, I neglected to mention:

A 1,500 word critical analysis of a neuroimaging paper due on Friday,
A 1,500 word essay due on April 9th.
A 2,000 - 3,000 word essay also due on April 9th.
A 2,000 - 3,000 word essay due on April 23rd.
Another 2,000 - 3,000 word essay due on May 7th.

I think I shall be a busy boy over the coming weeks.

2010-03-17T18:39:00.002Z

There was quite an interesting programme on BBC radio 4 the other day about the rights and wrongs of some of the practical applications of neuroscience technology.

And now, the end is near...

2010-03-16T13:30:00.004Z

Somewhat unbelievably, we are now in the last 2 weeks of formal lectures, although as usual there is still an array of optional and supplementary talks going on at the various affiliated institutions. However, the taught aspect of the MSc is now all but over. This leaves only the prospect of the research project looming, lumbering into sight like some gigantic beast from a 1950s B-movie, pulverising anything that dare get in its way.

Tomorrow I meet with my supervisor/collaborator to really get the process started, and we will draw up exactly what will happen, when, and who will be responsible for what.

A few weeks ago I posted here a simplified explanation of our research proposal. I will now attempt to explain, in as accessible a form as possible, what this research has got to do with the real world. But first, a very quick recap of the basics.

The field is auditory psychophysics. At first the name alone was enough to make me want to run for the hills, but it's not half as scary as it sounds. As is so often the case in neuroscience the intimidating nomenclature masks a surprisingly simple concept. Psychophysics, it turns out, is just the study of how the brain processes the information we get from the senses, in this case, sound. Therefore the grand old title 'auditory psychophysics' really just means 'what the brain does with everything you hear'.

There is now a wealth of evidence to suggest that the structure of the brain, i.e. which cells connect with which and how strong the connections are, is constantly changing, and that this change is driven by the importance of the sensory information we receive.

In the case of sound, incoming information is processed mainly in the primary auditory cortex, or A1. I have explained before the concept of tonotopic organisation, but as a little refresher imagine that a little part of the surface of the brain is like the keys of a piano. When you hear a high pitched sound the braincells at the top of the piano are activated, and as the pitch decreases the activity moves further down as the musical pitch gets deeper.

As a result of this type of organisation each cell in A1 has what is termed a best frequency, or BF. This is frequency to which the cells responds the strongest, and as the frequency moves away from the BF the response gets smaller, until there is no response at all.

So, what happens if a certain frequency suddenly becomes very important to your behaviour. For example, consider the sound of a screeching predator, which would be a very good indicator that you should make yourself scarce as soon as possible. It would be very helpful if you processed these behaviourally relevant sounds quicker than irrelevant background sounds.

Well, when a sound like this suddenly becomes very important we find that more of the auditory neurons will change their BF to the frequency in question, making the animal more sensitive to that sound.

It sounds fairly straightforward, but we are talking about a small cluster of cells amongst tens of billions, a great many of which show a similar adaptability for the area to which they are specialised. So this will be going on not just for sound frequency, but also for the other properties of sound, such as volume. Additionally, plasticity has been shown in other domains such as vision, touch and smell. And that is just the senses, our own internal states are also constantly being monitored in a similar fashion.

The bigger picture is one of a brain that is constantly adapting to perform at peak performance in whatever environment it is placed.

This plasticity is greatest in infancy. Babies are born with far more connections between brain cells than are present in adults, perhaps as many as double. This is because most of our adaptation to our environment happens in the first few years of life. Once the infant is adapted to its environment, the irrelevant brain connections are pruned away, remaining if not dead then largely dormant.

This extreme early adaptability has a few intriguing applications. For example, if a human baby is exposed to enough monkey faces early in development it will be able to distinguish monkey faces just as well as human faces (presumably into adulthood), although for an adult this would be almost impossible to learn. Another example of this early adaptability and pruning is seen in the use of language, with babies able to learn all the different vocal intonations seen in languages around the world, even sounds that are almost indistinguishable to Western adults, such as certain African dialects that involve communication through clicks produced in the throat. This potential bilingualism does not last long, and beyond the first couple of years of life we become locked into the grammatical constraints of our first language (which incidentally is the reason that native Japanese speakers find it so hard to distinguish between R and L, a feature of language that is nor present in Japanese).

However, as I said, the connections that are pruned after infancy remain dormant rather than dead, and plasticity experiments suggest that with appropriate training they can be revived to some degree.

Plasticity, therefore, is like Darwinism happening in real time. It takes many generations for a species to physically adapt to their environment, but the clever old brain can do it in a matter of hours.

2010-02-27T13:36:00.002Z

Gosh, it has been quite some time since I last posted an update.

Everyone I talk to on the MSc keeps saying how tired they are feeling, and I am no exception. I find it very hard to concentrate on getting work done, as I am distracted by the prospect of just finishing this course and getting out into the world, finding a decent job and (hopefully) earning a respectable wage for the first time in my life.

Still, I am struggling to stay grounded, to get the work done and my mind on the tasks in hand. I am about to throw myself into this research project. I have hundreds and hundreds of pages I need to read and understand in the coming weeks,and at the moment this task is quite daunting. Ho hum, it must be done.

Oh yeah, and we are just about to be set our final batch of coursework, and I should hopefully get my marks for that exam I had in January next week. Keep your fingers crossed for me!

2010-02-15T18:03:00.001Z

A proper post to follow, but in the mean time:

How might historical thinking about relationships between brain and language relate to current theories and interpretation of behavioural and neuroimaging data?

Introduction

There is no single canonical historical perspective on the relationship between brain and language; anecdotal reports of prototypical aphasic conditions were detailed by the ancient Egyptians, and many contradictory discoveries of dubious veracity emerged over the subsequent millennia. Therefore we shall consider the generally accepted model of the brain and language immediately prior to the twentieth century, shortly before the emergence of neuroscience as a formalised empirical pursuit, as the zenith of historical understanding of the subject, which we shall term the classical model. We then examine how this model relates to the predominant twentieth century assumptions of modularity and functional localisation, and in turn our current understanding of the brain. Finally, we consider what modern neuroscience has taught us that is beyond the technological capabilities of the historical pioneers of language.

The classical model of language

The two main contributors to the classical model of language were Paul Broca and Carl Wernicke, who pioneered our understanding of language production and comprehension respectively (Binder et al., 1997). Broca expanded on a hypothesis posited by his contemporary Jean-Baptiste Bouillaud to propose that the posterior inferior frontal gyrus of the left hemisphere was the region of the brain responsible for language production, based on lesion evidence gathered from his own patients. Wernicke identified that damage to the posterior part of the superior temporal gyrus in the left hemisphere resulted in a receptive aphasia with retained speech production, and postulated that this region was responsible for the memories of words and in turn the comprehension of the speech of others. These discoveries were historically significant in several respects; firstly they identified the left hemisphere as being the predominant hemisphere in language production and processing. Secondly, whilst these discoveries were a major step in the neurological understanding of language, they were even more significant for neuropsychology as a whole, as for the first time they elevated the concept of functional localisation above the pseudoscience of phrenology.
Whilst both Broca and Wernicke undoubtedly made a substantial contribution to our understanding of language, the classical model of language can be challenged in several respects. For example, lesions to the areas described by Broca and Wernicke do not always result in the deficits they described. Furthermore, aphasia of both production and comprehension of language can occur without lesions to the regions outlined in the classical model (Caplan, et al., 2007; Willmes, & Poeck, 1993). These discrepancies suggest that the neural basis of language is far more complex than can be accounted for by the historical model, meaning it must be either expanded or replaced. As a result language is still an intensely scrutinised field in modern neuroscience.

Language in the age of neuroscience

Early imaging studies somewhat supported the classical model of language (Cabeza & Nyberg, 2000), and more recently Broca’s area and the surrounding region have been shown to be active when translating phonemic information into articulatory information in preparation for speech (Papoutsi et al. 2009). The use of transcranial magnetic stimulation (TMS), when applied over Broca’s area in normal patients can temporarily prevent articulate speech, and almost paradoxically, the therapeutic use of TMS, when applied over the right hemispheric Broca’s area has been shown in some cases to improve picture naming in subjects with Broca’s aphasia (Naeser, et al., 2005). This behavioural data implicates Broca’s area in speech production, as the classical model dictates.
Broca was not without his critics, even in his own time, and shortly after Broca’s death the French neurologist Pierre Marie noted that expressive aphasia was not exclusively associated with lesions to Broca’s area, but also with regions such as the insula and the basal ganglia (Marie, 1906, as cited in Dronkers, Plaisant, Iba-Zizen, & Cabanis, 2007). Modern neuroscientists have also identified additional linguistic brain areas, including the thalamus, insula and basal ganglia (Damasio & Geschwind, 1984; Mazzocchi & Vignolo, 1979; Naeser & Helm-Estabrooks, 1985). This posthumous vindication for Marie’s remarkably prescient discovery is also somewhat ironic, as modern MRI studies have since shown significant damage to the insula and the basal ganglia in the preserved brains of Broca’s own patients (Dronkers et al., 2007).
The region commonly known as Wernicke’s area, the posterior superior temporal gyrus, has also been scrutinised by modern neuroscientists, and many have found evidence to support Wernicke’s hypothesis that this region plays a key role in language comprehension (Friederici, Makuuchi, & Bahlmann, 2009). An fMRI study by Grodzinsky and Friederici (2006) found this area to be involved in integration of syntactic and lexical information, crucial in decoding the speech of others. Increased activation of the posterior superior temporal gyrus has also been shown to be correlated with violations of grammatical structures, such as word order (Bornkessel, Zyssett, Friederici, von Cramon, Schlesewsky, 2005; Stowe, et al. 1998) and various other factors associated with the complexity of language comprehension tasks (Friederici, Makuuchi, & Bahlmann, 2009). This appears to support Wernicke’s hypothesis that this region is implicated in syntactic and lexical comprehension.

The modularity debate

The classical model of language was formed largely on the assumption of functional localisation. This theory suggested that specific cognitive faculties are functionally compartmentalised into distinct structures within the brain, and would later become entrenched in cognitive psychology by the likes of Fodor (1983), although many others subscribed to the concept of an integrated brain (Farah, 1994; Uttal, 2003). The modular doctrine has become somewhat challenged in light of advanced neuroimaging techniques, and some have speculated that the modular account of language must be drastically reconsidered, if not abandoned, in the light of modern imaging studies (Bates & Dick, 2000).
Contemporary neuroscientists have now identified a wide variety of structures within the brain that appear to be implemented in language production and processing (Fedorenko & Kanwisher, 2009). Furthermore, and perhaps uncomfortably for proponents of localisation, almost every part of the brain has at some point been prescribed a linguistic function by modern neuroscience (Bates & Dick, 2000). Whilst some of these studies support the classical model, many also flatly contradict it. For example, certain linguistic comprehension processes have been observed in regions independent of Wernicke’s area, including in Broca’s area (Ben-Shachar, Hendler, Kahn, Ben-Bashat, & Grodzinsky, 2003; Bornkessel-Schlesewsky, Schlesewsky, & von Cramon 2009) which would surely cause both of the behemoths of the classical model some distress. However, clear correlations have been observed between left hemispheric lesions and specific patterns of deficits (Cooper, Eichhorn, & Rodnitzky, 2008), therefore one might conclude that while it may be a gross oversimplification, there is almost certainly some specialisation for language in this region, and neither historical nor contemporary science has yet been able to fully explain how these interact with the brain as a whole.

The contributions of modern neuroscience

Contemporary scientific methods have helped to elucidate the linguistic brain in ways that the early pioneers, who could only examine the brain on post-mortem, were unable. Broca’s decision to avoid dissecting his subjects meant he grossly underestimated the extent of their subcortical damage, and the surface lesion had engulfed a far greater area of cortex than he had described (Dronkers et al., 2007), as they included additional parts of the frontal lobe and the lateral and medial prefrontal cortex, now known to also have important linguistic functions (Binder et al., 1997). This also explains why modern patients with lesions confined to Broca’s area often show rapid signs of recovery (Bakheit, Shaw, Carrington, & Griffiths, 2007), whilst Broca’s own patients symptoms continued to deteriorate until death. However, the recovery of modern aphasics also serves to illuminate a phenomenon which none of the historical researchers could have foreseen, neuroplasticity. Modern neuroimaging has revealed the ability of the brain to compensate for damage to many areas, including linguistic regions. For example, in patients with left hemispheric lesions the right hemisphere can often adopt some of the language functions normally associated with the left, and if the patient begins to recover from the aphasia the left hemisphere can begin to regain the lost language functions (Knopman, Rubens, Selnes, Klassen, & Meyer, 1984).
In infants, congenital damage to the left hemisphere does not typically result in aphasic conditions (Bates & Roe, 2001). Damage to the left hemisphere can lead to some developmental delays in language compared to damage to the right hemisphere but after infancy there is no significant difference in language deficit between those with congenital left or right damage (Bates, et al, 1997). Imaging studies have suggested that in cases such as these the right hemisphere can adapt to adopt the language faculties normally observed in the left hemisphere (Feldman, 2005). This strongly supports the assertion that whilst the left hemisphere is by default the predominant language centre of the brain, this is not a concrete configuration and can be developmentally subverted where necessary. Additionally, some linguistic functions have recently been identified in the right hemisphere in the normal population, such as the right homologue to Wernicke’s area, which is thought to process words with ambiguous meaning (Harpaz, Levkovitz, & Lavido, 2009). This has implications for the historical model of language, as it challenges the assertion that the left hemisphere is the categorical language centre of the brain, and in that it suggests that the functional areas described by Broca and Wernicke can be circumvented.
Modern neuroscience has also suggested that there is a strong association between Broca’s area and motor control (Jang, 2009), which is perhaps unsurprising given its close proximity to the primary motor regions of the brain. This may suggest that Broca’s aphasia may be at least partially a motor deficit rather than a strict language deficit. Although this seems to contradict the classical model, it was proposed by Broca’s contemporary, John Hughlings Jackson, as long ago as 1868 (Lorch, 2008). A motor association with Broca’s area may indicate that verbal language ability evolved as a result of motor expressions, such as hand gestures, that preceded it.

The limitations of comparing classical and contemporary models

The concept of language as defined by Broca, Wernicke and their contemporaries was arguably rather crude by the standards of modern neurolinguistics, as it consisted almost solely of expression and reception. The current interpretation of language is somewhat more nuanced, and encompasses concepts such as the difference between spoken and written language, semantic meaning, visual imagery, phonetics, working memory and non-verbal cues. For example, Fedorenko, Gibson, and Rohde (2006) examined the role of working memory in sentence comprehension, and Just (2008) observed that when we hear spoken sentences that prime mental imagery, activation occurs in the intraparietal sulcus. This level of scrutiny highlights the failure of the historical model to appropriately consider the complicated subcomponents of language. Therefore one could argue that historical and contemporary thinkers are not necessarily describing the same phenomena when they refer to language. In addition, the region referred to as Broca’s area varies considerably between studies and over time (Dronkers, et al., 2007), meaning many studies of language may not even be describing the same neural region as Broca discovered.
As a note of caution, both the techniques employed by classical and contemporary neuroscientists are to some extent methodologically flawed. One must use caution when using a lesioned brain to make inferences about normal functioning as we cannot guarantee that the unlesioned areas are functioning as normal (Rorden & Karnath, 2004), and we now know that many neural regions can adapt their function to compensate for damage elsewhere (Robertson & Murre, 1999), such as the right hemisphere adopting some of the lost language functioning resulting from lesions to the left hemisphere (Knopman, Rubens, Selnes, Klassen, & Meyer, 1984). Similarly, the interpretation of modern imaging techniques can be scientifically dubious. For example, the association between activation and cognitive processes can be ambiguous, it is unclear whether observed neural activity is related to excitation or inhibition of a particular function, and the arguments raised in the modularity debate may well confound any activity observed as most imaging studies assume a brain modular in function (Poldrack, 2006). For these reasons many imaging studies of language may well be methodologically unsound.

Conclusion

Although Broca and Wernicke introduced some of the key neural regions associated with language, these represent only a fraction of the brain regions that now seem to be involved in language, and the historical model was unable to speculate on the complex circuitry by which the many areas involved in production and comprehension interact. Neither Broca nor Wernicke was wrong per se, but the discoveries of each continue to be refined and re-evaluated in the light of technological and methodological advances. This is not to diminish their discoveries; the cumulative way in which science progresses means that the pioneering research conducted by the likes of Broca and Wernicke, and their unabashed willingness to disregard the received wisdom of the age, was a vital bedrock for the rapid acceleration in what we know today about language in the brain.

And relax...

2010-02-11T21:48:00.002Z

I just submitted 2 major pieces of coursework I have been working on for some time, what a relief.

Over the last week I have become somewhat obsessed. On Monday, I took part in a neuroimaging experiment which involved going in an MRI machine. The lady who conducted the study was nice enough to let me keep the data file produced by my scan.

Which means I can now do all sorts of fancy things on my laptop, not just make images like this:

But also make fun videos like this:

And, I just discovered, I can convert the scan in 3D, which looks a bit like this:

Look out for the upcoming guided tour to my brain.

What, you think I'm joking?

2010-02-01T18:14:00.004Z

On Sunday I got my first glimpse of some serious neuroimaging machinery.

My supervisor invited me along to watch him testing a participant in an experiment that is very similar to the one he and I will be conducting in a few months time.

The participant was required to under go an MEG, or magnetoencephalogram.

Just like this one...

Although MEG is not strictly an imaging tool, it does allow us to view brain waves in different parts of the cerebral cortex. It works by recording the electrical activity at over 270 points in the brain. Once this is done you can examine the data to see what activity correlated with the task the participant was doing. Clever stuff.

The participant was sat in the machine and played a series of tones, at 2 different pitches, some of which were doubled in length. He had to press a button every time he heard a longer tone.

Halfway through the test one of the tones became associated with an electric shock to the forearm.

Christian didn't explain to me the exact nature of this study, but it is very similar in nature to the one we proposed (a few entries back in this very blog, if you want to read about it).

Oh, and I've volunteered to take part myself next week, and in addition I might be taking part in an fMRI experiment too, which I will tell you all about if it comes to pass.

Exciting times!

As we move into term 2...

2010-01-18T19:22:00.003Z

As hard as it may be to believe, I am now in the second of the 'taught' terms of my MSc. This means I have lectures until the end of March, and after that I will concentrate solely on my research project.

But before the second term could start there was the small issue of the exam for Marty Sereno's module, 'structure and measurement of the human brain'. This was the module I had been struggling with a little bit, as had many of my cohorts, as it straddled cellular biology, the molecular physics of magnetic resonance imaging, and topics such as chemistry and embryonic development. This was a bit tough for poor old me, who had not done any science or maths since my GCSEs, and had always been stronger in the humanities.

If you are interested, you can see the practice exam paper here.

Anyway, it wasnt half as bad as many of us had feared, and frankly as long as I pass (of which I am pretty confident) then I'm happy. Plus there is the added bonus of knowing that this will probably be the last exam I ever take.

Now the exam is out of the way the pressure if off for a little while, but I do have a couple of essays to be getting on with, as well as getting on top of my research project. This quiet moment won't last long, so I intend to try and get a head start on the assignments for this term as soon as possible.

I did, however, award myself the weekend off.

Research proposal for dummies

2009-12-20T13:02:00.001Z

Here you go, as promised a rewritten project proposal written for beginners to neuroscience. Not quite a plain English rewording, but simplified and with key terms defined. This is what I will be doing up until September...

The way in which the brain that processes our main senses, such as sight and hearing (and by the way, don’t go thinking you only have the 5 senses we all know about, there are far more!) is fascinating. They are what we call ‘topographically organised’. Which basically means that the surface of the brain, the cortex, acts as a little map of what we perceive. For example, if you could look down on the main visual area of your brain, called V1, and see what each brain cell is processing, it would look more or less the same as the picture you see out of your eye (although this is a hugely simplified explanation, but you get the general idea).

The hearing process is slightly different. In another simplified explanation, sound is processed in terms of what we perceive as the ‘pitch of a sound’, or how ‘high or low’ it sounds; its frequency. Each frequency (or note, if that makes it simpler) is processed by a separate part of the primary auditory cortex, or A1. These areas of the A1 are also organised by frequency, a bit like the keys of a piano going from low up to high pitch notes. So if you were to scan the brain and run your hand down a piano, you would see a ripple of activation move along A1. The range of frequencies that each auditory brain cell responds to is called it’s ‘receptive field’.

If you read to the entry I wrote recently about neuroplasticity you will know that the organisation of the brain, or its ‘wiring’ can be changed. When this occurs to our sensory areas we can think of this as ‘remapping’. Research in animals has shown that the receptive fields of neurons in AI can undergo these ‘plastic’ changes very rapidly, as a result of what the animals learns to associate particular sounds with. Amazingly, these changes occur within minutes.

If something happens to make the animal associate a particular frequency with something external, the tone acquires behavioral relevance and a large number of these AI cells shift their preferred frequency and begin to respond more to the new frequency. This effect has been shown to depend on the animal paying direct attention to the stimulus. In one experiment, two groups of rats were trained to respond to musical tones. One group responded to the frequency and the second group responded to the volume of the tone. So, each were played a series of tones at either different frequencies or different volumes, and had to respond only to the frequency or volume to which they were trained to respond. The frequency rats demonstrated changes to the frequency map in the A1, with more cells firing in response to the trained tone. This didn’t happen in the rats who were trained to respond to loudness, but they did have an increase in the type of cells that respond to volume rather than frequency. This would support the idea that brain cells can be changed depending on what an animal needs them for, and what sounds hold a particular relevance for the animal. Other studies have achieved the same result without training the animal, instead electrically stimulating parts of the brain, such as the nucleus basalis, when the animal heard a particular frequency.

However, very little work has been done in humans on this subject. So our study aims to determine whether conditioning of a particular frequency can lead to improved performance in detection and/ or discrimination of that frequency amid others, as would be predicted if human receptive fields show similar plasticity to that documented in animals.

What we are planning to do is to compare the ability of people to detect a particular frequency as well as to discriminate between the frequency and others close by. In the detection task subjects will have to decide which of two successive bursts of white noise contained a ‘hidden’ embedded auditory tone. In the discrimination experiment participants will be required to decide whether the second of two successively presented pure tones was higher or lower than the first.
After this initial detection / discrimination task, subjects will undergo a training method known as ‘classical conditioning’, repeatedly pairing one distinct target frequency tone with an electric shock to the forearm so the participant comes to associate that frequency with receiving a physical shock. After this association is established, the detection / discrimination tasks are repeated, with an occasional “topping up” of the shock conditioning. After 40 minutes, the detection / discrimination task will continue without further conditioning. The absence of reinforcement of the target frequency will then lead to what is called “extinction” of the association between frequency and shock. We will then compare the ability of participants to spot the tone to which they were conditioned before and after the task.

If the animal studies are applicable to humans there is likely to be a greater number of brain cells in A1 detecting the target frequency, because it has become associated with the electric shock. More cells responding to that frequency should make people better at spotting it. If we find a significant effect we may then go on to repeat the experiment while monitoring brain activity using a method known as MEG, to see what is going on in the brain during the experiment.

2009-12-19T01:50:00.001Z

Oh, and I'll post a simplified explanation of that last post soon!

Research Proposal

2009-12-18T20:12:00.004Z

Today I had to submit my research proposal for my thesis project. Here it is, written by myself and Dr Christian Kluge:

Rapid plastic changes in Auditory Cortex: a classical conditioning paradigm

Chris Fassnidge, Dr Christian Kluge and Professor Jon Driver

Aim

This study seeks to determine whether detection and/or discrimination of a pure auditory tone can be improved by classical conditioning, pairing a target frequency with an electric shock

Literature Review

Work by Merzenich, Weinberger, Irvine and others has shown that receptive field properties of neurons in primary auditory cortex (AI) can undergo rapid plastic changes in response to behavioral learning in animals (reviewed in Weinberger 2004, Weinberger 2007, Irvine 2007). Remarkably, these changes occur within minutes. During learning, when a target frequency acquires behavioral relevance a large number of AI pyramidal cells shift their best frequency towards this distinct frequency. This effect has been shown to depend on attention , i.e. behavioural relevance (Polley et al., 2006). Two groups of rats underwent operant conditioning with identical stimulus sets. One group responded to a target frequency and demonstrated tonotopic changes resulting in an increased representation of the target frequency, while the second group performed the task (with exactly the same stimuli) in response to a target loudness which led to changes in the topographic organisation of neurons’ preferred loudness. In non-human primates, Blake et al. (2006) demonstrated a crucial role for active cognitive control and involvement needed for tonotopic re-mapping to occur.

Later mechanistic assessment has revealed that the neurotransmitter acetylcholine (ACh) is crucially involved in these plastic processes. Pairing brief ACh infusions with the purely passive presentation of tones induced changes in the AI tonotopic maps similar to the ones observed in the experiments described above. In addition, stimulation of the nucleus basalis, the main source of corticopetal cholinergic projections, led to identical remapping. These findings are intriguing because they strongly argue against the long-held view that primary sensory cortices are merely passive input structures in which plastic changes of receptive fields occur only during early ontogeny. Instead, the studies summarised indicate that the sensitivity and perhaps even local network resonance patterns can be dynamically adapted to current behavioural requirements.

Very little work has been done in humans on this subject. Thus, we aim to behaviourally determine whether conditioning of one or another frequency can lead to improved performance in detection and/ or discrimination of pure tones, as would be predicted if human receptive fields show similar plasticity to that documented in animals.

Materials and Method

In a within-subject design (with conditioned frequencies counterbalanced over subjects), we will compare the detection (experiment A) as well as the discrimination (experiment B) of pure tones. The detection task will employ a two alternative forced choice (2AFC) scheme in which subjects have to decide which of two successively presented white noise stimuli actually contained a pure tone. In the discrimination experiment, participants will be required to decide whether the second of two successively presented pure tones was higher or lower than the first one. In both experiments tones of a range of frequencies will be used and this part of the experiment will last about 15 minutes.

After this initial detection / discrimination block, subjects will undergo classical conditioning, pairing one distinct target frequency tone with an electric shock to the forearm. After this association is established, the detection / discrimination 2AFC routines are repeated, interleaved with further conditioning blocks (“topping up”). After 40 minutes, the detection / discrimination task will cease to be interupted by further conditioning. The absence of reinforcement of the target frequency will then lead to extinction of the association between frequency and shock (extinction).

A number of potential follow-up studies are conceivable. First, the work by Blake and colleagues (2006) suggests that operant conditioning might be more effective in inducing tonotopic changes. Thus, modifications of the paradigm employing reward or punishment depending on performance are possible. Also, there are potential MEG versions of all experiments described which would, through analysis of early latency auditory components of the evoked magnetic fields, allow for a direct assessment of the underlying neurophysiological principles.

Predicted Outcomes

This series of experiments allows for three possible outcomes:
1. Conditioning may improve tone detection performance but not tone discrimination. This situation would allow for the conclusion that a greater number of neurons areresponding to the target frequency after conditioning but that this improvement does not involve a sharpening of best frequency tuning curves.
2. Conditioning may improve tone discrimination performance but not tone detection. This outcome could be interpreted as a potential increased local signal-noise ratio. This situation seems somewhat unlikely, however, since previous studies reported best frequency shifts in large numbers of cells rather than sharpening of existing tuning curves.
3. Finally, if conditioning leads to performance improvements in both detection and discrimination our interpretation would be that although there was an increase in the number of neurons responding to the target frequency, this change does not come at the expense of frequencies around it. In this situation it would be interesting to study the underlying compensatory mechanisms in a later MEG experiment.

Analysis

The data will be analyzed with ANOVA (random effects) using the SPSS statistics software package. Further analysis may be required depending on results.

Timetable

Preparatory work: January - March 2010
(generation of stimuli, programming of the actual experiment, pilot measurements)
Data collection: March - June 2010
(16 to 20 subjects each group)
Analysis and write up: June - July 2010

Budget

Participants will be reimbursed for their time and effort using existing research grants of the ICN attention group. No investment in equipment or software will be neccessary.

Ethics

Full ethical approval will be sought from the Graduate School Research Ethics Committee prior to pilot data collection. The ethics application will be submitted in early January 2010.

References

Blake, D. T., Heiser, M. A., Caywood, M., & Merzenich, M. M. (2006). Experience-dependent adult cortical plasticity requires cognitive association between sensation and reward. Neuron, 52(2), 371-381.

Irvine, D. R. F. (2007). Auditory cortical plasticity: Does it provide evidence for
cognitive processing in the auditory cortex? Hearing Research, 229(1-2), 158-170.

Polley, D. B., Steinberg, E. E., & Merzenich, M. M. (2006). Perceptual Learning Directs Auditory Cortical Map Reorganization through Top-Down Influences. The Journal of Neuroscience, 26(18), 4970–4982.

Weinberger N. M. (2004) Specific long-term memory traces in primary auditory cortex. Nature Reviews Neuroscience, 5(4), 279-290.

Weinberger N. M. (2007). Associative representational plasticity in the auditory cortex: a synthesis of two disciplines. Learning & Memory, 14(1-2) 1-16.

2009-12-10T23:30:00.002Z

My apologies, but this may be a rather lengthy, self-indulgent entry.

There are times on this course when I really need to take a deep breath and swallow down the surge of inadequacy that I feel building up inside me. It is something akin to those moments in life when one almost throws up but somehow at the last second manages to swallow down the noxious brew. Both avoid leaving oneself in an unpleasant position, but equally leave you with a revolting taste in your mouth.

A tad overdramatic? Perhaps.

It is fair to say, however, that I often feel out of my depth on this course. Those of you who have read my past entries in this blog will know that my school record was far from exemplary. You will also know that I have felt more than a slither of trepidation at being accepted to study at such a prestigious institution, a world leader no less.

It has not been the finest of weeks. Monday started off optimistically enough, with a meeting at the Institute of Cognitive Neuroscience (ICN) to discuss my upcoming research project with my soon-to-be collaborator, Dr Christian Kluge. I left the ICN buzzing at having drawn up an exciting and original piece of research with Dr Kluge, and feeling a lot more confident about what would in the new year become the embryonic stage of my thesis.

How crushed I was then, on returning home to see in my inbox the following words from Dr Kluge:

“There is an ongoing project with quite similar designs that i did not know of. Therefore, we will probably have to re-think what we want to do”.

A lesson in expectations management, perhaps. That’ll teach me to curb my enthusiasm!

Anyway, there was little time to waste, as in seven days I time I would be required to make a brief presentation to my peers and the course administrators outlining my research project. What Dr Kluge proposed was we meet with Professor Jon Driver, one of the directors of the ICN and the man who would be supervising the project that myself and Dr Kluge will spend the next nine months on.

It didn’t go well.

I came across as a bumbling, poorly read amateur. Prof Driver was clearly unimpressed, and Dr Kluge was visibly embarrassed at having brought me into his office. Nevertheless, between us we managed to thrash out a viable research project which certainly has potential to be an exciting piece of work.

The one advantage of making such a poor first impression on such an important figure within the ICN is that there is now only one direction in which his opinion of me can go. The last thing professor Driver asked of me, as he was on his way into a two hour meeting, was to draw up the slides for my presentation on Monday, and to do it before Friday so he could take a look at it.

It was in his inbox by the time he left the meeting.

The best thing about fighting down those feelings of inadequacy is that it resets ones perspective in order that we may replace them with feelings of pride and self-congratulation; quite rare for me to feel and even rarer to voice. But if I am honest I have done bloody well to get here. It can be off-putting at times to hear some of my fellow students list their accomplishments, to reel off terminology that leaves me perplexed, and to have to take the time to explain things to me in simple terms.

I should not lose sight of the fact that I came into this course without a single science A-level, and ten years after a decidedly average performance at GCSE science. In addition, contrary to what some may think, a psychology degree is far from the ideal prerequisite for a cognitive neuroscience MSc, let alone one with as little scientific content as my bachelors degree had. But then again, I had no experience of psychology before undertaking my degree, and emerged with first class honours.

This may all be new to me now, and I may have to endure some snobbery, condescending comments and pangs of self-doubt, but I will learn fast, improve exponentially and come out the other side with one heck of a valuable qualification.

And then, just maybe, repeat the whole cycle again with a PhD.

2009-12-03T23:13:00.000Z

Some people are just ahead of their time.

"Men ought to know that from nothing else but the brain come joys, delights, laughter and sports, and sorrows, griefs, despondency, and lamentations. And by this, in an especial manner, we acquire wisdom and knowledge, and see and hear, and know what are foul and what are fair, what are bad and what are good, what are sweet, and what unsavoury... And by the same organ we become mad and delirious, and fears and terrors assail us... All these things we endure from the brain"

Hippocrates, 400 B.C

Neuroplasticity.

2009-11-25T00:37:00.003Z

Not much to report over the last couple of weeks, I had a reading week recently and actually managed to get rather a lot done, having spent several hours in the library making notes on this and that. It was a much needed 'break' of sorts, if only from the time-tabled activities.

I am currently trying to think of a research project which will form my thesis. I have a pretty good idea who will be supervising me, a guy over at the institute of cognitive neuroscience who is researching plasticity in the auditory cortex.

Plasticity is something that fascinates me greatly, and one book in particular, 'the brain that changes itself' by Norman Doidge, was more or less the main reason why I applied for this particular course.

Essentially, plasticity (or neuroplasticity) is the ability of the brain to 'rewire' itself, to make new connections. For the century or so since the 'neuron doctrine' came to the forefront of thinking about the brain, it was believed that the structure of the brain was more or less fixed from adolescence onward. Scientists thought that no new brain cells could be formed, and it a part of the brain was damaged then it was lost for life.

Of course, there has to be some degree of plasticity in the brain, otherwise we couldn't form new memories, but we now know that the brain is far, far more plastic than previously thought.

The most exciting research being done in this field that I am aware of is in the area of sensory substitution, most notably the work carried out by a guy by the name of Paul Bach-y-rita.

Bach-y-rita developed a device which could allow the brain to recover one lost sense from another. If I wanted to sensationalise this, I would say he made blind people see again. But that wouldn't quite do him justice - he made them see out of their tongue.

Sounds insane, but it is actually possible. The key concept here is that we don't see with out eyes, just as we don't hear with our ears. All of our senses are essentially electrical information carried to and processed in the brain. For example, the actual physical image of what you see doesn't get any further than the back of the retina, before it becomes a complex series of electrical pulses that are then carried to the visual areas at the back of the brain.

When somebody is blind, it is generally because of a problem with their eyes, rather than the visual areas of the brain. Therefore if an alternative pathway could be found to get these electrical pulses to the visual cortex, you have vision.

What Bach-y-rita invented was a small device that sits on your tongue and converts a picture from a video camera into electrical information. Imagine a strip of plastic with hundreds of tiny electrical points covering it's surface. Each one of these points is like the pixels that make up a digital image, the brighter the pixel the stronger the electrical pulse. Multiply this over the entire surface of the tongue and you can make up a crude image of your visual field. Apparently, when this device is activated it feels like those old 'popping candy' sweets you can get that fizz in your mouth.

The amazing thing is, over time your brain learns how to process the signals as images, and slowly the signal becomes a valid, if slightly basic, black and white image. Brain scans using MRI machines have even confirmed that this information is being processed in the visual parts of the brain.

So this now becomes a philosophical question - if visual information is being processed in the visual cortex, but it just so happens it is relayed via the tongue by a video camera - is this still eyesight?

Take a look at these two videos and decide for yourself.

A little fact.

2009-11-09T12:00:00.002Z

Hello everyone,

I realise that my last entry was pretty dull, so I found out an interesting little fact to keep your interest.

There are 100-150 billion neurons in the human brain.
Each neuron may connect with around 10,000 other neurons.
If each neuron connected with every other single neuron, our brain would be 12.5 miles in diameter (Nelson & Bower, 1990). This is the size of greater London.

Taken from Jamie Ward's book 'The students guide to cognitive neuroscience', chapter 2.

Weeks 4 & 5

2009-11-08T15:31:00.002Z

Over a month into the course now, and my predominant feeling is exhaustion. I can't particularly explain why, but I am bloody tired. How handy it is then, that next week is a reading week, and it couldn't have been timed better.

There isn't a great deal to report about the last fortnight. We had some interesting lectures and some achingly dull ones. We learnt a little about how computational modelling can help us to understand the brain, had another case study at the hospital, and a whole load more stats.

I got my marks back for the first statistics test as I was handing in the second assignment. I did reasonably well, considering the conditions under which I wrote the last one (see my previous entry on my late-night rewrite). The marks I dropped were, I think, due mostly to the length of time it has been since I had to do any statistical analysis, and a couple of silly mistakes. I feel a lot more confident about the second test, and it would seem that I am back into the swing of things.

My main worry now is the exam in January (the only exam on this course), which is on the neurophysiological side of the course. Of course, this stuff is bloody hard, and Marty has just put a few example questions on his website, which really put the fear into me. As I was rereading my notes on how brain cells communicate with one another, I was struck by just how easy this would be it the brain were intrinsically self-aware. My neurons are firing right now, in many different parts of my brain, as are yours, as are all of ours, all the time, many many times over. We should be experts in this. Given the frequency with which our neurons fire you could argue that it is the single most practised act any human has ever performed.

So why then is this exam shaping up to be such a struggle?

Week 3

2009-10-23T17:42:00.001+01:00

The third week in, and things are getting tougher. On the plus side, though, certain things are getting more interesting.

For example, we had a lecture explaining how an MRI (magnetic resonance imaging) scanner is able to capture such detailed images of the brain. Would you like to know how it works?

Essentially, an MRI scanner is a tube containing a very strong magnetic field, thousands of times stronger than the Earth’s gravitational pull. This field is kept constant, so is absolutely uniform at every point within the scanner.

The protons inside the head are all busy jiggling around all over the place, randomly veering around at different angles, but once inside the scanner they all begin to align, with every proton facing the exact same direction, due to the power of the huge magnetic force generated by the machine.

The operator can then send a strong sudden magnetic pulse through the scanner, which flips every single proton in the scanner chamber to one side. To help you imagine this, picture all the protons facing north, and then suddenly being knocked to face east (of course this is not how it happens, but it can be easily visualised).

Now, this is the clever bit. The protons will then flip back to align with ‘north’, only in every different type of tissue this process will take slightly different amounts of time. So, bone, grey matter, white matter, even oxygenated and lesser oxygenated blood, each will take a slightly different time for their protons to recover from the knock in order to face ‘north’.

This different timing for each type of tissue is crucial, as the scanner can keep a record of how long each proton took to recover, and this will effect whether a light or dark patch appears on the screen, giving us a perfect image of the skull, brain and surrounding tissue.

Amazingly, the machine can do this in 3d, so you can then work through sections of the brain as if you were travelling through the body.

It is quite an amazing procedure, and if you are interested you can see more here
.

On an unrelated note, I had my first bit of coursework due in yesterday, a particularly nasty statistics worksheet. The night before it was to be handed in I had got it all finished, printed off, done and dusted. My first early night in ages, I was actually in bed by 11 which is unheard of.

12:30 a.m, I get a phonecall. It is Melissa, a girl on my course, who I collaborated with on the work. She tells me there was an error in our data, meaning all our calculations were wrong. So, at one in the morning I had no choice but to rewrite the bloody thing from scratch, redoing all my calculations, graphs and tables. I got to bed some time after 4 a.m, a bit of sleep, and handed it in an ten the next morning.

Ouch.

The course enters the real world.

2009-10-18T15:56:00.005+01:00

To my left-hand side sits a sheet of paper entitled 'Advanced Quantitative Methods - Assessed Coursework: Worksheet 1'.

To my right-hand side sits a pile of my old undergraduate study aids, module guides, notes and help sheets.

Directly in front of me sits my laptop and, next to that, three textbooks, one intimidatingly large yet deceptively simple, the other two smaller and more advanced.

What do these myriad documents have in common? If I were to hazard a guess I should suggest that they were faxed to me direct from Hades by Satan himself, written in his own blood and printed on the compacted bones of history's greatest tyrants. But in reality the truth is far more sinister. For what links these formidable documents is a word, one single word, that strikes fear into the hearts of countless generations of poor psychology students.

Statistics.

Or maybe it's just me. See, I have always struggled with numbers. Words, on the other hand, have always come naturally to me, flowing from my lips (or as is increasingly the case, fingertips) without any kind of difficulty, but numbers, with their logical structure and stubborn insistence on being 'right or wrong' make me want to curl up into a little ball and cease to function.

Anyway, this was not supposed to be a moaning entry about the stats coursework I am currently writing. All you really need to know is that I looked at the questions, started to panic, stopped panicking and all of a sudden it all started to come back to me, albeit in a trickle rather than a flood.

No, my real intention for this entry was not to moan about statistics, but to rejoice in how wonderful Thursday was. Every other Thursday, as part of our 'lesion approaches' module, we are invited over to the National Hospital for Neurology and Neurosurgery for a real life case presentation.

What this entailed (although obviously I can't be specific, in the interest of the confidentiality of the patient) was a short talk from some of the senior doctors about a specific patient, how their brain has been injured and how the injury has affected the patient. The patient was then brought in and took part in a short mock examination whereby the doctor tested various aspects of cognitive function with a series of standardised tests. We were then given the opportunity to ask the patient questions about their injury and subsequent experiences. The patient then left and we had a discussion about the case and the opportunity to ask the doctor any questions about the case.

It was absolutely fascinating, and really brought this MSc course crashing into the real world. I was overwhelmed by the generosity of the patient at coming in to discuss such a personal and traumatic experience, and I feel that these case presentations will be an incredibly valuable part of the course.

Oh well, that is quite enough enthusiasm for one entry. I must get back to the utter joy of these statistical calculations.

Wish me luck!

Start of week 2.

2009-10-13T21:43:00.000+01:00

Week two began once again with Structure and Measurement of the Brain, delivered by Marty Sereno, who I hadn’t quite appreciated until now is one of the world leading researchers in his field. Anyone interested can see him at work below.

The topic this week focused on the development of the brain in the womb, with a detailed explanation of how a small cluster of cells begin to slowly divide and form the beginnings of the spine, the eyes and gradually folds over on itself to take shape as the infant brain. This was fascinating, and I was really impressed by Marty’s knowledge, with frequent deviations to discuss the brains of other mammals and assorted creatures of all different sizes.

He then went on to discuss the visual system, and how surprisingly complex it is. We have no idea quite how much our brain needs to do in order to make sense of the world around us. For example, what we perceive as a single field of vision is actually processed in several different parts of the brain, such as an area for the periphery, an area for our immediate focus etc. These different maps are then seamlessly patched together in order that they be perceived as one single image. This on top of flipping the image (due to the convex shape of the retina), and creating a 3D image of the world via depth perception, all happening simultaneously without us knowing it. He also discussed the limitations of our knowledge of just how this is done, with particular reference to objects moving across our field of vision.

We had an extended lecture with Marty, 3 hours rather than the usual 2. He actually managed to maintain my full and undivided attention for almost the full 3 hours, until that is he started talking about areas of the visual cortex known as (I kid you not) ‘blobs’. This was about the point when both my interest and understanding trailed off, the final straw being the point that the areas between the ‘blobs’ are known as ‘interblobs’. Frankly if scientists can’t be bothered to name these things properly, I can’t be bothered to understand.

The reading Marty set us this week is much more accessible too. One bit I found particularly interesting is how the brain of a tennis player will come to perceive his or her racquet as an extension of their arm, increasing it’s mental map of their immediate surroundings to compensate for this increased ‘body shape’.

This follows research by Iriki et al (1996) on monkey using sticks as primitive tools, and the science is explained thusly:

“The visual receptive fields expand when the monkey uses the rake as an extension of its hand, while the somatosensory receptive fields are unchanged. This is interpreted as a change in the body image: The enlargement of the visual receptive field reflects the neural correlate of a hand representation that now incorporates the tool. The visual receptive fields return to their original size within a few minutes after tool use is discontinued. They do not expand at all if the monkey simply holds the rake without intending to use it. These rapid changes in visual receptive field size indicate that the neural connections that allow for the expansion must be in place all along.”

(Colby, C.L. and M.E. Goldberg (1999) Space and attention in parietal cortex. Annual Review of Neurosciences 22:319-349).

Anyway, as challenging as this module is I feel it may end up being a very rewarding one, and perhaps even a personal favourite, as long as I can keep up with the reading material, and maintain the pretence of understanding it.

The afternoon talk was delivered by a guest lecturer who gave a talk on Autism and Williams syndrome, both examples of what can happen when certain parts of the brain don’t function as they should. Frustratingly, all she did was read out her lecture slides without any elaboration, meaning she may as well have just emailed us all and we could have read the bloody things in 20 minutes. It didn’t help that she pitched the thing at GCSE to A-level standard, not far above the quality of science you would expect on ‘loose women’. And yes, I am fully aware that last week I was complaining about things being too hard, only to complain this week that it is too easy.

But then I’m a fussy little so-and-so.

Week one in review.

2009-10-09T22:39:00.001+01:00

As the first week of fifty passes, it seems appropriate to stop and reflect on the last five days. Granted, it wasn't technically the first week (we had a week of introductory talks, induction sessions and general 'getting to know people' type events last week) but it was the first week of teaching, and my first class on Monday morning left me with a heavy heart.

Now, much had been made by the lecture staff about the wide variety of backgrounds and experiences we, the students, had prior to the course. For some this is their second or third masters, but for the majority it is their first postgraduate qualification. Many, like me, graduated with a BSc or BA in Psychology, but there is also a wealth of other talent on board, from computer science students to those who studied linguistics. Some studied neuroscience, and others had a more biomedical background.

Therefore one would hope that the lecture staff would really start with the basics, and build up to more complex and specialist information. Sadly not. My main complaint about Tuesday morning is that Marty Sereno, who teaches 'Structure and Measurement of the Brain' (which encompasses Neuroanatomy, Neurophysiology, and Neuroimaging Physics)seemed to assume we were all already familiar with pretty advanced maths, physics and chemistry concepts, and wasted no time in explaining much of the terminology he employed. For poor old me, who hasn't done any maths or real science in the last decade (not since the last century, in fact) this was a bit of a problem.

This was exacerbated by the fact that, rather than starting at the beginning, Marty seemed to deliver the points of his lecture in a bizarre mixed up order of concepts, often explaining how a process works far before explaining what the process actually is and does. Passionate he certainly is, and his knowledge seemed superb. But when I asked a question (basically 'what on earth are you talking about') he merely stated he would come back to my question, and then promptly forgot.

Luckily when I went home and began to plough through the reading things started to make sense. I now have a basic understanding of the signalling processes employed by neurons (or brain cells), which is far too dull to even bother explaining here, but in very simple terms it has to do with flipping the balance of positive and negatively charged ions inside and outside the cell wall to create a sudden electrical charge which then fires along to the next brain cell to convey the signal. Simple, and it only took a few hours of reading.

The rest of Tuesday was pretty much administrative stuff, learning about the departmental intranet and IT services and a little information about our major project for the course. We also discussed applying for PhD funding, which needs to be done very soon indeed. This presents me with a bit of a problem, as a large part of my reason for doing this course is that I don't yet know what field I want to go into for my PhD, and so was hoping that the masters would give me extra knowledge of all aspects of neuroscience. So it came as a bit of a shock to learn that I would need to apply for funding within the first month of the course. Arse.

By the time my second day of lectures came around, I was still worrying about my experience of Mondays class. Surely it couldn't all be this hard? If week one was going to be that complex then what the hell was week ten, twenty or fifty going to be like?

Luckily, I was presently surprised by Thursday, as much of it was very basic revision of the statistical concepts I had learnt at undergraduate level. I would say I was already familiar with about 90% of what was discussed in out first 'Advanced Quantitative Methods' class, and looking over the timetable for the coming months most of this module does seem to build on concepts with which I am already familiar. I had been dreading statistics, but I left the class feeling very, very relieved.

Which brings me on to my final class of the week, 'Lesion approaches'. This class covers what we can learn about the brain by examining what effect is observed when a specific area of the brain is damaged, and the impairments it causes. I have a feeling this may become a personal favourite of mine, and although week one was very basic and introductory in tone, it did not disappoint.

So there you have it, week one. Sorry there wasn't much to report, but due to the nature of these things this first week was mostly spend getting to know the staff, finding out where we needed to be for each class and discussing what we will be learning over the next 12 months.

I would imagine that as of Monday, the exciting stuff starts! But don't worry, I will be here to keep you posted!

The joys of reading

2009-10-08T02:43:00.000+01:00

Good lord, it appears I am going to spend 23 hours a day for the next 12 months solidly reading.

I may have hit a snag in my plan, which at first seemed simple. I would take what I have learnt on the course and post it in an informative, witty and simple format whereby anybody could understand and appreciate the wonders of the brain.

As I said, that was the plan. Cast your eyes over this little lot:

Now, I appreciate that those are all real words, and many of them may even appear in the English language. Just, not all at once and certainly not in that order.

That is one page out of sixty that make up this article.

For this particular module, we have been given three articles to read this week. Three core articles, and then a series of other 'suggested readings'.

I have four modules running simultaneously at any one time, each with their own prescribed reading list.

(Neuro)genesis

2009-10-07T20:34:00.000+01:00

After what has felt at times like the longest of all summers, October has arrived, and with it my opportunity to embark upon a Master of Science degree.

This has been more than a little daunting, and I must admit that to many it is probably also pretty surprising (with good reason).

Here is, then, a little background information about me, and I promise that after this entry I will stick to detailing my experiences of the course, the field of cognitive neuroscience, and try and express what I am learning in easily digestible chunks. But for now, the autobiography commences:

When I was at school I was always what could be considered an 'under-performer'. Although many teachers over the years noted that I was pretty bright, this observation was almost universally followed up with an immediate 'but'. Typically my school reports would highlight the fact that if a subject did not capture my imagination I just wouldn't bother. Conversely, if it did capture my over-active imagination then I would invariably achieve very highly. In an ideal world this should not present a problem, but god knows a good teacher is hard to find, let alone one who will infuse each and every lesson with a spark of excitement and passion, meaning that more often than not my work failed to live up to my potential.

Not that I should attempt to absolve myself of blame absolutely, more often than not I was more than happy to let myself coast, often only expelling the bare minimum effort needed to scrape by with a moderately acceptable grade. Consequently I did just fine. Nothing great, but enough to ensure that the only way in which my memory would live on in my old school will be in the tales passed down the years about my childish and troublesome, albeit somewhat amusing behaviour (details about which are probably best left for another forum).

Anyway, I left school as the nineties turned into the naughties, and after a very uneventful gap year I enrolled, hated, and subsequently dropped out of a drama degree, all within the space of a term. While away I had become quite depressed which put me off academia for quite some time. This left a substantial gulf in my life, which I filled with a job working in a bar, and I was soon climbing up the rungs of a career ladder I had no real desire to be climbing, with promotion to bar supervisor and the offer of a place on a management training scheme. Four years passed, stuck serving the same old drinks behind the same old bar to the same old idiots, and it was becoming depressingly clear that I had no idea what to do next.

The trouble with bar work is it does not afford you much time to research career prospects - particularly when you have none. The combination of long hours (15 hour shifts, anyone?) late finishes and working all weekend meant I had little time to consider my options, let alone draw up a strategy for how to act on them. So I took some time out. I saved up as much money as I could muster and jetted off to New York City. For 3 months.

Finally, a chance to clear my mind of distractions, and to give some real thought as to what I would enjoy doing, and to what I would be particularly skilled at doing (oh, and to have some much needed fun in one of the best cities in the world!).

The result (drum roll please.....) I decided I wanted to become a hypnotherapist. Only I didn't, I just didn't yet know that I did not want it.

Anyway, to cut what was supposed to have been a short story at least relatively short, logic dictated that a psychology degree would be a good springboard for such an aspiration, and so I picked a London university at random, ending up at St Mary's University College in Twickenham.

To be fair to St Mary's, it was a very small campus, and therefore had very limited facilities. The psychology department was great, with some wonderful academic staff, but looking back the university itself wasn't great, and I didn't really fit in to university life on a campus that was primarily sports based. But, as you know by now, I didn't have the best set of A-levels, so I just had to work bloody hard to make up for all those years of slacking, and emerged in the summer of 2008 with a first class honours degree.

As you will know, the summer of 2008 also coincided with the start of a global recession, which rather buggered my employment prospects, but after six months on unemployment benefit I took a job in a medium-secure psychiatric hospital, giving me some great entry level clinical experience. Some good news, finally! Good news which was followed by some further good news, Goldsmiths College wanted me for their Cognitive and Clinical Neuroscience MSc! As great as this sounded, I had my sights set on UCL, and the amazing course they had to offer.

The months rolled by and UCL remained silent, while I remained at the psychiatric hospital (still as staff, I might add) until, eventually, I was accepted onto my dream course.

And we arrive back at the never-ending summer, which has now ended. I am here. Studying at one of the top 5 universities in the country, and one of the top 10 in the world. On one of the top 3 neuroscience courses on the planet. Perhaps now you can see why I started off by saying I was a little daunted by the whole experience.

Now the history is out of the way, I can begin the exciting stuff, the reason I am here in the first place. Cognitive Neuroscience. The biological underpinnings of mental activity. Or something like that, at any rate. I will endeavour to keep this blog updated with my experiences over the next 12 months, and try to translate what I have learnt (well, the interesting bits at any rate) into plain English.

And I hope that you will enjoy reading it.