principles of behavioural neuroscience

In the current TLS, an excellent article by Tim Crane on neuroimaging, consciousness, and the mind-body problem. Many of my previous posts here related to this have endorsed a kind of mild neuro-scepticism, Crane begins his article by describing an experiment which should the literally expansive nature of neuroscience:

In 2006, Science published a remarkable piece of research by neuroscientists from Addenbrooke’s Hospital in Cambridge. By scanning the brain of a patient in a vegetative state, Adrian Owen and his colleagues found evidence of conscious awareness. Unlike a coma, the vegetative state is usually defined as one in which patients are awake – they can open their eyes and exhibit sleep-wake cycles – but lack any consciousness or awareness. To discover consciousness in the vegetative state would challenge, therefore, the basic understanding of the phenomenon.

The Addenbrooke’s patient was a twenty-three-year-old woman who had suffered traumatic brain injury in a traffic accident. Owen and his team set her various mental imagery tasks while she was in an MRI scanner. They asked her to imagine playing a game of tennis, and to imagine moving through her house, starting from the front door. When she was given the first task, significant neural activity was observed in one of the motor areas of the brain. When she was given the second, there was significant activity in the parahippocampal gyrus (a brain area responsible for scene recognition), the posterior parietal cortex (which represents planned movements and spatial reasoning) and the lateral premotor cortex (another area responsible for bodily motion). Amazingly, these patterns of neural responses were indistinguishable from those observed in healthy volunteers asked to perform exactly the same tasks in the scanner. Owen considered this to be strong evidence that the patient was, in some way, conscious. More specifically, he concluded that the patient’s “decision to cooperate with the authors by imagining particular tasks when asked to do so represents a clear act of intention, which confirmed beyond any doubt that she was consciously aware of herself and her surroundings”.

Owen’s discovery has an emotional force that one rarely finds in scientific research. The patients in the vegetative state resemble those with locked-in syndrome, a result of total (or near-total) paralysis. But locked-in patients can sometimes demonstrate their consciousness by moving (say) their eyelids to communicate (as described in Jean-Dominique Bauby’s harrowing and lyrical memoir, The Diving Bell and the Butterfly, 1997). But the vegetative state was considered, by contrast, to be a condition of complete unconsciousness. So to discover that someone in such a terrible condition might actually be consciously aware of what is going on around them, thinking and imagining things, is staggering. I have been at academic conferences where these results were described and the audience was visibly moved. One can only imagine the effect of the discovery on the families and loved ones of the patient.

Crane’s article is very far from a piece of messianic neurohype, but he also acknowledges the sheer power of this technology to expand our awareness of what it means to be conscious and human, and the clinical benefit that is not something to be sniffed at. But, it doesn’t solve the mind-body problem – it actually accentuates it:

Does the knowledge given by fMRI help us to answer Julie Powell’s question [essentially a restatement of the mind-body problem by a food writer]? The answer is clearly no. There is a piece of your brain that lights up when you talk and a piece that lights up when you walk: that is something we already knew, in broad outline. Of course it is of great theoretical significance for cognitive neuroscience to find out which bits do what; and as Owen’s work illustrates, it is also of massive clinical importance. But it doesn’t tell us anything about “how we can be”. The fact that different parts of your brain are responsible for different mental functions is something that scientists have known for decades, using evidence from lesions and other forms of brain damage, and in any case the very idea should not be surprising. FMRI technology does not solve the mind–body problem; if anything, it only brings it more clearly into relief.

Read the whole thing, as they say. It is a highly stimulating read, and also one which, while it points out the limits of neuroimaging as a way of solving the difficult problems of philosophy, gives the technology and the discipline behind it its due.

This piece is no longer actively on nthposition. Fortunately I had previously preserved a copy on a precursor of this blog, with an entertaining typo in the heading.

I ended up having some correspondence with Macmillan subsequently – specifically about the lyrics to the Slackdaddy song (although I don’t think he like the word “primly”) His book is availble here. I think this book marked a point where I began to exhibit a certain reserve and scepticism about similarly pat, anecdotal stories.

I find that Jackson Beatty’s book seems to be rather obscure – one of the textbooks from my medical education that was perhaps less directly helpful in getting me through exams but did help provide a good quote illustrating the Official Version of Gage’s story.

Review of “An Odd KinD of Fame: Stories of Phineas Gage” by Malcolm Macmillan

At 4.30pm on 13 September 1848, the foreman of a group of railway construction workers in Cavendish, Vermont, suffered a horrendous accident that secured his later role as one of the most famous patients in the history of medicine. Virtually all humanity – famous, unknown and infamous – were, are or will be patients at some stage, but Phineas Gage is among the select few whose fame rests entirely on their status as patients. Some of Freud’s cases – “Rat Man”, Judge Schreber, Anna O – are perhaps Gage’s main rivals of this score. But while Freud and all his works have been closely examined and hotly contested over the years, Malcolm Macmillan, Adjunct Professor in the School of Psychology at Deakin University in Australia, found in 1983 that while various stories of Gage’s accident were widely known, little detail was. As the blurb puts it “almost nothing is known about him, and most of what is written is seriously in error.”

For the reader who has never heard of Phineas Gage, and may well be rather sceptical about his fame, I give a typical extract from a modern textbook, in this case the 1996 edition of Principles of Behavioural Neuroscience by Jackson Beatty:

The importance of the cerebral hemispheres for emotion, and in particular the frontal lobes, was made strikingly clear over a century ago by the case of Phineas Gage, the foreman of a railroad crew who suffered a remarkable injury. An accidental explosion drove an iron rod into Gage’s cheek and out through the top of his skull. Miraculously he survived the injury but suffered a massive lesion of the frontal lobes. Before the accident, Gage was a model citizen and employee, but the frontal damage transformed his very character. Gage’s physician described the change as follows:
“The equilibrium or balance, so to speak, between his intellectual faculty and animal propensities, seems to have been destroyed. He is fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires, at times pertinaciously obstinate, yet capricious and vacillating, devising many plans of future operation, which are no sooner arranged that they are abandoned in turn for others- His mind was radically changed, so decidedly that his friends and acquaintances said that he was ‘no longer Gage'”

That’s the textbook version in neurology books, and such a striking story has naturally entered a wider consciousness. Macmillan gives many examples of the story’s use in documentaries, novels and other unexpected places. For example, in Roger Kimball’s The Long March: How the Cultural Revolution of the 1960s Changed America, the very first figure we encounter is Phineas Gage; based on a 1994 New York Times report, Kimball writes that “pondering the sad state of contemporary American cultural life, I have often recalled the sad story of Phineas Gage. Like him, our culture seems to have suffered some ghastly accident that has left it afloat but rudderless: physical intact, its ‘moral centre’ is a shambles.” On the morning of 13 September 1848, Gage would hardly have suspected he would be drafted into the culture wars of a century and a half later.

Macmillan even uncovers two rock bands called “Phineas Gage” and “Finneus Gauge”, and a song by Slackdaddy called “What’s the matter with Phineas Gage?”, of which he writes primly “although no one I know who has listened to the song has been able to understand more than a few words, the group neither seems to sing anything of significance about Gage nor to answer the question posed in the title of the song.”

There is no doubt that Gage suffered the accident, and that it had a dramatic effect on his life. Nevertheless, Macmillan shows, the account that has entered both scientific and popular discourse is flawed. Firstly, we know very little about Gage’s personality and habits before the accident, and secondly the after effects were not, contemporaneously, reported as being quite so dramatic.

Within twenty-four hours of the accident, a first report was (anonymously) printed in the Ludlow, Vermont Free Soil Union. Having described the accident, the paper reports that “the most singular circumstance connected with this melancholy affair is, that he was alive at two o’clock this afternoon, and in full possession of his reason, and free from pain.”

“Gage’s physician”, as cited (second-hand) by Beatty above, was Dr John Martyn Harlow. Harlow mentioned very few psychological changes in his initial report of 1848. Henry Bigelow, Professor of Surgery at Harvard, wrote in 1850 that Gage was “quite recovered in faculties of body and mind.” It was Harlow’s account of 1868 that began to introduce the changes; the passage Beatty cites is taken from this source. Later writers began to embellish even more, adding drunkenness, braggadocio, a vainglorious tendency to show off his wound as part of Barnum’s Traveling Exhibition and an utter lack of foresight where these were unmentioned by Harlow.

In 1848, Macmillan writes, there was strong resistance to the idea that function could be localised to any particular are in the brain. Bigelow’s verdict was a victory for advocates of localisation, implying that the frontal lobes served no particular purpose. By 1868 however localisation was beginning to hold sway, with Paul Broca’s work on localising language function to the left hemisphere. Macmillan shows how differing psychological and neurological theories shaped the presentation of Gage’s story.

Macmillan explicitly states that this is not intended as a work of postmodernist relativism. Rather he is simply arguing that the subsequent stories of Gage bore little relation to the original facts that were known about him. Harlow’s account is pretty much all we know about Gage, and it is important to separate it from the subsequent encrustation of myth.

Quite aside from the pressures of neurological debate, a number of other stories have clung to Gage. The various accounts of him showing off his wound in a tent on Boston Common and in Barnum’s circus seem to derived from a passing reference in Harlow’s 1869 report to Gage’s stay in New York at “Barnum’s, with his iron”, which Macmillan presumes must mean Barnum’s American Museum, and there is no evidence Gage toured with a circus.

As Macmillan writes, the textbook accounts of Gage are not wildly wrong. “If we divide the story into seven elements – rarely did a single account contain major errors in more than three of these elements”, and he finds that the more inaccurate textbooks seem to have depended on paraphrasing subsequent writers rather than Harlow’s report. This can be seen as a warning to authors in all disciplines to be wary of citing secondary sources routinely.

The story of Phineas Gage, as represented in the textbooks, is not a lie or a myth, but simply an exaggeration. Macmillan’s conclusion puts it best:

Vivid though Harlow’s description of Gage is, it is far from providing the detail we need for a full analysis of Phineas’ behaviour before and after the accident. That lack, together with the slightness of our knowledge of the specific locale and extent of the damage to his brain, provides too meagre a foundation on which to base hypotheses of the relation between the frontal lobes and their psychological functions- What has to be remembered is that his was the first case to point to a relation between brain an personality functions. That is its lasting importance.

Macmillan is exceedingly thorough and fair-minded in his approach. Some may even find the attention to detail excessive, with modern CT images of Gage’s skull, biographical chapters on Harlow, genealogical tables showing the lineage of Gage and Harlow. Macmillan, however, writes in a lively and accessible style. A book perhaps of interest only to a few, but nevertheless a fascinating example of how a medical case history “got legs”.