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.
A Medical Education 