Watch out for modules

A posting on the Neuroskeptic blog (here) reminds us that various scanning methods create an image of the brain that we know is misleading. The picture we must avoid slipping into without good evidence is one where particular functions/processes in the brain are localized and somewhat isolated from others. The lovely coloured areas on scans are somewhat artificial. Research on the connections between neurons shows that cells that are quite distant from each other are connected and work together (see previous posting). Other research shows that quite distant neurons can fire in unison. The paper that Neuroskeptic writes about is one that looks at the prefrontal cortex and shows that is not as modular as it is assumed to be. The same networks within the prefrontal cortex can do various different work.

As far as our subject, consciousness, is concerned, it is clear that the production of consciousness involves much of the cortex and some lower brain areas engaging in synchronous activity. It is about as global and all inclusive an event as we can currently see in the brain. We do not know what is happening in consciousness but we do know that it is not confined to a particular region of the cortex. No diagram that labels a location for consciousness, a consciousness module, should be trusted.

Of course knowing where there is the most neural activity is a step towards understanding mental processes in general. At present that information is very coarse-grained in space and in time. It is only a step. It adds some clarity, but if it is taken too literally it can also make things less clear, especially for the general public.

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