Crick's Theory - Synchronized and rhythmic electrical activity in networks of brain cells

This theory predominately aims to describe the intermediary pathway that may lead to the unified sense of self. The late Francis Crick, a Nobel Prize winner and the co-discoverer of DNA, and Christof Koch of the California Institute of Technology have proposed that a starting-point for the study of consciousness is the study of the correlates of visual consciousness, in other words the changes in brain-based biological processes when we are conscious of seeing things. Crick and Koch have argued that all the different aspects of consciousness (for example, pain, visual awareness, self-consciousness and so on) may employ a basic common mechanism or perhaps a few such mechanisms. Hence understanding and discovering the mechanism for one aspect may allow an understanding of the other aspects too.

Although Crick and Koch accept that it is difficult to account for how conscious experience arises from the activity of the brain, they propose that there must be some specific underlying differences in brain cell activity that lead to the phenomenon of consciousness. Thus they propose that in order to study visual consciousness it is important to identify the brain-based biological events that take place during visual consciousness and correlate them. It is hoped that these will ultimately help identify the specific mechanisms that lead to the phenomenon of visual awareness. Crick and Koch have observed that brain cells responsive to shape, colour and movement may become active in synchrony in the general range of 40 times per minute (40 Hertz). They suggest that maybe synchronized activation of brain cells in this range (roughly 40 times per minute, but perhaps as low as 35 and possibly as high as 75 times) might be how the brain puts together visual consciousness.

Furthermore, as an area of the brain called the thalamus appears to play a central role in mediating consciousness, and conscious experience also depends on the surface of the brain or the cortex, they suggest that consciousness may depend on synchronized firing in the range of 40 Hertz in the networks of cells connecting the thalamus and the cortex. This is sometimes called '40-Hertz oscillation'.

So, basically it is thought that this rhythmic and synchronized activity of neurones may be the neural correlate of awareness and might serve to bind together activity concerning the same object in different brain areas. At present, however, there is little experimental evidence to support this suggestion directly and it still does not account for how either the actual process of consciousness or the binding of consciousness arise.