The neural correlates of conscious experience: an experimental framework

Demonstrating that neural activity 'represents' properties of the world suc h as the orientations of a line in the receptive field of a nerve cell is a standard procedure in neuroscience. However, not all such neural activity will be associated with the mental representations that form the contents o f consciousness. In some cases, such as when patients with blindsight corre ctly 'guess' the location of a stimulus, neural activity is associated with physical stimulation and with appropriate behaviour, but not with awarenes s. To identify the neural correlates of conscious experience we need to ide ntify patterns of neural activity that are specifically associated with awa reness. Experiments aimed at making such identifications require that subje cts report some aspect of their conscious experience either verbally or thr ough some pre-arranged-non-verbal report while neural activity is measured. If there is some characteristic neural signature of consciousness, then th is should be distinguishable from the kinds of neural activity associated w ith stimulation and/or behaviour in the absence of awareness. It remains to be seen whether the neural signature of consciousness relates to the locat ion of the neural activity, the temporal properties of the neural activity or the form of the interaction between activity in different brain regions.