Correlation between individual differences in striatal dopamine and in visual consciousness.

Abstract

A widely held view on consciousness is that it is related to the 'broadcasting' of sensory information to the whole brain [1-3]. Despite the fact that there is general support for this view, it remains unclear how exactly this broadcasting is established. It has been proposed [2,3] that thalamocortical circuits are an important mediator of such broadcasting, but empirical support for this claim is lacking. In the present study, we investigated this hypothesis by exploiting the well-established, but in this context neglected, fact that thalamocortical connectivity is modulated by dopaminergic activity in the striatum [4]. We used positron emission tomography (PET) to measure individual differences in striatal dopamine (DA) level and we correlated this with individual differences in visual consciousness. Our results show that visual awareness is related to the concentration of endogenous DA or DA receptors in striatal areas, supporting the importance of dopaminergic signalling in visual consciousness.