Thalamic Control of Visual Attention

This chapter discusses thalamocortical interactions, an understanding of which is central to understanding perception and cognition. The visual thalamus consists of three main nuclei: the lateral geniculate nucleus (LGN), the thalamic reticular nucleus (TRN), and the pulvinar. The LGN is the thalamic station in the retinocortical projection and has traditionally been viewed as the gateway to the visual cortex. The TRN forms a thin shell of neurons surrounding the thalamus and providing an interface between the thalamus and cortex in that thalamocortical and (layer 6) corticothalamic projections also have collateral branches to the TRN. The pulvinar is a large nucleus located in the dorsal thalamus. It contains several visual maps that are reciprocally connected to striate and extrastriate cortex, in addition to being substantially interconnected with frontal and parietal cortex.