Figure 1.

Schematic diagram of the human visual system. The main connections originating in the retina are represented in thick arrows. They synapse in the lateral geniculate nucleus (LGN) and project to the primary visual cortex (V1). V1 sent information to the extrastriate areas (V2, V3, V4 and MT+/V5). Most of the corticocortical (in blue) and subcortico-cortical (in orange) connections are reciprocal but are not represented for clarity of the schema. Alternative pathways are represented in thin arrows. The extrageniculostriate pathway belonging to the dorsal visual stream, originates in the retina and synapses in the superior colliculus (SC) and in the pulvinar and projects directly to extrastriate areas (in particular area MT+/V5) bypassing both V1 and the LGN. This pathway has been accounted to mediate action blindsight. Another colliculo-pulvinar pathway, associated with the ventral visual stream, synapses in the LGN and projects to extrastriate areas (in particular area V4) bypassing V1. This pathway has been accounted to mediate color and shape residual discrimination. Other collicular pathways are represented: the colliculo-pulvinar pathway (between SC and pulvinar), the pulvino-amygdalar pathway (between the pulvinar and amygdala) and the colliculo-pulvino-amygdalar pathway (between the SC, the pulvinar and the amygdala). These pathways have been accounted to mediate affective blindsight.