Figure 2.

Schematic summary of some connections of the non-lemniscal auditory thalamus. The red pathway depicts a potential information-bearing route linking cortical areas via a corticothalamocortical pathway originating in layer 5 of a lower cortical area (AI), synapsing in a higher-order thalamic nucleus (D), and projecting to layer 4 of a higher cortical area (AII). The same layer 5 CT neurons may also branch to innervate lower motor centers. This pathway is distinct from the more numerous direct corticocortical connections that link many auditory areas, such as AI and the posterior auditory field (PAF), depicted by the orange pathway. A complementary system, putatively involved in affective processing of auditory information and synchronizing activity across cortical territories, is depicted by the blue pathway, which has widespread terminations in layer 1 of multiple areas and the amygdala (Amy). Omitted from the figure for simplicity are the projections of the medial division to layer 6 and also feedback CT projections originating in layer 6 of each area.