Nonintralaminar thalamostriatal projections in the gray squirrel (Sciurus carolinensis) and tree shrew (Tupaia glis)

In mammals, the corpus striatum receives prominent projections from the neocortex and from the intralaminar nuclei of the dorsal thalamus. The present study provides evidence based on anterograde degeneration and axonal transport that the corpus striatum also receives input from two nonintralaminar thalamic nuclei, the pulvinar and the medial geniculate body. Each of these nuclei projects to a separate region of the corpus striatum. Moreover, the same regions of the corpus striatum that receive projections from the pulvinar and medial geniculate body also receive projections from the cortical targets of these nuclei.