The schematic summary illustrates the contribution of terminals that originate from the tree shrew striate cortex to synaptic circuits in the dorsal lateral geniculate (dLGN), pulvinar nucleus, and claustrum. Interneurons (I) and other elements that contain gamma amino butyric acid (GABA) are black. Thalamocortical and claustrocortical cells (relay cells, R), and other elements that are nonGABAergic, are gray. Circuits identified in the claustrum suggest an integration of convergent cortical inputs, gated by GABAergic circuits. See text for details.