the small ventral region of the ventral posteromedial nucleus of thalamus in which the fibers of the gustatory lemniscus and secondary trigeminal tracts terminate; it projects to the lower part of the postcentral gyrus of the cerebral cortex. Syn: arcuate nucleus(1), nucleus arcuatus thalami, nucleus arcuatus, semilunar nucleus of Flechsig, thalamic gustatory nucleus.