Fig. 1.

Cortical and pallidal inputs to the thalamus. A and B: schematic of the avian song system. While songbirds do not have a mammalian-like layered neocortex, their pallium has homologous structures (referred to hereafter as cortical) (Jarvis 2004). Lateral magnocellular nucleus of the anterior nidopallium (LMAN) and HVC (proper name), area X, and DLM constitute the cortical, basal ganglia (BG), and thalamic portions of the anterior forebrain pathway (AFP). LMAN forms the output of the AFP through its projection to RA, a motor cortical (MC) nucleus, which in turn projects to motoneurons in the brain stem. C and D: confocal images of thalamic neurons in DLM (green) and inputs from a calyceal pallidal axon terminal (red; C) and RA axon terminals (blue; D).