Retrograde HRP demonstration of afferent projections to the midbrain and nest calls in the ring dove.

Midbrain control of vocalization was evaluated in the ring dove by determining the major afferent inputs with retrograde tract tracing technique. Horseradish peroxidase was infused into various portions of the nucleus intercollicularis, an estrogen concentrating area, which disrupts nest calls when lesioned and induces the vocalization when stimulated by estrogen. Most labelled cell bodies were found in the archistriatum, including a region homologous to the mammalian amygdala.