Finish analyses of effects of cutting the motor nerves to the syrinx on call parameters in newly-hatched chicks. Continue analysis of the efferents from the midbrain call region, comparing effects of activating lateral vs. medial (MLv vs. OM) structures on pontine and medullary call-related unit activity. I will spend three months in the Farmacologisch Laboratorium, University of Leiden, to learn the techniques that have been developed for differential characterization of two or more neural systems activated by a single stimulating electrode. Meanwhile we will be concentrating on ability of MCR to modulate those units that show call rhythms in their firing patterns or show respiratory rhythms in response to CO2. Analyze effects of archistriate, hyperstriate, and hypothalamic stimulation on multiunit activity in the midbrain call region, especially in the MLv. Begin study of activity of units in the midbrain call area (MLv) in awake, freely-moving hens using miniaturized radiotelemetry equipment (commercially available) to record multi-unit activity from the midbrain call region in a range of behavioral contexts. Continue studies of call-system anatomy by a) tracing degenerating fibers with reduced silver techniques from lesions in anterior hypothalamic regions where ESB turns on calling and from posterior sites where ESB inhibits ongoing vocalizing, and b) injecting H3-leucine into the same hypothalamic areas and determined by auto-radiography, to see how these areas connect into the midbrain-medullary call system that has already been identified.