Fig. 1.

Single-unit recording in the auditory and vocal motor pathways of the songbird brain. A: auditory and motor pathways of the song system intersect at the sensorimotor nucleus HVC. B: paired multiunit neural activity from NCM and HVC in response to stimuli (CON, conspecific song; BOS, bird’s own song; REV, reverse BOS). Note the high selectivity for BOS in HVC and the lack of strong selectivity in NCM. C: sorted single units from NCM, with examples of average waveforms and 100-waveform overlays (left and right) and PCA clusters (center). D: neurons in our recorded population of NCM show a unimodal distribution for spike quarter widths (SQW). E: rasters and peristimulus time histograms of activity in NCM and HVC during BOS stimulus playback across 3 retrodialysis treatment conditions. CM, caudal mesopallium; Ov, nucleus ovoidalis; RA, robust nucleus of the arcopallium.