  The means by which neuronal activity yields robust behavior is a ubiquitous
question in neuroscience. In the songbird, the timing of a highly stereotyped
song motif is attributed to the cortical nucleus HVC, and to feedback to HVC
from downstream nuclei in the song motor pathway. Control of the acoustic
structure appears to be shared by various structures, whose functional
connectivity is largely unknown. Currently there exists no model for functional
synaptic architecture that links HVC to song output in a manner consistent with
experiments. Here we build on a previous model of HVC in which a distinct
functional architecture may act as a pattern generator to drive downstream
regions. Using a specific functional connectivity of the song motor pathway, we
show how this HVC mechanism can generate simple representations of the driving
forces for song. The model reproduces observed correlations between neuronal
and respiratory activity and acoustic features of song. It makes testable
predictions regarding the electrophysiology of distinct populations in the
robust nucleus of the arcopallium (RA), the connectivity within HVC and RA and
between them, and the activity patterns of vocal-respiratory neurons in the
brainstem.
