Abstract
Song of passerine (like zebra finch) is a learned motor behavior which used by males to attract females and protect territories. Generally, bird song is consists of several different song notes (elements), and order of these notes is stereotyped. Among the passerine birds, however, male Bengalese finches (Lonchura striata var. domestica; BF) sing complex song which follows finite state syntax. The song control system in the forebrain of songbird consists of a set of discrete nuclei include HVC, RA, Area X, NIf and LMAN. In this study, we injected neural tracers (dexstran amines) in 3 song nuclei (HVC, RA and Area X) to elucidate the input-output connections and local circuitry (cyto-architecture) of HVC. Result shows that HVC receives input from Field L and NIf, and it sends axons to RA (analog of mammalian primary motor cortex that innervates nXII and DM) and Area X (analog of basal ganglia). We observed that 3-5 middle to large sized neurons formed clusters in HVC, and these clusters were distributed dispersedly throughout the nucleus. Most of the clusters innervated both RA and Area X. We also recorded neural responses to bird's own song (BOS) in HVC of BF by 1-3 tetrodes. Clustered multi-neuron activities were synchronized to temporal structure of BOS. This result suggests that the finite state syntax of complex bird song represent dispersedly in HVC. [Jpn J Physiol 54 Suppl:S209 (2004)]
