抄録
Songs of passerine birds (like zebra finch) are learned motor behavior which used by males to attract females and to protect territories. Generally, bird songs are consist of several different song notes (elements), and these notes are produced in a fixed temporal order. Among the passerine birds, male Bengalese finches (BF) sing complex song which follows finite state syntax. The song control system of BF consists of a set of discrete nuclei including the HVC, RA and Nif. Previous lesion study (Hosino and Okanoya 2000) showed that Nif lesioned BFs sung simpler songs, with less phrases to phrases branching than that of prelesion birds. This finding suggests that Nif-HVC connection plays important role in generating song grammar in BFs. In this study, we perfused Nif with muscimol (GABA agonist) for 30 minutes via microdialysis probes as a perturbation on Nif-HVC system. Following a local administration of muscimol into Nif, song grammar of BF was modified. Some of chunks in their finite state grammar disappeared and pronounced elongation of introductorily notes' duration was observed in first 3 hours. In addition, we also recorded stuttering like repetitions of song notes. Nif is also known as one of auditory relay nucleus to HVC. Some of drug effects, therefore, are possibly caused by disruption of auditory feedback. Further detailed studies are needed to know function of Nif-HVC connection in relating to generate song grammar. [J Physiol Sci. 2006;56 Suppl:S98]
