Regulation of androgen on singing behavior and song control system of songbirds / 生理学报

Androgen plays an important role in singing of songbirds. Recent studies have shown that androgen levels in vivo not only affect the external morphology of songbirds, but also affect their singing behavior. Androgens (including derivatives) affect singing behavior and singing system in many ways. Based mainly on the results from our research group in the zebra finch, this review summarizes the effects of androgen on singing behavior, excitability and synaptic transmission of projection neurons of singing system, and the interaction of androgen with other neurotransmitter receptors in the brain of songbirds.

Central cholinergic system innervates song control system of songbirds and regulates song behavior / 生理学报

Songbird has become an ideal model for studying motor learning due to its unique learned song behavior. It has been proved that song behavior is directly regulated by song control system in the forebrain of songbirds. There are lines of evidence to show that cholinergic transmitters and their receptors are distributed in song control system, and vocal control nuclei in song control system are innervated by cholinergic nerves from the central cholinergic system in basal forebrain, which can affect activities of vocal control nuclei through cholinergic transmitters, and then affect song behavior. Studies in mammals have confirmed that the central cholinergic system is involved in the regulation of motor behavior and neural process of motor learning. Elucidation of regulation of songbirds' song behavior by central cholinergic system would shed light on the neural mechanism of song motor control and song learning and memory in songbirds, and provide theoretical insights for researches on other animals' sensorimotor processes and human language learning. This review summarized recent progresses, including the research work of our laboratory, in the studies on the selectivity of cholinergic transmitters to their receptors and their effects on neuronal activities in vocal control nuclei of songbirds and provided valuable clues for revealing the regulation mechanism of central cholinergic system on songbirds' song behavior.

Effects of androgens on the long-term depression of HVC-RA pathway in adult male zebra finches / 生理学报

Androgens can affect the singing behavior via regulating the song control system. In the present study, the effect of androgen on the synaptic plasticity of high vocal center (HVC)-robust nucleus of the arcopallium (RA) pathway was investigated through electrophysiological recording in vivo. We divided the adult male zebra finches into control, castration and castration plus testosterone implantation groups. The changes of long-term depression (LTD) and the paired-pulse facilitation in HVC-RA pathway induced by high-frequency (400 Hz, 2 s) stimulation of HVC were recorded, respectively. The results showed that high-frequency stimulation could effectively induce LTD in control group, but only evoke short-term depression in the castration group. In castration plus testosterone implantation group, LTD was restored. The paired-pulse facilitation was not obvious in the castration group, whereas it was significantly improved in the control and castration plus testosterone implantation groups. These results suggest that androgens may maintain the stability of song by influencing the level of LTD in HVC-RA pathway in adult male zebra finches, and androgens can affect the short-term synaptic plasticity of HVC-RA pathway.