Durations of preparatory motor activity in the avian basal ganglia for songs and calls in a species of songbirds

Male songbirds are highly motivated to sing undirected song (US) as juveniles during song learning, and as adults. Given that singing US is a self-driven, elaborated behavior, we would expect to see preparatory activity in the striatal area prior to vocalization, and this preparatory activity could have different characteristics compared to activity driven by calls. In general, songs are longer, complex and influenced by learning while calls are shorter, simpler, and less influenced by experience. The present study recorded neural activity in Area X, a nucleus of the basal ganglia, in male Java sparrows (Lonchura oryzivora) in a sound-proof box and analyzed differences in activity change before US and trill-calls. Trill-calls were often emitted in social arousal, but oc-casionally emitted when alone. We saw a gradual increase in firing rate for about 2.3 s prior to the onset of US, and a shorter increase of about 1.3 s in firing rate prior to the onset of trill-calls. The results reveal that initiating US may be influenced by a prolonged and specific activity increase in the extent that is not seen with trill-calls. Results suggest that direct or indirect projections to Area X, which may reflect motivational state, could be the cause of this activity change.

Automated summary

This study found that male songbirds show a prolonged and specific increase in neural activity before initiating undirected song, which is not observed before trill-calls. The results suggest that motivational state could be the cause of this activity change in the context of undirected singing.