An Ultra Sparse Code Underlies the Generation of Neural Sequences in a Songbird

During singing and sleep, populations of neurons in premotor nucleus RA of the zebra finch produce a complex spatio-temporal sequence of bursts. The similarity of song-related and sleep-related spike trains suggests a common circuit mechanism for their generation. To examine the origin of complex burst sequences in RA, we have studied sleep-related activity in both nucleus RA and in nucleus HVc, the primary source of premotor input to RA.