The Bernstein Center for Computational Neuroscience Freiburg

Announcement for the next
BCCN Seminar
Dr. Richard Hahnloser
Institut für Neuroinformatik
ETHZ Zurich
Neural sequence generation in a premotor area of the songbird
Thursday, November 30th, 2006
Lecture Hall (ground floor)
BCCN building
Hansastraße 9A
79104 Freiburg
Projection neurons in HVC of the songbird display sequential ultrasparse activity during singing. Little is known about the biophysical and circuit mechanisms underlying the generation and learning of such premotor activity. We perform in-vivo electrophysiological and pharmacological experiments as well as computer simulations to elucidate neural activity propagation in the HVC network. We find that different dynamics apply to song-related and sleep-related HVC neural sequences. During sleep, HVC activity is subject to a strong feedforward drive, whereas during singing the HVC sequences seem to be generated largely by intrinsic circuit mechanisms. In a simple model we find that random feedforward input to HVC neurons can induce ultrasparse sequence formation in the presence of a spike-time dependent learning rule and simple competition between growing synapses. The HVC circuit that emerges in our model is that of a synfire chain. We show that the benefit of ultrasparse HVC sequences could be to provide an optimized set of basis functions for the rapid learning of birdsong.
The talk is open to the public. Guests are cordially invited!