Model of song selectivity and sequence generation in area HVc of the songbird.
In songbirds, nucleus HVc plays a key role in the generation of the syllable sequences that make up a song. Auditory responses of neurons in HVc are selective for single syllables and for combinations of syllables occurring in temporal sequences corresponding to those in the bird's own song. We present a model of HVc that produces syllable- and temporal-combination-selective responses on the basis of input from recorded bird songs filtered through spectral temporal receptive fields similar to those measured in field L, a primary auditory area. Normalization of the field L outputs, similar to that proposed in models of visual processing, plays an important role in the generation of syllable-selective responses in the model. For temporal-combination-selective responses, N-methyl-d-aspartate (NMDA) conductances provide a memory that allows inhibitory neurons to gate responses to a final syllable in a sequence on the basis of responses to earlier syllables. When the same network that produces temporal-combination-selective responses is excited by a nonspecific timing signal, it generates a similar pattern of output as it does in response to auditory song input. Thus the same model network can perform both sensory and motor functions.
Drew
Patrick J
PJ
Volen Center for Complex Systems and Department of Biology, Brandeis University, Waltham, Massachusetts 02454-9110, USA. drew@brandeis.edu
Abbott
L F
LF
D000465:Algorithms; D000818:Animals; D001921:Brain / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D008959:Models, Neurological; D009431:Neural Conduction / Q000502:physiology; D016571:Neural Networks, Computer; D009474:Neurons / Q000502:physiology; D018091:Receptors, AMPA / Q000502:physiology; D018079:Receptors, GABA / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D020308:Songbirds / Q000502:physiology*; D014828:Vocalization, Animal / Q000502:physiology*
D018091:Receptors, AMPA; D018079:Receptors, GABA; D016194:Receptors, N-Methyl-D-Aspartate