A biophysical model of frequency-sweep selectivity in primary auditory cortex

Cells in primary auditory cortex respond preferably to frequency sweeps of a certain rate and direction. In a model by Fishbach et al. [J. Neurophysiol. 90 (2003) 3663–3678], direction selective cells emerged through patterned thalamocortical projections. The thalamic inputs to the auditory cortex were modeled as time-varying firing rates without explicit spikes. We investigate the biophysical constraints for the emergence of direction selectivity using a model that includes spiking thalamic neurons. We find that directional selectivity can still be achieved for a broad range of parameter values using an architecture similar to that proposed previously for visual cortex models. Furthermore, recurrent connections could improve the directional selectivity of the neurons.