Modeling frequency encoding in the cricket cercal sensory system

The cercal sensory system of the cricket mediates the detection and analysis of low velocity air currents. Sensory stimuli are encoded as spatiotemporal patterns of activity within an afferent map that provides inputs to primary sensory interneurons. We have developed biophysically based interneuron models with synaptic inputs that are derived from a dynamic model of the afferent map activity. Using these models, we have studied the possible mechanisms for the frequency tuning of one type of interneuron in this system. Our results indicate that frequency preferences are primarily due to the passive electronic structure of the dendritic arbor and the dynamic sensitivity of the spike initiation zone.