Suprathreshold stochastic firing dynamics with memory in P-type electroreceptors

Weakly electric fish generate a periodic electric field as a carrier signal for active location and communication tasks. Highly sensitive P-type recep tors on their surface fire in response to carrier amplitude modulations (AM 's) in a noisy phase locked fashion. A simple generic model of receptor act ivity and signal encoding is presented. Its suprathreshold dynamics, memory and receptor noise reproduce observed firing interval distributions and co rrelations. The model ultimately explains how smooth responses to AM's are compatible with its nonlinear phase locking properties, and reveals how rec eptor noise can sometimes enhance the encoding of small yet suprathreshold AM's.