Mathematics Colloquium: Stability of Adaptive Sensory Processing in Mormyrid Electric Fish
4:10 p.m. Neill 5W
Abstract: Many sensory systems adapt to repeated stimuli in order to ignore predictable sensory patterns and emphasize novel experience. An experimentally tractable sensory system that exhibits sensory adaptation is the electrosensory system of mormyrid electric fish. Electrosensory adaptation has been shown to rely on spike-timing dependent synaptic plasticity where the change in synaptic strength is dependent on the exact relative timing of pre-postsynaptic spikes. In this talk, we will use a mathematical representation of the electrosensory system to show that the particular synaptic learning rule found in this system drives the output to a stable equilibrium that cancels predictable stimuli. Conditions will be derived that insure that the equilibrium is not just locally, but globally asymptotically stable. An extended version of the model will then be introduced where the equilibrium is controlled by a feedback mechanism. The results suggest that the hypothesized mechanism for control of the electrosensory system's output would generate a stable cancellation of expected sensory patterns.