Multicompartment simulations of NMDA receptor-based facilitation in insect visual neurons

The development of tools for multicompartment simulations of a class of insect visual neuron is described. These include a system for converting morphological neural data in the Southampton Archive format into statements for the electrical simulation environment SPICE. The subject neurons, wide-field Small Target Motion-Detector cells, display strong selectivity for small moving visual objects, and also show evidence of response facilitation as stimuli move along spatially continuous tracks. We speculate that this facilitation is related to reliability of detection. We describe preliminary efforts to model the effect biophysically using the nonlinear characteristics of a class of excitatory synaptic receptors, the NMDA receptors.