In Hermissenda crassicornis, the memory of light associated with turbulence is stored as changes in intrinsic and synaptic currents in both type A and type B photoreceptors. These photoreceptor types exhibit qualitatively different responses to light and current injection, and these differences shape the spatiotemporal firing patterns that control behavior. Thus the objective of the study was to identify the mechanisms underlying these differences. The approach was to develop a type B model that reproduced characteristics of type B photoreceptors recorded in vitro, and then to create a type A model by modifying a select number of ionic currents. Comparison of type A models with characteristics of type A photoreceptors recorded in vitro revealed that type A and type B photoreceptors have five main differences, three that have been characterized experimentally and two that constitute hypotheses to be tested with experiments in the future. See paper for more and details.
Model Type: Neuron or other electrically excitable cell
Cell Type(s): Hermissenda photoreceptor Type A; Hermissenda photoreceptor Type B
Currents: I T low threshold; I A; I K; I h; I K,Ca; I Calcium
Model Concept(s): Activity Patterns; Invertebrate
Simulation Environment: Chemesis
Implementer(s): Blackwell, Avrama [avrama at gmu.edu]
References:
Blackwell KT. (2006). Ionic currents underlying difference in light response between type A and type B photoreceptors. Journal of neurophysiology. 95 [PubMed]