Cellular Mechanisms of Calcium Elevation Involved in Long Term Memory

Hermissenda crassicornis is a shell-less marine snail that can be classically conditioned to associate light (the conditioned stimulus) with turbulence (the unconditioned stimulus). Acquisition of the association is critically dependent on elevation of intracellular calcium in the B cell soma, the location of memory storage. The source of calcium elevation has implications for cellular mechanisms underlying memory storage. To investigate sources of calcium elevation, a model of calcium dynamics in the photoreceptor was developed. Mechanisms of calcium diffusion, buffering and light activated release from intracellular stores were included in the model. Simulations show that release of calcium from intracellular stores is a significant source of calcium in the soma and may be the activating signal for the light-induced potassium current.