Neural principles of associative learning

In order to understand the cellular learning mechanisms in the nudibranch mollusk Hermissenda crassicornis, a model of the type B photoreceptor cell including the dynamical aspects of the voltage-clamp recording system was formulated in the Hodgkin-Huxley-type equations in terms of each relevant ionic current: I/sub A/I/sub C/ and I/sub Na/. Measurements of these currents from conditional animals revealed that only I/sub A/ and I/sub C/ were substantially reduced across the soma of type B cell. The current model was effective in producing a quantitative estimation of the actual ionic currents. A computer simulation revealed that I/sub A/ was so sensitive to the parameters in the recording system that the divergence in the experimental data increased. This was further confirmed by using the triangular waveform as a command signal (+60 mV in amplitude from a holding potential of -60 mV).<>