Slow depolarization produced by associative conditioning of Aplysia sensory neurons may enhance Ca2+ entry.

Sensory neurons activated by intracellular stimulation immediately before sensitizing tail shock displayed a slow depolarization after the shock. By contrast, sensory neurons exposed to the effects of tail shock alone or unpaired activation and tail shock showed a slow hyperpolarizing response to the shock. A voltage-sensitive Ca2+ conductance that is activated near the resting potential may be modulated by these opposite effects of associative and non-associative training.