The defensive siphon and gill withdrawal reflex of Aplysia is a simple reflex mediated by a well-defined neural circuit. This reflex exhibits classical conditioning when a weak tactile stimulus to the siphon is used as a conditioned stimulus and a strong shock to the tail is used as an unconditioned stimulus.

What is the process by which classical conditioning occurs in Aplysia?

The siphon withdrawal reflex also exhibits classical conditioning when a weak stimulus to the siphon or mantle shelf (the conditioned stimulus or CS) is paired with a shock to the tail (the unconditioned stimulus or US).

What is the Aplysia in psychology?

n. a genus of molluscs that have a very simple nervous system and are often used to study neurophysiology, especially the neurophysiology of learning and memory. [