An in vitro analog of learning that food is inedible in Aplysia: decreased responses to a transmitter signaling food after pairing with transmitters signaling failed swallowing

Pairing histamine with a cholinomimetic reduces the response to the cholinomimetic alone. The first (panels 1; blue) and last (panels 2; red) exposures to CCh alone are shown. (A) Between the two exposures to CCh, the cerebral ganglion was treated with HA in ASW. (B) Between the two exposures to CCh alone, the ganglion was treated with CCh paired with HA. (BN2) Buccal nerve 2, (BN3) buccal nerve 3, (Rad N) radula nerve.