[Neurophysiologic changes and bound calcium dynamics during the elaboration of associative learning in Helix lucorum]

Neurophysiological effects and dynamics of bound calcium (Ca-b) in command neurons of defense behavior (LP11 and RP11) during food aversion conditioning were studied in snail Helix lucorum. It was found that during associative learning both conditioned reaction and nonspecific facilitation of sensory responses were determined in neurons. The nonspecific facilitation of sensory responses was similar to that found during sensitization development in neurons. However, conditioned response appeared 30 min later than long-term sensitization development. Specific dynamics of the Ca-b level in neurons was obtained after three and more conditioning. The dynamics of the Ca-b level correlated with neurophysiological effects and differed from those measured during sensitization development. It is suggested that molecular mechanisms underlying associative learning and sensitization are different in a command neuron of defense behavior in the snail.