Molecular-cellular mechanisms of learning of the common snail.

The development of sensitization and an associative habit of rejection of a specific type of food is accompanied by short-term and long-term changes in behavior, bioelectrical activity, and the dynamics of the content of Ca(b) in the command neurons of defense behavior of the common snail. In approximately an hour from the moment of the beginning of training, behavioral and neurophysiological effects which were similar on the whole were identified during the development of these habits. During the development of sensitization, the responses to test tactile stimulations and to applications of quinine and carrot juice appeared and/or were markedly intensified from 50 through 90 min from the moment of the first sensitizing stimulation. During the development of conditioning, responses to the tactile stimulations and quinine also appeared and/or intensified from 50-60 min, while responses to the conditional stimulus appeared and intensified approximately 30 min later (from 85-95 min). Phases of an initial marked increase, with a subsequent tendency to stabilization, in the level of Ca(b) were observed in the command neurons during a brief period in the development of sensitization; during conditioning a temporary decrease was identified in the content of Ca(b) in response to each combination of stimuli with its subsequent spontaneous decrease at 40-60 min. An increase in the level of Ca(b), beginning during the development of sensitization from 50-60 min, and during conditioning from 85-90 min from the moment of the beginning of training, was observed in the long-term period.(ABSTRACT TRUNCATED AT 250 WORDS)