Role of the cerebral ganglia in the organization of alimentary behavior of the pteropod mollusc Clione limacina.

The role of the cerebral ganglia in the switching of the behavior of a mollusc from free swimming to hunting behavior was studied. For this purpose the bodies of neurons providing processes to sensory and motor nerves were stained by means of retrograde axonal transport of Co2+ ions, and the behavioral reactions occurring during extracellular stimulation of particular regions of the ganglia were investigated. Comparison of the morphological data with the behavioral reactions showed that the cerebral neurons participate on the basis of sensory information in the switching of quiet swimming to one of three modes: hunting behavior (including the seizure of food), active avoidance, and passive-defensive behavior.