Learning and memory in invertebrates: Limax

The terrestrial mollusk Limax maximus possesses a highly developed learning ability to associate olfactory cues with both aversive and appetitive consequences. The learning mechanism is instantiated in a unique neural circuit, located in the procerebral (PC) lobe, which displays both oscillatory dynamics and wave propagation along its apical-basal axis. The cellular components of the PC lobe circuit and their biophysical properties have been identified. As is typical of higher neural centers, they contain a multitude of both fast acting and modulatory neurotransmitters that participate in the neural computations involving olfactory information in the PC lobe. Notable among these is the gaseous neurotransmitter nitric oxide, whose action is essential for implementing the oscillatory dynamics and the synaptic plasticity underlying odor learning.