Figure 7.

Hypothetical representation of a decision-making network and its regulation by operant learning in Aplysia. Left, the global circuit is composed of a pool of neurons (circles) that generate erratic and weakly coordinated impulse bursts (indicated by different shading intensities) as a result of specific intrinsic properties and pattern of connectivity. The network can generate different adaptive behaviors depending on the participation of individual neurons. Some cells contribute to common features of the different behaviors (neurons in the overlapping area), others contribute selectively to a single behavior (neurons in the non-overlapping areas). Behavioral occasion setting is at least in part governed by the variability in burst coordination in the former subset of neurons, while behavioral selection depends on burst recruitment/exclusion in the latter subset. Right, learning rigidifies network functioning by modifying synaptic connectivity and intrinsic bursting properties. As a result, coordinated bursting now reduces the variability in occasion setting and pattern selection, allowing the expression of a single stereotyped rhythmic behavior.