SATTERLIE, R.A.; Univ. of North Carolina, Wilmington: In the Mood: Neurobiological Characteristics of Motivational State and Arousal in a Pteropod Mollusk

Complex behavioral responses frequently depend on a combination of internal variables and external incentives that collectively contribute to modulatory influences that are referred to by many names: motivational state, drive, arousal, urge, impulse, mood, selective attention. While such behavioral states have been well characterized using psychological and behavioral approaches, neurophysiological testing of proposed conceptual characteristics, and roles in modulation of behavioral hierarchies, have not been as complete. The pteropod mollusk Clione limacina allows such investigation and provides evidence for a distinction between motivational states and arousal at the neurobiological level. In general, a motivational state is an altered behavioral condition that is designed to address a homeostatic imbalance or a physiological need. In Clione, a dramatic and experimentally tractable motivational state is involved in food acquisition and feeding behavior. Arousal is a more general modulatory state that provides either up-regulation or down-regulation of a variety of behaviors, without the specificity of a motivational state. In fact, arousal systems can contribute to specific motivational states. Work on Clione suggests that arousal systems, such as a well-characterized serotonergic system, are multifunctional and modular in construction. Modules can operate singly or in variable combinations to influence different behaviors.