Session 2B: Symposium on “Neurocircuits Governing Behavior”

Neuropeptides in Generating Stable Innate States: Modulating the Feeding Drive

Innate states drive survival behaviours, though their neural implementation is poorly understood. Mechanisms mediating switching between alternative circuit states are critical for behaviour selection, while behavioural stability depends on the maintenance of reconfigured innate states. In the context of the feeding drive, internal energy demands drive the reconfiguration of neuronal circuits to adaptively regulate feeding behaviour. Energy state-dependent neuropeptide release from interoceptive neurons can signal energy status to feeding-associated circuits and modulate circuit function. The neuropeptides CART and NPY are major anorexic and orexic factors, respectively, but the intracellular signalling mechanisms utilized by these peptides to alter circuit function remain uncharacterized.
Using a zebrafish model, we show that glucose-responsive peptidergic neurons of the hypothalamus and ventral telencephalon converge onto the dorsomedial telencephalon (Dm) and modulate its activity by antagonistic CART and NPY signalling. In addition, CART-induced positive feedback temporally extends the hyperexcitable state of the Dm neurons, resulting in temporally stable changes in the feeding drive. These studies reveal novel modes of circuit modulation critical for homoeostasis and the generation of stable behavioural outcomes.