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Bruchas, M.

Publications and source records attributed to Bruchas, M..

2 recordsLinked to original sources

Cold-induced hyperphagia requires AgRP-neuron activation in mice

To maintain energy homeostasis during cold exposure, the increased energy demands of thermogenesis must be counterbalanced by increased energy intake. To investigate the neurobiological mechanisms underlying this cold-induced hyperphagia, we asked whether agouti-related peptide (AgRP) neurons are activated when animals are placed in a cold environment and, if so, whether this response is required for the associated hyperphagia. We report that AgRP-neuron activation occurs rapidly upon acute cold exposure, as do increases of both energy expenditure and energy intake, suggesting the mere perception of cold is sufficient to engage each of these responses. We further report that silencing of AgRP neurons selectively blocks the effect of cold exposure to increase food intake. Together, these findings establish a physiologically important role for AgRP neurons in the hyperphagic response to cold exposure.

neuroscience

Prepronociceptin expressing neurons in the extended amygdala encode and promote rapid arousal responses to motivationally salient stimuli

Motivational states are complex and consist of cognitive, emotional, and physiological components controlled by a network across multiple brain regions. An integral component of this neural circuitry is the bed nucleus of the stria terminalis (BNST). Here, we identified a subpopulation of neurons within BNST expressing the gene prepronociceptin (PnocBNST), that can modulate the rapid changes in physiological arousal that occur upon exposure to stimuli with motivational salience. Using in vivo two-photon calcium imaging we found that excitatory responses from individual PnocBNST neurons directly corresponded with rapid increases in pupillary size and occurred upon exposure to both aversive and rewarding odors. Furthermore, optogenetic activation of these neurons increased pupillary size, but did not alter approach/avoidance or locomotor behaviors. These findings suggest that excitatory responses in PnocBNST neurons encode rapid arousal responses irrespective of tested behaviors. Further histological, electrophysiological, and single-cell RNA sequencing data revealed that PnocBNST neurons are composed of genetically and anatomically identifiable subpopulations that can be further investigated. Taken together, our findings demonstrate a key role for a PnocBNST neuronal ensemble in encoding the rapid arousal responses that are triggered by motivational stimuli.

neuroscience