Biology subjects

Markovic, M.

Publications and source records attributed to Markovic, M..

2 recordsLinked to original sources

bioRxiv2018

Adaptive disinhibitory gating by VIP interneurons permits associative learning

Learning drives behavioral adaptations necessary for survival. While plasticity of excitatory projection neurons during associative learning is studied extensively, little is known about the contributions of local interneurons. Using fear conditioning as a model for associative learning, we find that behaviorally relevant, salient stimuli cause learning by tapping into a local microcircuit consisting of precisely connected subtypes of inhibitory interneurons. By employing calcium imaging and optogenetics, we demonstrate that vasoactive intestinal peptide (VIP)-expressing interneurons in the basolateral amygdala are activated by aversive events and provide an instructive disinhibitory signal for associative learning. Notably, VIP interneuron responses are plastic and shift from the instructive to the predictive cue upon memory formation. We describe a novel form of adaptive disinhibitory gating by VIP interneurons that allows to discriminate unexpected, important from irrelevant information, and might be a general dynamic circuit motif to trigger stimulus-specific learning, thereby ensuring appropriate behavioral adaptations to salient events.

neuroscience↗

bioRxiv2017

Central Amygdala Circuits Modulate Food Consumption Through A Positive Valence Mechanism

The complex behaviors underlying the pursuit and consumption of rewards are integral to an organisms survival. The hypothalamus and mesolimbic dopamine system are key mediators of these behaviors, yet regulation of appetitive and consummatory behaviors outside of these regions is not well understood. The central nucleus of the amygdala (CeA) is implicated in feeding and reward behavior, but the specific neural players and circuit mechanisms that positively regulate these behaviors remain unclear. Here, we define the neuronal mechanisms by which the CeA promotes consumption of food. We show, using in vivo activity manipulations and Ca2+ imaging, that CeA GABAergic neurons expressing the serotonin receptor 2a (Htr2a) modulate food consumption in multiple contexts, promote positive reinforcement and are active in vivo during eating. We demonstrate using electrophysiology, anatomical tracing methods and in vivo optogenetics that both intra-CeA and long-range circuit mechanisms underlie these functional effects. Finally, we show that CeAHtr2a neurons are poised to regulate food consumption through inputs from feeding-relevant brain regions. Our study highlights a mechanism by which defined CeA neural circuits positively regulate food consumption.

neuroscience↗