Biology subjects

Fermani, F.

Publications and source records attributed to Fermani, F..

5 recordsLinked to original sources

bioRxiv2024

Food and water uptake are regulated by distinct central amygdala circuits revealed using intersectional genetics

The central amygdala (CeA) plays a crucial role in defensive and appetitive behaviours. It contains genetically defined GABAergic neuron subpopulations distributed over three anatomical subregions, capsular (CeC), lateral (CeL), and medial (CeM). The roles that these molecularly- and anatomically-defined CeA neurons play in appetitive behavior remain unclear. Using intersectional genetics, we found that neurons driving food or water consumption are confined to the CeM. Separate CeM subpopulations exist for water only versus water or food consumption. In vivo calcium imaging revealed that CeMHtr2a neurons promoting feeding are responsive towards appetitive cues with little regard for their physical attributes. CeMSst neurons involved in drinking are sensitive to the physical properties of salient stimuli. Both CeM subtypes receive inhibitory input from CeL and send projections to the parabrachial nucleus to promote appetitive behavior. These results suggest that distinct CeM microcircuits evaluate liquid and solid appetitive stimuli to drive the appropriate behavioral responses.

neuroscience↗

bioRxiv2024

Molecular and neural mechanisms of behavioural integration in the extended-amygdala

Integration of diverse stimuli is crucial for organisms to adapt and communicate effectively, enabling overall homeostasis and survival. Studies have been performed on identifying specific neuronal encoding of individual behaviours, but how neurons integrate diverse behaviours across contexts remains elusive. Here we use Ca2+ imaging in freely moving mice to identify neural ensembles in the extended amygdala encoding behaviours across six distinct contexts. We found extensive flexibility in these ensemble encodings that may act as reserves for behavioural integration, with those encoding aversive stimuli showing greater specificity. Finally, we identified differential gene expression profiles between ensembles that are enriched in associations with human psychiatric and neurodegenerative disorders. Overall, our results demonstrate the molecular mechanisms behind behavioural integration, and their potential implications in health and disease.

neuroscience↗

bioRxiv2022

Transcriptomics reveals amygdala neuron regulation by fasting and ghrelin thereby promoting feeding

The central amygdala (CeA) consists of numerous genetically-defined inhibitory neurons that control defensive and appetitive behaviors including feeding. Transcriptomic signatures of cell types and their links to function remain poorly understood. Using single-nucleus RNA-sequencing, we describe nine CeA cell clusters, of which four are mostly associated with appetitive and two with aversive behaviors. To analyze the activation mechanism of appetitive CeA neurons, we characterized Serotonin receptor 2a (Htr2a)-expressing neurons (CeAHtr2a) that comprise three appetitive clusters and were previously shown to promote feeding. In vivo calcium imaging revealed that CeAHtr2a neurons are activated by fasting, the hormone ghrelin, and the presence of food. Moreover, these neurons are required for the orexigenic effects of ghrelin. Appetitive CeA neurons responsive to fasting and ghrelin project to the parabrachial nucleus (PBN) causing inhibition of target PBN neurons. These results illustrate how the transcriptomic diversification of CeA neurons relates to fasting and hormone-regulated feeding behavior. HighlightsTranscriptomics reveals four appetitive, two aversive and three unknown CeA clusters Ghrelin and fasting activate CeAHtr2a neurons comprising three appetitive clusters Ghrelins orexigenic effects require the activity of appetitive CeA neurons CeA[->]PBN inhibition is necessary for ghrelin/fasting induced feeding

neuroscience↗

bioRxiv2022

Tripartite extended amygdala - basal ganglia CRH circuit drives arousal and avoidance behaviour

An adaptive stress response involves various mediators and circuits orchestrating a complex interplay of physiological, emotional and behavioural adjustments. We identified a population of corticotropin-releasing hormone (CRH) neurons in the lateral part of the interstitial nucleus of the anterior commissure (IPACL) - a subdivision of the extended amygdala, which exclusively innervate the substantia nigra (SN). Specific stimulation of this circuit elicits arousal and avoidance behaviour contingent on CRH receptor 1 (CRHR1) located at axon terminals in the SN, which originate from external globus pallidus (GPe) neurons. The neuronal activity prompting the observed behaviour is shaped by IPACLCRH and GPeCRHR1 neurons coalescing in the SN. These results delineate a novel tripartite CRH circuit functionally connecting extended amygdala and basal ganglia nuclei to drive arousal and avoidance behaviour. One-Sentence SummaryBrain centres involved in emotional and motor control are connected through a stress peptide promoting arousal and avoidance behaviour

neuroscience↗

bioRxiv2020

Encoding of environmental cues in central amygdala neurons during foraging

In order to successfully forage in an environment filled with rewards and threats, animals need to rely on familiar structures of their environment that signal food availability. The central amygdala (CeA) is known to mediate a panoply of consummatory and defensive behaviors, yet how specific activity patterns within CeA subpopulations guide optimal choices is incompletely understood. In a paradigm of appetitive conditioning in which mice freely forage for food across a continuum of cues, we find that two major subpopulations of CeA neurons, Somatostatin-positive (CeASst) and protein kinase C{delta}-positive (CeAPKC{delta}) neurons can assign motivational properties to environmental cues and encode memory of goal location. While the proportion of food responsive cells was higher within CeASst than CeAPKC{delta} neurons, only the activities of CeAPKC{delta}, but not CeASst, neurons were required for learning of contextual food cues. Since CeAPKC{delta} neurons are known to promote a range of defensive behaviors, our findings point to a model in which CeA circuit components are not organized in specialized functional units but can process both aversive and rewarding information in a context and experience dependent manner. HIGHLIGHTSTwo populations of central amygdala (CeA) neurons, CeAPKC{delta} and CeASst neurons can assign motivational properties to environmental cues and encode memory of goal location. The proportion of food responsive cells was higher among CeASst, than CeAPKC{delta} neurons. The activities of CeAPKC{delta}, but not CeASst, neurons are required for learning of contextual food cues. CeAPKC{delta} neurons represent a "general encoding" population selecting defensive and appetitive responses depending on context.

neuroscience↗