Neuroscience
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The medial nucleus of the amygdala (MeA) is known to regulate social behavior. This brain area is functionally positioned in a crossroads between sensory information processing and behavioral modulation. On the one hand, it receives direct chemosensory input from the accessory olfactory bulb. ⋯ However, the induction of gamma rhythmicity, thought to reflect activity of local neuronal networks, was significantly higher in rats than mice. Nevertheless, in contrast to rats, mice exhibited induction of rhythmicity, in both the theta and gamma bands, in synchrony with investigation of social, but not object stimuli. These results suggest that during interaction with a novel same-sex conspecific, the MeA of C57BL/6J mice is mostly involved in sensory information processing while in SD rats it is mainly active in modulating the social motivation state of the animal.
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The palatability and concentration of sweet foods promote hedonic feeding beyond homeostatic need. Understanding how neurons respond to sweet taste is thus of great importance. The dorsomedial nucleus accumbens shell (dNAcMed) is considered a "sensory sentinel," promoting hedonic feeding. ⋯ Importantly, in a Brief Access Taste Task, calcium responses for D1 and D2 exhibit much more heterogeneity than during a freely licking task. Specifically, D1 and D2 neurons form distinct ensembles: some ramp up in anticipation of the first lick, some respond at the end of the taste-access period, and some categorize sucrose concentrations as low or high. Collectively, NAcLat D1 and D2 neurons are organized in ensembles that adapt to the behavioral context to monitor task-relevant events and sucrose concentrations.
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Characterizing the functional involvement of specific brain regions has long been a central challenge in cognitive neuroscience. Functional magnetic resonance imaging (fMRI) techniques have offered solutions for mapping functional neural networks. The complex nature of structure-function correspondence makes an elaborate task design difficult to fully capture higher-order cognitive function. ⋯ Just like looking up a "coordinate-based cognition dictionary", researchers can receive a plethora of related tb-fMRI activation information characterized by cognitive domains, specific cognitive functions, cognitive task paradigms, and related publications. Surprisingly, we found that only less than 1% of brain-behavior association or between-group comparison studies have utilized this dictionary approach. We encourage the community to further engage with the existing databases for specific and comprehensive interpretation of neuroimaging as well as guidance of future experimental tb-fMRI design.
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Alterations in cognitive functions, social behaviors and stress reactions are commonly diagnosed in chronic mental illnesses (CMI). Animal models expressing mutant genes associated to CMI represent either rare mutations or those contributing only minimally to genetic risk. Non-genetic causes of CMI can be modeled by disturbing downstream signaling pathways, for example by inducing protein misassembly or aggregation. ⋯ Additionally, there was a trend towards increased corticosterone levels after restraint stress in the tgDISC1 rats. Our findings suggest that DISC1 protein misassembly leads to disturbances of cognitive flexibility and social behaviors, and might also be involved in stress sensitization. Since the observed behavioral features resemble symptoms of CMI, the tgDISC1 rat may be a valuable model for the investigation of cognitive, social and - possibly - also stress-related symptoms of major mental illnesses.