Project description:Social play is a frequently studied behavior and it is the most characteristic form of social interaction observed in adolescent rats. Social play is necessary for adolescents to develop proper cognitive, emotional, and social competency. Deficits in social play have been observed in several neurodegenerative disorders such as autism, schizophrenia, and attention deficit hyperactivity disorder. However, the information available on neural substrates and the mechanism involved in social play is still limited. This study characterized social play by proteomic and transcriptional profiling studies. Social play was performed on male Sprague Dawley rats on postnatal day 38 and protein and gene expression in the amygdala was determined following behavioral testing. The proteomic analysis led to the identification of 170 differentially expressed proteins (p≤0.05) with 67 upregulated and 103 downregulated proteins. The transcriptomic analysis led to the identification of 188 genes (adjusted p≤0.05) with 55 upregulated and 133 downregulated genes. Based on both protein and gene expression data, DAVID analysis revealed that social play altered neurotransmitter signaling including GABAergic and glutamatergic signaling and G-protein coupled receptor (GPCR) signaling. These data suggest that the synaptic levels of GABA and glutamate increased during play. Ingenuity Pathway Analysis (IPA) confirmed these alterations. IPA also revealed that differentially expressed genes/proteins in our data had significant over representation of additional neurotransmitter signaling systems, including the opioid, serotonin, and dopamine systems, suggesting that play alters the systems involved in the regulation of reward. In addition, corticotropin-releasing hormone signaling was altered indicating that an increased level of stress occurs during play. Our data suggest that increased inhibitory GPCR signaling in these neurotransmitter pathways occurs following social play as a physiological response to regulate the induced level of reward and stress and to maintain the excitatory-inhibitory balance in the neurotransmitter systems.
Project description:Social play was performed on one cohort of adolescent rats. Other cohort was remaining naïve to behavioral testing. The rats were scarified following behavioral testing on postnatal day 38. Amygdala was isolated form the brain, homogenized the tissue, proteins were quantified, trypsin digested, and analyzed by LC ESI MS/MS.
Project description:Social isolation poses a severe mental and physiological burden on humans. Most animal models that investigate this effect are based on prolonged isolation, which does not mimic the milder conditions experienced by people in the real world. Here we show that in the medial amygdala, a brain structure that is crucial for social memory, acute social isolation causes social memory loss and significant changes in specific mRNAs and proteins.
Project description:In humans, mutations in the transcription factor encoding gene, FOXP2, are associated with language and Autism Spectrum (ASD) Disorders, the latter characterized by deficits in social interactions. However, little is known regarding the function of Foxp2 in male or female social behavior. Our previous studies in mice revealed high expression of Foxp2 within the medial subnucleus of the amygdala (MeA), a limbic brain region highly implicated in innate social behaviors such as mating, aggression, and parental care. Here, using a comprehensive panel of behavioral tests in male and female Foxp2+/- heterozygous mice, we investigated the role Foxp2 plays in MeA-linked innate social behaviors. We reveal significant deficits in olfactory processing, social interaction, mating, aggressive and parental behaviors. Interestingly, some of these deficits displayed in a sex-specific manner. To examine the consequences of Foxp2 loss of function specifically in the MeA, we conducted a proteomic analysis of microdissected MeA tissue and found sex differences in a host of proteins implicated in neuronal communication, connectivity and dopamine signaling. Consistent with this, we discovered that MeA Foxp2-lineage cells were responsive to dopamine with differences between males and females. Thus, our findings reveal a central and sex-specific role for Foxp2 in social behavior and MeA function.
Project description:Innate social behaviors, such as mating and fighting, are fundamental to animal reproduction and survival. However, social engagements are associated with risks for the individual, such as pathogenic infection and physical injury. Little is known about the neural mechanism that allows for appropriate risk assessment and the suppression of hazardous social interactions. We have identified the posteromedial nucleus of the cortical amygdala (COApm) as a locus required for the suppression of mating with an unhealthy female and aggressive behaviors towards a dominant male intruder. Using anatomical tracing, functional imaging, and circuit-level epistatic analyses, we show that suppression of social engagements is mediated by the COApm projections onto the glutamatergic population of the medial amygdalar nucleus (MEA). We further show that this projection that governs social engagements is demarcated by expression of both the neuromodulator thyrotropin-releasing hormone (TRH) in the COApm and the TRH-receptor (TRHR) in the postsynaptic MEA glutamatergic neurons. Modulating TRH-expressing neurons as well as infusing TRHR ligand into the MEA phenocopy functional manipulation of the COApm-MEA circuit. We have, therefore, uncovered a novel neural mechanism that endows animals with the ability to modulate innate reproductive and aggressive social interactions according to the health and threat status of reciprocating individuals. Deficits in such a mechanism may lead to the spread of disease, while uncontrolled engagement may lead to pathological conditions, such as social withdrawal and depression.
Project description:Social behaviour is regulated by activity of host-associated microbiota across multiple species. However, the molecular mechanisms mediating this relationship remain elusive. We therefore determined the dynamic, stimulus-dependent transcriptional regulation of germ-free (GF) and GF mice colonised post weaning (exGF) in the amygdala, a brain region critically involved in regulating social interaction. In GF mice the dynamic response seen in controls was attenuated and replaced by a marked increase in expression of splicing factors and alternative exon usage in GF mice upon stimulation, which was even more pronounced in exGF mice. In conclusion, we demonstrate a molecular basis for how the host microbiome is crucial for a normal behavioural response during social interaction. Our data further suggest that social behaviour is correlated with the gene-expression response in the amygdala, established during neurodevelopment as a result of host-microbe interactions. Our findings may help toward understanding neurodevelopmental events leading to social behaviour dysregulation.
Project description:A substantial proportion of basal amygdala (BA) glutamate neurons project to nucleus accumbens (NAc). The evidence that these neurons are activated by reward and/or aversion is equivocal. Social stimuli are highly salient, and in male mice we conducted a detailed analysis of the responsiveness of BA-NAc neurons to estrous female (social reward, SR) or aggressive male (social aversion, SA). Both SR and SA activated c-Fos expression in a relatively high number of BA-NAc neurons in intermediate (int) BA. Using Fos-TRAP2 mice, the majority of social int-BA-NAc neurons were activated by either SR or SA, i.e. were monovalent, and in similar numbers. Fiber photometry provided corroborative evidence that int-BA-NAc neural pathway activity was similar in response to SR or SA. These findings contribute substantially to understanding the topography and valence-specificity of BA-NAc neurons with respect to highly salient stimuli, and to identifying molecular targets for treatment of reward- or aversion-specific psychopathologies.