<p class="reg-normal">Researchers at the University of California, Davis, have made significant strides in understanding the amygdala, a brain region crucial for emotional processing, particularly fear and anxiety. Their study, published in the *American Journal of Psychiatry* on October 30, highlights new clusters of cells with distinct gene expression patterns in the amygdala of humans and non-human primates, paving the way for more targeted treatments for anxiety and related disorders that affect millions.&nbsp;</p><p class="reg-normal">Drew Fox, associate professor in the UC Davis Department of Psychology, emphasized the amygdala's central role in emotion but pointed out that its overall size and structure are not reliable predictors of emotional disorders. Previous research in rodents revealed that different cell types within the amygdala's subregions have unique and sometimes opposing functions, suggesting that specific alterations in these cell types could contribute to the emergence of disorders like anxiety and depression.&nbsp;</p><p class="reg-normal">Graduate student Shawn Kamboj led a collaboration to identify these cell types in both human and rhesus macaque amygdalae by analyzing gene expression patterns. By employing single-cell RNA sequencing, the team isolated individual cells from brain samples and sequenced their RNA, revealing active genes and allowing for the classification of cells based on their gene expression.&nbsp;</p><p class="reg-normal">One significant finding was the identification of cells expressing the FOXP2 gene, located in the intercalated cells at the edges of the amygdala. In rodent models, these cells are known as “gatekeepers” that regulate the flow of signals in and out of the amygdala, making them a promising target for developing new treatments.&nbsp;</p><p class="reg-normal">The study also uncovered both similarities and differences in cell types between humans and non-human primates, enhancing our understanding of how animal models can inform human psychiatric disorders. Notably, FOXP2-expressing cells also exhibited anxiety-related gene expression and contained a receptor, Neuropeptide FF Receptor 2 (NPFFR2), which is a potential drug target. This discovery could guide the development of new treatment strategies by suggesting drugs that activate the NPFFR2 pathway for addressing anxiety-related disorders.&nbsp;</p><p class="reg-normal">As anxiety disorders can manifest in various forms, identifying the specific cell types involved may allow researchers to pinpoint critical “chokepoints” that affect many individuals suffering from debilitating anxiety. Fox stated, “If we're developing a drug to target the amygdala, we want to know which cell type we are targeting.” This research lays the foundation for more effective interventions and a deeper understanding of the biological underpinnings of anxiety and related conditions.</p>