Project description:Inhibitory neurons are the predominant type of neuron in the mouse central amygdala. Here, we examined diversity in this cell type using single-cell RNA-seq.
Project description:TRAP translational profiling is a method that allows investigators to genetically characterize specific cell types in complex tissues such as mouse brain. Using this technique we obtained RNA-Seq data from actively translating transcripts present in neurons in the cortex-amygdala transition zone (CxA) of adult Lypd1-EGFP/Rpl10a (OI82) mice. This work was supported by a grant from the National Institute on Drug Abuse P30DA035756 to N.H.
Project description:Both the amygdala and the bed nucleus of the stria terminalis (BNST) have been implicated in maladaptive anxiety characteristic of anxiety disorders. However, the underlying circuit and cellular mechanisms have remained elusive. Here we show that mice with Erbb4 gene deficiency in somatostatin-expressing (SOM+) neurons exhibit heightened anxiety as measured in the elevated plus maze test and the open field test, two assays commonly used to assess anxiety-related behaviors in rodents. Using a combination of electrophysiological, molecular, genetic and pharmacological techniques we demonstrate that the abnormal anxiety in the mutant mice is caused by enhanced excitatory synaptic inputs onto SOM+ neurons in the central amygdala (CeA), and the resulting reduction in inhibition onto downstream SOM+ neurons in the BNST. Notably, our results indicate that an increase in dynorphin signaling in SOM+ CeA neurons mediates the paradoxical reduction in inhibition onto SOM+ BNST neurons, and that the consequent enhanced activity of SOM+ BNST neurons is both necessary for and sufficient to drive the elevated anxiety. Finally, we show that the elevated anxiety and the associated synaptic dysfunctions and increased dynorphin signaling in the CeA-BNST circuit of the Erbb4 mutant mice can be recapitulated by stress in wild-type mice. Together, our results unravel previously unknown circuit and cellular processes in the central extended amygdala that can cause maladaptive anxiety.
Project description:The suppression of fear memory in the absence of danger (fear extinction) requires coordinated neural activity within the amygdala and medial prefrontal (prelimbic and infralimbic) cortex. Any behavior has a transcriptomic signature that is modified by environmental experiences, and specific genes are involved in functional plasticity and synaptic wiring during fear memory and extinction. In the present study, we investigated the effects of optogenetic manipulations of prelimbic pyramidal neurons on amygdala gene expression to analyze the specific transcriptional pathways involved in fear extinction. To this aim, transgenic mice (Thy1-COP4) having cortical and amygdala pyramidal neurons optogenetically excitable were (or not) fear-conditioned. During the extinction phase, the mice received optogenetic (or sham) stimulations to maintain the activation of the prelimbic pyramidal neurons and impair fear extinction. At the end of behavioral testing, electrophysiological (Excitatory Post-Synaptic Currents) and morphological (spinogenesis) correlates were evaluated in the pyramidal neurons of prelimbic cortex. Furthermore, transcriptomic cell-specific RNA-analyses (differential gene expression profiling and functional enrichment analyses) were performed in amygdala pyramidal neurons. Results demonstrate that pyramidal neurons of prelimbic cortex are involved in modulation of the fear responses during extinction phase and their optogenetic stimulation in fear-conditioned mice results in strong modifications of the amygdala transcriptome. Understanding the transcriptomic architecture of fear extinction may facilitate the comprehension of fear-related disorders.
Project description:The central amygdala (CEA) is a brain region that consists of primarily GABAergic neurons. It has been widely investigated for its role in many innate and adaptive behaviors, such as appetitive and defensive behaviors. Despite the complex functions of CEA, the molecular diversity of CEA neurons has not been systemically examined. Here, we performed single-cell RNA-sequencing (scRNA-Seq) in the CEA to classify the molecularly defined neuron types in this region.
Project description:Pianp (also known as Leda-1) is a type I transmembrane protein with preferential expression in the mammalian central nervous system. We used microarrays to analyze the programme of gene expression in murine brain regions amygdala, cortex, hippocampus and hypothalamus of Pianp deficient mice.