Single cell RNAseq of brian cells in the basolateral amygdala with fear conditioning
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ABSTRACT: Memory encodes past experiences, thereby enabling future plans. The basolateral amygdala (BLA) is a center of salience networks that underlie emotional experiences and thus plays a key role in long-term fear memory formation. Here we used single-cell transcriptomics to illuminate the cellular and molecular architecture of the role of the basolateral amygdala in long-term memory. We identified transcriptional signatures in subpopulations of neurons and astrocytes that were memory-specific and persisted for weeks. These transcriptional signatures implicate neuropeptide and brain-derived neurotrophic factor (BDNF) signaling, mitogen-activated protein kinase (MAPK) and cAMP response element-binding protein (CREB) activation, ubiquitination pathways, and synaptic connectivity as key components of long-term memory. Strikingly, upon long-term memory formation a neuronal sub-population defined by increased Penk and decreased Tac expression constituted the most prominent component of the BLA’s memory engram.
Project description:Fear conditioning in rats leads to long term memory (LTM) formation. A central neural substrate for LTM is the basolateral amygdala. We sought the expression changes specific to LTM at 6h following anesthesia with isoflurane (a general anesthetic and an effective amnestic agent), following pain (a component of conditioning), and following conditioning in presence and absence of isoflurane. Keywords = anesthesia, amygdala, LTM, Rampil, Isoflurane, fear, memory Keywords: other
Project description:Sparse populations of neurons in the dentate gyrus (DG) of the hippocampus are causally implicated in the encoding of contextual fear memories. However, engram-specific molecular mechanisms underlying memory consolidation remain largely unknown. Here we perform unbiased RNA sequencing of DG engram neurons 24h after contextual fear conditioning to identify transcriptome changes specific to memory consolidation. DG engram neurons exhibit a highly distinct pattern of gene expression, in which CREB-dependent transcription features prominently (P=6.2x10-13), including Atf3 (P=2.4x10-41), Penk (P=1.3x10-15), and Kcnq3 (P=3.1x10-12). Moreover, we validate the functional relevance of the RNAseq findings by establishing the causal requirement of intact CREB function specifically within the DG engram during memory consolidation, and identify a novel group of CREB target genes involved in the encoding of long-term memory.
Project description:Fear conditioning in rats leads to long term memory (LTM) formation. A central neural substrate for LTM is the basolateral amygdala. We sought the expression changes specific to LTM at 6h following anesthesia with isoflurane (a general anesthetic and an effective amnestic agent), following pain (a component of conditioning), and following conditioning in presence and absence of isoflurane.
Project description:Basolateral excitatory neurons constitute a prominent output neuron class of the amygdala. Here, we examined diversity in this cell type using single-cell RNA-seq.
Project description:Alcohol affects gene expression in several brain regions. The amygdala is a key structure in the brainâs emotional system and in recent years the crucial importance of the amygdala in drug-seeking and relapse has been increasingly recognized. In this study gene expression screening was used to identify genes involved in alcoholism in the human basolateral amygdala. The results show that alcoholism affects a broad range of genes and many systems including genes involved in synaptic transmission, neurotransmitter transport, structural plasticity, metabolism, energy production, transcription and RNA processing and the circadian cycle. In particular, genes involved in the glutamate system were affected in the alcoholic patients. In the amygdala the glutamate system is involved in the acquisition, consolidation, expression and extinction of associative learning, which is a vital part of addiction, and in alcohol abusers it is associated with withdrawal anxiety and neurodegeneration. Downregulation of the excitatory amino acid transporters GLAST, GLT-1 and the AMPA glutamate receptor 2 (GluR2) revealed by the microarray were confirmed by Western blots. The decreased expression of GLAST, GLT-1 and GluR2 in the alcoholic patients may increase glutamate tone and activity in the basolateral amygdala and this may contribute to neurodegeneration as well as the expression of associative memories and anxiety which underlie continued drug-seeking and chronic relapse. Two-condition experiment, alcoholics vs controls. Biological replicates: 6 alcoholics 6 controls, one replicate per array.
Project description:Activity-dependent transcriptional profiling was performed in the basolateral amygdala in order to identify unique genetic markers for functionally distinct neuronal populations
Project description:Alcohol affects gene expression in several brain regions. The amygdala is a key structure in the brain’s emotional system and in recent years the crucial importance of the amygdala in drug-seeking and relapse has been increasingly recognized. In this study gene expression screening was used to identify genes involved in alcoholism in the human basolateral amygdala. The results show that alcoholism affects a broad range of genes and many systems including genes involved in synaptic transmission, neurotransmitter transport, structural plasticity, metabolism, energy production, transcription and RNA processing and the circadian cycle. In particular, genes involved in the glutamate system were affected in the alcoholic patients. In the amygdala the glutamate system is involved in the acquisition, consolidation, expression and extinction of associative learning, which is a vital part of addiction, and in alcohol abusers it is associated with withdrawal anxiety and neurodegeneration. Downregulation of the excitatory amino acid transporters GLAST, GLT-1 and the AMPA glutamate receptor 2 (GluR2) revealed by the microarray were confirmed by Western blots. The decreased expression of GLAST, GLT-1 and GluR2 in the alcoholic patients may increase glutamate tone and activity in the basolateral amygdala and this may contribute to neurodegeneration as well as the expression of associative memories and anxiety which underlie continued drug-seeking and chronic relapse.
Project description:KLB-Cre mice were crossed to Ai14 mice to label KLB-expressing cells with tdTomato. The basolateral amygdala was then dissected out and tdTomato positive cells were isolated using FACs sorting. FACs sorted cells were then captured for single cell RNA sequencing analysis using the BD Rhapsody Whole Transcriptome Analysis kit.