Project description:These data are from the brains (amygdala and hippocampus) of mice originally derived from a cross between C57BL/6J and DBA/2J inbred strains. We used short-term selection to produce outbred mouse lines with differences in contextual fear conditioning, which is a measure of fear learning. We selected for a total of 4 generations. Fear learning differed in the selected lines and this difference was stronger with each successive generation of selection. These mice also showed differences for measures of anxiety-like behavior, but were not different for tests of non-fear motivated learning, suggesting that selection altered alleles that are specifically involved in emotional behaviors. We identified several QTLs for the selection response. We used Affymetrix microarrays to identify differentially expressed genes in the amygdala and hippocampus of mice from the final generation of selection. Amygdala and hippocampus samples were rapidly dissected out of experimentally naïve mice f rom each selected line. Three samples were pooled and hybridized to each array. Experimentally naïve mice were used because the behavior of the mice can be reliably anticipated due to their lineage. Thus, these gene expression differences are not due to the response to human handling, foot shock or fear-inducing conditioned stimuli. We have a second similar study that focuses on a different selected population that was based on C57BL/6J and A/J mice (see GES4034).
Project description:This dataset constitutes the first Sono-Seq study of chromatin accessibility following contextual fear conditioning in the mouse hippocampus.
Project description:This dataset constitutes the first RNA-seq study of gene expression following contextual fear conditioning in the mouse hippocampus.
Project description:Extinction learning refers to the phenomenon that a previously learned response to an environmental stimulus, for example the expression of an aversive behavior upon exposure to a specific context, is reduced when the stimulus is repeatedly presented in the absence of a previously paired aversive event. Extinction of fear memories has been implicated with the treatment of anxiety disease but the molecular processes that underlie fear extinctionare only beginning to emerge. Here we show that fear extinction initiates up-regulation of hippocampal insulin-growth factor 2 (Igf2) and down-regulation of insulin-growth factor binding protein 7 (Igfbp7). In line with this observation we demonstrate that IGF2 facilitates fear extinction, while IGFBP7 impairs fear extinction in an IGF2-dependent manner. Furthermore, we identify one cellular substrate of altered IGF2-signaling during fear extinction. To this end we show that fear extinction-induced IGF2/IGFBP7-signaling promotes the survival of 17-19 day-old newborn hippocampal neurons. In conclusion, our data suggests that therapeutic strategies that enhance IGF2-signaling and adult neurogenesis might be suitable to treat disease linked to excessive fear memory. We employed mice to investigate fear extinction in the hippocampus-dependent contextual fear conditioning paradigm. To this end, male C57BL/6J mice were exposed to the fear conditioning box (context) followed by an electric foot-shock which elicits the acquisition of conditioned contextual fear. For extinction training animals were repeatedly reexposed to the conditioned context on consecutive days (24h interval) without receiving the footshockagain (extinction trial, E). This procedure eventually results in the decline of the aversive freezing behavior. Mice that were exposed to the conditioning context without receiving fear conditioning training served as control groups. To gain a better understanding of the molecular processes underlying fear extinction we performed a genome-wide analysis of the hippocampal transcriptome during fear extinction. In the employed paradigm fear extinction is a gradual process. To capture the longitudinal course of fear extinction we decided to perform hippocampal microarray analysis at two time points: (1) After the first extinction trial (E1) when animals display high levels of aversive freezing behavior and (2) at the extinction trial on which the freezing behavior was significantly reduced when compared to E1. This extinction trial, in the case of this experiment E5, we termed “extinction trial low freezing” (ELF). Mice that were exposed to the conditioning context without receiving fear conditioning training served as control groups (3). For all three groups we hybridized 5 samples (biological replicates).
Project description:Using Illumina MouseWG-6v2 microarrays, we investigated the gene transcription changes in microglia and peripheral monocytes after contextual fear conditioning of C57BL/6J mice. Mice were trained with or without a single minimized footshock stimulation (0-s or 2-s, 0.4 mA) and re-exposed to the training context without footshock for three different durations 24 h later: 0 min (FS0), 3 min (FS3), or 30 min (FS30). Whole brain microglia and peripheral monocytes were prepared 24 h after re-exposure using a neural tissue dissociation kit, including non-footshock controls for two re-exposure durations (Con3 and Con30). The data can be valuable for researchers interested in glial cells and neurotransmission studies and are related to the research article “Contextual fear conditioning regulates synapse-related gene transcription in mouse microglia”.
Project description:Investigating the molecular basis and correlates of anxiety-related and depression-like behaviors, we generated a mouse model consisting of high (HAB), normal (NAB) and low (LAB) anxiety-related behavior mice. We utilized the elevated plus-maze for testing the genetic predisposition to anxiety-related behavior and, consequently, used this as selection criterion for the inbreeding of our animals. In depression-related tests, HAB mice display a more passive, depression-like coping strategy than LAB mice, resembling clinical comorbidity of anxiety and depression as observed in psychiatric patients. Using a microarray approach, the hypothalamic paraventricular nucleus (PVN), the basolateral (BLA) and central amygdala (CeA), the cingulate cortex (Cg) and the dentate gyrus (DG) – centers of the central nervous anxiety and fear circuitries – were investigated and screened for differences between HAB, NAB and LAB mice. Analysis was performed from four to six animals per line (HAB, NAB and LAB from generation 25, respectively) per brain region, giving a total of 78 individual arrays analyzed. The LAB mouse line is referred to as reference.