Search PubMedSearch

SEARCH · Search PubMed

Results for “Contextual fear conditioning”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

3 recordsLinked to original sources

DYRK1A modulates fear memory formation via epigenetic modification.

Fear memory formation is crucial for survival, with the hippocampus playing a central role. This study investigates the behavioral and molecular aspects of fear memory formation, focusing on Dual-specificity tyrosine phosphorylation-regulated kinase 1 A (DYRK1A), a protein known to be critical for cognitive functions. Our results demonstrate that DYRK1A expression in hippocampal CA1 pyramidal neurons is downregulated after contextual fear conditioning (CFC). We also observed a decrease in DYRK1A binding to the Maoa promoter, suggesting its involvement in transcriptional regulation during fear memory formation. In subsequent experiments, we modulated DYRK1A expression using viral vectors. DYRK1A overexpression reduced freezing behavior, while knockdown enhanced it. At the molecular level, DYRK1A overexpression resulted in elevated H3K4me3 levels, while knockdown decreased it. These findings indicate that DYRK1A regulates fear memory formation via epigenetic modifications, altering H3K4me3 levels and influencing Maoa transcription in the hippocampus. This research highlights the nuclear role of DYRK1A and suggests its potential as a therapeutic target for neuropsychiatric disorders related to fear and memory.

Animals

Male and Female Mice Show Similar Fear Memory Performance Despite Hippocampal Immediate Early Gene Expression Differences During Encoding and Consolidation.

Accurate and efficient memory processing is essential for survival. A body of ongoing work in both human subjects and animal models suggests that memory processing may differ substantially between males and females. In mice, contextual fear memory (CFM) encoding, consolidation, and recall have been well studied, and the mouse hippocampus and amygdala have been implicated in these processes. The present pilot study addresses whether the activation of these brain regions differs substantially between male and female mice at each stage of CFM processing. We find that male and female mice show no differences in sleep behavior, which is essential for CFM consolidation, following single-trial contextual fear conditioning (CFC). We also find no significant differences in CFM recall performance between male and female mice. However, females show a trend for larger increases in CA1 cFos expression, relative to males, during CFM encoding. On the other hand, only males-but not females-show an apparent increase in cFos expression among dentate gyrus (DG) granule cells during CFM consolidation. Males also show a trend for a larger apparent reduction in cFos in CA1 and CA3 during CFM consolidation, relative to females. These preliminary findings highlight the idea that the neurobiological underpinnings of memory processing may differ between males and females, even when performance during recall is identical.

Animals

Role of conditioned contextual stimuli in reinstatement of extinguished fear.

If the unconditioned stimulus (US) is presented independently of the conditioned stimulus (CS) following extinction, the conditioned response may be reinstated to the CS. Three experiments are reported that suggest that reinstatement is mediated by conditioning to contextual stimuli that are present during both US presentation and testing. Shocks presented to rats following the extinction of conditioned suppression reliably reinstated suppression to the CS, but only when they were presented in the context in which testing was later to occur. Reinstatement was also reversed by extinguishing fear to the context through nonreinforced exposure to the context between shock presentation and testing. Reinstatement was obtained in these experiments in spite of procedures that have been used in the past to minimize the influence of context conditioning. Moreover, fear of the context was never detected directly by depressed bar-press rates in the absence of the CS. The results do not support the hypothesis that reinstatement results from an increment in the strength of a memory of the US that has been weakened during extinction. Problems inherent in controlling and detecting levels of context conditioning that may influence behavior toward nominal CSs are discussed.

Animals