TopicNeuroscience

fear memory

Explore Neuroscience Browse all domains

Content Overview

32Total items

29ePosters

3Seminars

Latest

SeminarNeuroscience

Circuit Mechanisms of Remote Memory

Lauren DeNardo, PhD

Department of Physiology, David Geffen School of Medicine, UCLA

Feb 11, 2025

Memories of emotionally-salient events are long-lasting, guiding behavior from minutes to years after learning. The prelimbic cortex (PL) is required for fear memory retrieval across time and is densely interconnected with many subcortical and cortical areas involved in recent and remote memory recall, including the temporal association area (TeA). While the behavioral expression of a memory may remain constant over time, the neural activity mediating memory-guided behavior is dynamic. In PL, different neurons underlie recent and remote memory retrieval and remote memory-encoding neurons have preferential functional connectivity with cortical association areas, including TeA. TeA plays a preferential role in remote compared to recent memory retrieval, yet how TeA circuits drive remote memory retrieval remains poorly understood. Here we used a combination of activity-dependent neuronal tagging, viral circuit mapping and miniscope imaging to investigate the role of the PL-TeA circuit in fear memory retrieval across time in mice. We show that PL memory ensembles recruit PL-TeA neurons across time, and that PL-TeA neurons have enhanced encoding of salient cues and behaviors at remote timepoints. This recruitment depends upon ongoing synaptic activity in the learning-activated PL ensemble. Our results reveal a novel circuit encoding remote memory and provide insight into the principles of memory circuit reorganization across time.

SeminarNeuroscience

Consolidation of remote contextual memory in the neocortical memory engram

Jun-Hyeong Cho

Oct 26, 2023

Recent studies identified memory engram neurons, a neuronal population that is recruited by initial learning and is reactivated during memory recall. Memory engram neurons are connected to one another through memory engram synapses in a distributed network of brain areas. Our central hypothesis is that an associative memory is encoded and consolidated by selective strengthening of engram synapses. We are testing this hypothesis, using a combination of engram cell labeling, optogenetic/chemogenetic, electrophysiological, and virus tracing approaches in rodent models of contextual fear conditioning. In this talk, I will discuss our findings on how synaptic plasticity in memory engram synapses contributes to the acquisition and consolidation of contextual fear memory in a distributed network of the amygdala, hippocampus, and neocortex.

SeminarNeuroscienceRecording

Drifting assemblies for persistent memory: Neuron transitions and unsupervised compensation

Raoul-Martin Memmesheimer

University of Bonn, Germany

Jun 29, 2022

Change is ubiquitous in living beings. In particular, the connectome and neural representations can change. Nevertheless behaviors and memories often persist over long times. In a standard model, associative memories are represented by assemblies of strongly interconnected neurons. For faithful storage these assemblies are assumed to consist of the same neurons over time. We propose a contrasting memory model with complete temporal remodeling of assemblies, based on experimentally observed changes of synapses and neural representations. The assemblies drift freely as noisy autonomous network activity or spontaneous synaptic turnover induce neuron exchange. The exchange can be described analytically by reduced, random walk models derived from spiking neural network dynamics or from first principles. The gradual exchange allows activity-dependent and homeostatic plasticity to conserve the representational structure and keep inputs, outputs and assemblies consistent. This leads to persistent memory. Our findings explain recent experimental results on temporal evolution of fear memory representations and suggest that memory systems need to be understood in their completeness as individual parts may constantly change.

fear memory

Latest

Circuit Mechanisms of Remote Memory

Consolidation of remote contextual memory in the neocortical memory engram

Drifting assemblies for persistent memory: Neuron transitions and unsupervised compensation

Mechanisms of contextual fear memory suppression and extinction by the Nucleus Reuniens-CA1 pathway

The activity of phosphodiesterase 4 in the dorsal hippocampus during reconsolidation sustains fear memory over time

Acute insulin administration enhances contextual fear memory independently of adrenaline, through increased hippocampus Bdnf expression

Brain-wide epigenetics mapping of fear memory engram cells

A fear memory engram in the mouse auditory cortex

A midbrain-extended amygdala pathway controls contextual fear memory and predator odor avoidance

Neuropeptidergic modulation of cortical circuits for fear memory

Role of hippocampo-prefrontal circuits in fear memory consolidation

The Temporal Study of Traumatic Stress Related Fear Memory Retrieval in a Rat Model of Post-Traumatic Stress Disorder: Brain Wave and Transcriptome-Level Gene Profiling

Astrocytic Foxo1 regulates hippocampal spinogenesis and synaptic plasticity and enhances fear memory

Basolateral amygdala activity phase-locked to neocortical slow waves underlies fear memory consolidation

Encoding and retrieval of a contextual fear memory evoke divergent expression of immediate-early genes Arc and c-Fos

Engram-specific synaptic potentiation is important for fear memory formation and expression in vivo

Exploring sex hormones and menstrual cycle influence on fear memory through a multidimensional approach

Fear memory recall via hippocampal somatostatin interneurons

Fear memory under acute phase shift: Potential modulation of prefrontal-hippocampal circuit by orexin

A midbrain-extended amygdala pathway controls contextual fear memory

Molecular mechanisms of remote fear memory extinction

A multiple Arc tagging system to investigate the effect of psilocybin on fear memory extinction

Neuronal determinants of contextual fear memory generalization: From normal to pathological fear

Neuronal pERK expression in amygdala subregions reveals differential encoding of fear memory strength in a mouse model of PTSD

Neuronal types in the mouse amygdala and their transcriptional states in fear memory

Nogo-A regulates fear memory processes and memory engram formation by modulating neuronal excitability in a sex-specific manner

Pattern completion of contextual fear memory: Modulation by hippocampal somatostatin-positive interneurons

Potential role for microRNA regulation in the tuning of engram recruitment during fear memory consolidation

D1 receptors in the nucleus accumbens regulate social fear memory processing

Sex-specific effects in fear memory generalization in IL-6 knockout mice

Strong sexual dimorphism in the evolution of fear memory revealed by brain-wide activation analysis

Temporal dynamics of neuronal excitability in the lateral amygdala mediates allocation to an engram supporting conditioned fear memory