Engram neurons: Encoding, consolidation, retrieval, and forgetting of memory

Molecular Psychiatry, Journal Year: 2023, Volume and Issue: 28(8), P. 3207 - 3219

Published: June 27, 2023

Tremendous strides have been made in our understanding of the neurobiological substrates memory - so-called "engram". Here, we integrate recent progress engram field to illustrate how neurons transform across "lifespan" a from initial encoding, consolidation and retrieval, ultimately forgetting. To do so, first describe cell-intrinsic properties shape emergence at encoding. Second, highlight these encoding preferentially participate synaptic- systems-level memory. Third, changes during guide neural reactivation facilitate recall. Fourth, mechanisms forgetting, can counteract established consolidation, retrieval. Motivated by experimental results four sections, conclude proposing some conceptual extensions traditional view engram, including broadening cell-type participation within engrams stages. In collection, review synthesizes general principles stages, describes future avenues further understand dynamic engram.

Language: Английский

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The times they are a-changin’: a proposal on how brain flexibility goes beyond the obvious to include the concepts of “upward” and “downward” to neuroplasticity

Molecular Psychiatry, Journal Year: 2022, Volume and Issue: 28(3), P. 977 - 992

Published: Dec. 27, 2022

Abstract Since the brain was found to be somehow flexible, plastic, researchers worldwide have been trying comprehend its fundamentals better understand itself, make predictions, disentangle neurobiology of diseases, and finally propose up-to-date treatments. Neuroplasticity is simple as a concept, but extremely complex when it comes mechanisms. This review aims bring light an aspect about neuroplasticity that often not given enough attention should, fact brain’s ability change would include disconnect synapses. So, neuronal shrinkage, decrease in spine density or dendritic complexity should included within concept part mechanisms, impairment it. To end, we extensively describe variety studies involving topics such neurodevelopment, aging, stress, memory homeostatic plasticity highlight how weakening disconnection synapses organically permeate so many ways good practice intrinsic physiology. Therefore, break down into two sub-concepts, “upward neuroplasticity” for changes related synaptic construction “downward deconstruction. With these could understood from bigger landscape vector which both directions taken flexibly adapt certain demands. Such paradigm shift allow understanding avoid any data interpretation bias, once makes clear there no morality with regard organic physiological involve dynamic biological systems seen brain.

Language: Английский

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Cortico-subcortical networks that determine behavioral memory renewal are redefined by noradrenergic neuromodulation

Scientific Reports, Journal Year: 2025, Volume and Issue: 15(1)

Published: March 20, 2025

Abstract During spatial appetitive extinction learning (EL), rodents learn that previously rewarded behavior is no longer rewarded. Renewal of the extinguished enabled by re-exposure to context in which occurred. When renewal response (RR) unrewarded, it rapidly followed (RE). Although hippocampus known be engaged, whether this dynamic supported different brain networks unclear. To clarify this, male rats engaged context-dependent memory acquisition, EL and RR testing a T-Maze. Fluorescence situ hybridization disambiguated somatic immediate early gene expression neuronal somata or RE. Graph analysis revealed pronounced hippocampal connectivity with retrosplenial prefrontal cortex (PFC) during initial RR. By contrast, RE was accompanied shift towards elevated coordinated activity within all subfields. Given β-adrenergic receptors (β-AR) regulate memory, we activated β-AR further scrutinize these network effects. This enhanced prevented Effects were associated initially increased thalamic-hippocampus activity, decrease intraconnectivity predominance PFC. Our findings highlight critical hippocampal-cortical-thalamic underpins behavior, noradrenergic neuromodulation playing pivotal role governing circuit’s dynamics.

Language: Английский

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Distinct engrams control fear and extinction memory

Hippocampus, Journal Year: 2024, Volume and Issue: 34(5), P. 230 - 240

Published: Feb. 23, 2024

Abstract Memories are stored in engram cells, which necessary and sufficient for memory recall. Recalling a might undergo reconsolidation or extinction. It has been suggested that the original is reactivated during so can be updated. Conversely, extinction training, new formed suppresses engram. Nonetheless, it unknown whether creates modifies fear In this study, we utilized Daun02 procedure, uses c‐Fos‐lacZ rats to induce apoptosis of strongly activated neurons examine trace emerges as result short long reactivation, if these processes rely on modifications within located basolateral amygdala (BLA) infralimbic (IL) cortex. By eliminating consolidation observed significant impacts memory, highlighting importance BLA processes. Although were unable show any impact when removing after test previously extinguished BLA, disrupting IL aversive was suppressed by memory. Thus, demonstrated cortex plays crucial role network involved extinction, specific node alone impair behavior. Additionally, our findings indicate memories formation supporting theory whereas process reactivates same trace.

Language: Английский

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Network-level changes in the brain underlie fear memory strength

eLife, Journal Year: 2023, Volume and Issue: 12

Published: Dec. 4, 2023

The strength of a fear memory significantly influences whether it drives adaptive or maladaptive behavior in the future. Yet, how mild and strong memories differ underlying biology is not well understood. We hypothesized that this distinction may be exclusively result changes within specific brain regions, but rather outcome collective connectivity across multiple regions neural network. To test this, rats were conditioned protocols varying intensities to generate memories. Neuronal activation driven by recall was measured using c-fos immunohistochemistry 12 implicated learning memory. interregional coordinated activity computed graph-based functional networks generated compare at systems level. Our results show supported well-connected network with small-world properties which amygdala well-positioned modulated other regions. In contrast, disrupted isolated from These findings indicate differ, implications for understanding treating disorders dysregulation.

Language: Английский

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Evaluating the effects of single, multiple, and delayed systemic rapamycin injections to contextual fear reconsolidation: Implications for the neurobiology of memory and the treatment of PTSD-like re-experiencing

Behavioural Brain Research, Journal Year: 2024, Volume and Issue: 461, P. 114855 - 114855

Published: Jan. 5, 2024

The mechanistic target of rapamycin (mTOR) kinase is known to mediate the formation and persistence aversive memories. Rapamycin, an mTOR inhibitor, administered around time reactivation blocks retrieval-induced activity de novo protein synthesis in brains rodents, while correspondingly diminishing subsequent fear memory. goal current experiments was further explore rapamycin's effects on memory persistence. First, we examined whether blockade at different time-points after attenuates contextual We show that treatment 3 or 12 h post-reactivation disrupts Second, consecutive days paired with had additive over a single pairing disrupting additional reactivation-rapamycin pairings exacerbates reconsolidation impairment. Finally, if impaired from any after-effects learning recalling new association. rapamycin-impaired does not affect recall protects against generalization. Our findings improve our understanding mTOR- dependent processes, as well provide insight into potentially novel options for stress-related psychopathologies such posttraumatic stress disorder.

Language: Английский

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Rape Victims’ Perceptions of Quality of Encounters With the Swedish Police

Violence Against Women, Journal Year: 2024, Volume and Issue: unknown

Published: April 7, 2024

This study focused on raped women's perceptions of their encounters with Swedish police, a specific focus quality encounters, trust, questions asked during police interviews, and justice. One hundred six rape victims, 74 whom had reported to the answered web-based questionnaire. Results show that where officers explained line questioning perceived intrusiveness was lower, as level victim-blaming. Higher were associated higher trust in legal system work, levels received Findings highlight importance trauma-informed policing response sexual assault provide insights which might help inform policy practice developments, both Sweden more generally.

Language: Английский

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Appraising reconsolidation theory and its empirical validation

Psychonomic Bulletin & Review, Journal Year: 2022, Volume and Issue: 30(2), P. 450 - 463

Published: Sept. 9, 2022

Language: Английский

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Network-level changes in the brain underlie fear memory strength

eLife, Journal Year: 2023, Volume and Issue: 12

Published: June 27, 2023

The strength of a fear memory significantly influences whether it drives adaptive or maladaptive behavior in the future. Yet, how mild and strong memories differ underlying biology is not well understood. We hypothesized that this distinction may be exclusively result changes within specific brain regions, but rather outcome collective connectivity across multiple regions neural network. To test this, rats were conditioned protocols varying intensities to generate memories. Neuronal activation driven by recall was measured using c-fos immunohistochemistry 12 implicated learning memory. interregional coordinated activity computed graph-based functional networks generated compare at systems level. Our results show supported well-connected network with small-world properties which amygdala well-positioned modulated other regions. In contrast, disrupted isolated from These findings indicate differ, implications for understanding treating disorders dysregulation.

Language: Английский

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Lack of Effect of Propranolol on the Reconsolidation of Conditioned Fear Memory due to a Failure to Engage Memory Destabilisation

Neuroscience, Journal Year: 2021, Volume and Issue: 480, P. 9 - 18

Published: Nov. 10, 2021

Language: Английский

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