scholarly journals Effects of intra-hippocampal corticosterone and sleep on consolidation of complex memory of aversive experience in rats

2021 ◽  
Author(s):  
Alena Brukhnová ◽  
Ewa Szczurowska ◽  
Čestmír Vejmola ◽  
Rachel R. Horsley ◽  
Eduard Kelemen
Keyword(s):  
Fear Conditioning ◽  
Memory Consolidation ◽  
Traumatic Event ◽  
Corticosterone Level ◽  
Stressful Event ◽  
List Type ◽  
Fear Response ◽  
Sleep State ◽  
Auditory Cue ◽  
Wake State

AbstractFormation and consolidation of memories for highly stressful (traumatic) events is a complex process that involves interplay between multiple memory systems and has implications for etiology and treatment of stress- and trauma-related disorders. Here we study effects of sleep/wake state and high intra-hippocampal corticosterone on consolidation of aversive contextual memories as well as consolidation of association between simple trauma-related cues and fear response in rats. Animals were implanted with EEG and EMG electrodes for sleep assessment and cannulas for intra-hippocampal corticosterone application. They were familiarized to a “safe box” and then trained in fear conditioning paradigm in a distinct “shock box” with a prominent simple auditory cue serving as a phasic background cue. Immediately after conditioning, animals received bilateral intra-hippocampal saline (1μl) or corticosterone (10ng in 1μl saline) injection and were either allowed to sleep or were kept awake for a following two-hour consolidation period. Memory test twenty-four hours later revealed that the saline-injected animals with sleep during consolidation had significantly stronger freezing response in the shock box compared to the safe box as well as increased freezing in response to the tone. Lack of post-learning sleep in saline injected animals led to generalization of fear response to the safe context, while association between simple cue and fear response was preserved. High intra-hippocampal corticosterone level during memory consolidation led to generalization of fear response to the safe context, regardless of sleep/wake state, while enhancement of response to single stimulus was not observed. Our results show how manipulation of conditions during consolidation can lead to greatly variable complex memories for a traumatic episode and distinct behavioral outcomes.HighlightsWe studied effect of sleep and intrahippocampal corticosterone on consolidation of memories surrounding stressful event modeled by fear conditioning in rats.Sleep following traumatic fear conditioning event is important for subsequent manifestation of fear response (freezing) specifically in the context of traumatic event but not in a neutral safe context.Lack of sleep or high intra-hippocampal corticosterone level during memory consolidation leads to generalization of fear response to both the traumatic and safe context.Increased freezing in response to a trauma-related auditory cue was observed in saline injected rats regardless of wake/sleep state during consolidation.Post-learning intra-hippocampal corticosterone injection blocked response to a trauma-related auditory cue regardless of wake/sleep state during consolidation.

scholarly journals The Posterior Insular Cortex is Necessary for the Consolidation of Tone Fear Conditioning

2020 ◽  
Author(s):  
J.P.Q. de Paiva ◽  
A.P.A. Bueno ◽  
M. Dos Santos Corrêa ◽  
M.G.M. Oliveira ◽  
T.L Ferreira ◽  
...  
Keyword(s):  
Fear Conditioning ◽  
Cognitive Processing ◽  
Memory Consolidation ◽  
Conditioned Fear ◽  
Conditioning Session ◽  
Insular Cortex ◽  
Fear Memory ◽  
Contextual Fear Conditioning ◽  
List Type ◽  
Functional Inactivation

ABSTRACTThe insular cortex (IC) is notably implicated in emotional and cognitive processing; however, little is known regarding to what extent its two main subregions play functionally distinct roles on memory consolidation of conditioned fear tasks. Here we verified the effects of temporary functional inactivation of the anterior (aIC) and posterior IC (pIC) on contextual and tone fear memory. Rats received post-training bilateral infusions of the GABAA receptor agonist muscimol into either the aIC or pIC and were tested 48 and 72 hours after the conditioning session to assess contextual (CFC) and tone (TFC) fear conditioning, respectively. Inactivation of the aIC during memory consolidation did not affect fear memory for CFC or TFC. On the other hand, post-training inactivation of the pIC impaired TFC but not CFC. Our findings indicate that the pIC is a necessary part of the neural circuitry related to the consolidation of cued-fear memories.HighlightsWe studied the role of the anterior (aIC) and posterior (pIC) insula in fear memoryPost-training inactivation of aIC and pIC did not impact contextual fear conditioningThe pIC but not aIC is necessary for the consolidation of tone fear conditioning

scholarly journals Hippocampal corticosterone impairs memory consolidation during sleep but improves consolidation in the wake state

Hippocampus ◽  
2014 ◽  
Vol 24 (5) ◽  
pp. 510-515 ◽  
Author(s):  
Eduard Kelemen ◽  
Marie Bahrendt ◽  
Jan Born ◽  
Marion Inostroza
Keyword(s):  
Memory Consolidation ◽  
Wake State

scholarly journals Memory Consolidation for Contextual and Auditory Fear Conditioning Is Dependent on Protein Synthesis, PKA, and MAP Kinase

1999 ◽  
Vol 6 (2) ◽  
pp. 97-110 ◽  
Author(s):  
Glenn E. Schafe ◽  
Nicole V. Nadel ◽  
Gregory M. Sullivan ◽  
Alexander Harris ◽  
Joseph E. LeDoux
Keyword(s):  
Protein Synthesis ◽  
Map Kinase ◽  
Fear Conditioning ◽  
Memory Consolidation ◽  
Molecular Mechanisms ◽  
Short Term Memory ◽  
Long Term Potentiation ◽  
Fear Memory ◽  
Term Memory

Fear conditioning has received extensive experimental attention. However, little is known about the molecular mechanisms that underlie fear memory consolidation. Previous studies have shown that long-term potentiation (LTP) exists in pathways known to be relevant to fear conditioning and that fear conditioning modifies neural processing in these pathways in a manner similar to LTP induction. The present experiments examined whether inhibition of protein synthesis, PKA, and MAP kinase activity, treatments that block LTP, also interfere with the consolidation of fear conditioning. Rats were injected intraventricularly with Anisomycin (100 or 300 μg), Rp-cAMPS (90 or 180 μg), or PD098059 (1 or 3 μg) prior to conditioning and assessed for retention of contextual and auditory fear memory both within an hour and 24 hr later. Results indicated that injection of these compounds selectively interfered with long-term memory for contextual and auditory fear, while leaving short-term memory intact. Additional control groups indicated that this effect was likely due to impaired memory consolidation rather than to nonspecific effects of the drugs on fear expression. Results suggest that fear conditioning and LTP may share common molecular mechanisms.

The Influence of Event and Reaction Context on Clinicians’ Disorder Diagnoses

2017 ◽  
Vol 6 (2) ◽  
pp. 203-215 ◽  
Author(s):  
Erienne R. Weine ◽  
Nancy S. Kim
Keyword(s):  
Life Events ◽  
Stress Disorder ◽  
Traumatic Event ◽  
Behavioral Symptoms ◽  
Stressful Event ◽  
Major Depressive ◽  
Future Directions ◽  
Vignette Study ◽  
Reaction Severity

Clinicians’ judgments about clients can be influenced by the causal context (e.g., life events) preceding behavioral symptoms. However, it is unclear whether this influence extends to diagnosis judgments. In diagnosing Posttraumatic Stress Disorder (PTSD), traumatic event context must be present, and severe immediate reaction context was formerly required for many years. In a vignette study, we systematically examined whether event and reaction severity influence clinicians’ open-ended diagnoses of PTSD behaviors, Major Depressive Disorder (MDD) behaviors, and nondisordered behaviors. Clinicians made more diagnoses of PTSD for all three types of behaviors (PTSD, MDD, distressed) given a traumatic event than a mildly stressful event but simultaneously found the behaviors to be less abnormal. We found no evidence that reaction context influenced diagnoses. Future directions and the role of causal context in clinical diagnosis are discussed.

scholarly journals Propofol Enhances Memory Formation via  an Interaction with the Endocannabinoid System

2011 ◽  
Vol 114 (6) ◽  
pp. 1380-1388 ◽  
Author(s):  
Daniela Hauer ◽  
Patrizia Ratano ◽  
Maria Morena ◽  
Sergio Scaccianoce ◽  
Isabel Briegel ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Acid Amide ◽  
Avoidance Performance ◽  
Endocannabinoid System ◽  
Inhibitory Avoidance ◽  
Dark Compartment ◽  
Vehicle Group ◽  
Stressful Event ◽  
Avoidance Task ◽  
General Anesthetics

Background Propofol is associated with postoperative mood alterations and induces a higher incidence of dreaming compared with other general anesthetics. These effects might be mediated by propofol's inhibitory action on fatty acid amide hydrolase, the enzyme that degrades the endocannabinoid anandamide. Because propofol is also associated with a higher incidence of traumatic memories from perioperative awareness and intensive care unit treatment and the endocannabinoid system is involved in regulating memory consolidation of emotional experiences, the authors investigated whether propofol, at anesthetic doses, modulates memory consolidation via an activation of the endocannabinoid system. Methods Male Sprague-Dawley rats were trained on an inhibitory avoidance task in which they received an inescapable foot shock upon entering the dark compartment of the apparatus. Drugs were administered intraperitoneally immediately or 30, 90, or 180 min after training. On the retention test 48 h later, the latency to reenter the dark compartment was recorded and taken as a measure of memory retention. Results The anesthetic doses of propofol administered after training significantly increased latencies of 48-h inhibitory avoidance performance (483.4 ± 181.3, 432.89 ± 214.06, 300 and 350 mg/kg, respectively; mean ± SD) compared with the corresponding vehicle group (325.33 ± 221.22, mean ± SD), which is indicative of stronger memory consolidation in propofol treated rats. Administration of a nonimpairing dose of the cannabinoid receptor antagonist rimonabant blocked the memory enhancement induced by propofol (123.39 ± 133.10, mean ± SD). Delayed administration of propofol 90 and 180 min after training or immediate posttraining administration of the benzodiazepine midazolam or the barbiturate pentobarbital did not significantly alter retention. Conclusions These findings indicate that propofol, in contrast to other commonly used sedatives, enhances emotional memory consolidation when administered immediately after a stressful event by enhancing endocannabinoid signaling.

Sleep, neural reuse, and memory consolidation processes

2010 ◽  
Vol 33 (4) ◽  
pp. 273-273
Author(s):  
William Fishbein ◽  
Hiuyan Lau ◽  
Rafael DeJesús ◽  
Sara Elizabeth Alger
Keyword(s):  
Cognitive Processes ◽  
Memory Consolidation ◽  
Neural Circuits ◽  
Neural Circuitry ◽  
Evolutionary Adaptation ◽  
Sleep State ◽  
Memory Processes ◽  
Brain System ◽  
Neural Reuse

AbstractNeural reuse posits development of functional overlap in brain system circuits to accommodate complex evolutionary functions. Evolutionary adaptation evolved neural circuits that have been exploited for many uses. One such use is engaging cognitive processes in memory consolidation during the neurobiological states of sleep. Neural reuse, therefore, should not be limited to neural circuitry, but be extended to include sleep-state associated memory processes.

ChemInform Abstract: Memory Consolidation of Pavlovian Fear Conditioning: A Cellular and Molecular Perspective

ChemInform ◽  
2010 ◽  
Vol 32 (51) ◽  
pp. no-no ◽  
Author(s):  
G. E. Schafe ◽  
K. Nader ◽  
H. T. Blair ◽  
J. E. LeDoux
Keyword(s):  
Fear Conditioning ◽  
Memory Consolidation ◽  
Pavlovian Fear Conditioning
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