Memory Integration as a Challenge to the Consolidation/Reconsolidation Hypothesis: Similarities, Differences and Perspectives

Gisquet-Verrier, Pascale; Riccio, David C.

doi:10.3389/fnsys.2018.00071

Cited by 19 publications

(19 citation statements)

References 110 publications

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“…The integration concept, suggested by Gisquet-Verrier and Riccio (2019), however, may account for our findings. According to this concept, reactivated memories are labile and can integrate new information.…”

Section: Discussioncontrasting

confidence: 59%

Reactivation of the Unconditioned Stimulus Inhibits the Return of Fear Independent of Cortisol

Drexler

Merz

Lissek

et al. 2019

Front. Behav. Neurosci.

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Reconsolidation is the post-retrieval stabilization of memories, a time-limited process during which reactivated (i.e., retrieved) memories can be updated with new information, become stronger or weaker, depending on the specific treatment. We have previously shown that the stress hormone cortisol has an enhancing effect on the reconsolidation of fear memories in men. This effect was specific, i.e., limited to the conditioned stimulus (CS) that was reactivated, and did not generalize to other previously reinforced, but not reactivated CS. Based on these results, we suggested that cortisol plays a critical role in the continuous strengthening of reactivated emotional memories, contributing to their persistence and robustness. In the current study, we aimed to achieve a more generalized reconsolidation enhancement using an alternative reactivation method, i.e., by a low-intensity unconditioned stimulus (UCS) presentation instead of the more common unreinforced CS presentation. In previous studies, UCS reactivation was shown to lead to a more generalized reconsolidation effect. Therefore, we hypothesized that the combination of cortisol treatment and UCS reactivation would lead to an enhanced fear memory reconsolidation, which would generalize from previously reinforced CS to stimuli that resemble it. We tested 75 men in a 3-day fear conditioning paradigm: fear acquisition training on day 1; UCS reactivation/no reactivation and pharmacological treatment (20 mg hydrocortisone/placebo) on day 2; extinction training, reinstatement and test (of original and modified stimuli) on day 3. In contrast to our hypothesis, UCS reactivation prevented the return of fear [observed in skin conductance responses (SCR)] regardless of the pharmacological manipulation: while reinstatement to the original CS was found in the no-reactivation group, both reactivation groups (cortisol and placebo) showed no reinstatement. As the only methodological difference between our previous study and the current one was the reactivation method, we focus on UCS reactivation as the main explanation for these unexpected findings. We suggest that the robust prediction error generated by the UCS reactivation method (as opposed to CS reactivation), combined with the lower UCS intensity, has by itself weakened the emotional value of the UCS, thus preventing the return of fear to the CS that was associated with it. We call for future research to support these findings and to examine the potential of this reactivation method, or variations thereof, as a tool for therapeutic use.

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Section: Discussioncontrasting

confidence: 59%

Reactivation of the Unconditioned Stimulus Inhibits the Return of Fear Independent of Cortisol

Drexler

Merz

Lissek

et al. 2019

Front. Behav. Neurosci.

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show abstract

“…In rats, it decreases anxiety 17,65,67,68 and attenuates conditioned fear by inhibiting, via its receptors in the central amygdala, the excitatory flow from the amygdala to brainstem sites that mediates fear responses 15,69 . In view of these properties, and of the general agreement that memory reactivation opens a malleability window during which any newly presented information can be integrated within the original memory representation 70,71 , we propose that prereactivation oxytocin treatment leads to the formation of a novel, less traumatic, fear memory representation which mediates resilience to trauma.…”

Section: Emotional Remodeling With Oxytocin: What Mechanisms?mentioning

confidence: 97%

Emotional remodeling with oxytocin durably rescues trauma-induced behavioral and neuro-morphological changes in rats: a promising treatment for PTSD

et al. 2020

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Recent evidence indicates that reactivated memories are malleable and can integrate new information upon their reactivation. We injected rats with oxytocin to investigate whether the delivery of a drug which dampens anxiety and fear before the reactivation of trauma memory decreases the emotional load of the original representation and durably alleviates PTSD-like symptoms. Rats exposed to the single prolonged stress (SPS) model of PTSD were classified 15 and 17 days later as either resilient or vulnerable to trauma on the basis of their anxiety and arousal scores. Following 2 other weeks, they received an intracerebral infusion of oxytocin (0.1 µg/1 µL) or saline 40 min before their trauma memory was reactivated by exposure to SPS reminders. PTSD-like symptoms and reactivity to PTSD-related cues were examined 3-14 days after oxytocin treatment. Results showed that vulnerable rats treated with saline exhibited a robust PTSD syndrome including increased anxiety and decreased arousal, as well as intense fear reactions to SPS sensory and contextual cues. Exposure to a combination of those cues resulted in c-fos hypo-activation and dendritic arbor retraction in prefrontal cortex and amygdala neurons, relative to resilient rats. Remarkably, 83% of vulnerable rats subjected to oxytocin-based emotional remodeling exhibited a resilient phenotype, and SPS-induced morphological alterations in prelimbic cortex and basolateral amygdala were eliminated. Our findings emphasize the translational potential of the present oxytocin-based emotional remodeling protocol which, when administered even long after the trauma, produces deep reprocessing of traumatic memories and durable attenuation of the PTSD symptomatology.

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“…Depending on the information available at that time, memories can be updated, strengthened (by coherent information), disrupted (by inco herent information resulting from, for exam ple, amnesic treatments or interference) or greatly altered (false memory). We have des cribed evidence 5,6 showing that performance disruption due to posttraining amnesic treatments mainly results from impairments in retrieval that are induced by contextual differences between training and testing.…”

mentioning

confidence: 97%

Comparing integration and contextual binding accounts of memory impairment

Gisquet-Verrier

Riccio

2019

Nat Rev Neurosci

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Memory Integration as a Challenge to the Consolidation/Reconsolidation Hypothesis: Similarities, Differences and Perspectives

Cited by 19 publications

References 110 publications

Reactivation of the Unconditioned Stimulus Inhibits the Return of Fear Independent of Cortisol

Reactivation of the Unconditioned Stimulus Inhibits the Return of Fear Independent of Cortisol

Emotional remodeling with oxytocin durably rescues trauma-induced behavioral and neuro-morphological changes in rats: a promising treatment for PTSD

Comparing integration and contextual binding accounts of memory impairment

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