Memory Inhibition Research Articles

Leveraging memory suppression from a goal-directed perspective to regain control over alcohol consumption.

Leveraging memory suppression from a goal-directed perspective to regain control over alcohol consumption.

Communist Prison Camps as Sites of Memory and Legacies of Dissent: Belene and Goli Otok in Bulgarian and Croatian Cultural Memory

This article investigates how two Communist forced labour camps, Belene in Bulgaria and Goli Otok in Croatia, became sites of memory and remain icons of political repression and state-organized torture. The article discusses how the public memory of the two camps has been shaped through vivid depictions in former inmates’ memoirs and in works of fiction. It analyzes recent debates about the preservation and institutionalization of these sites of memory and about what, whom, and how to commemorate. As a further step, it investigates how the camp sites have attracted visitors interested in so-called dark tourism. The article explores the creation of a literary tradition of memory by tracing the writings that have helped to establish Belene and Goli Otok as sites of memory of political repression in Bulgaria and Croatia, and it examines the processes involved in the construction of the physical sites as heritage sites and tourist attractions.

A novel hypothesis on mechanisms and potential role of host cell membrane proteins incorporated into the viral envelope in alloreactivity

Despite significant advances in transplantation medicine, allograft rejection remains a major challenge in clinical practice. The preexistence of alloreactive lymphocytes is a primary cause of allograft rejection. The forthcoming challenges in clinical transplantation will involve the suppression or eradication of allospecific memory T cells. Viral infections and allograft rejection interact in multiple ways that can compromise the survival of transplanted organs. Evidence is currently accumulating on the incorporation of HLA antigens and other host cell plasma membrane molecules into the viral envelope. A consequence of the viral envelope displaying the HLA signature acquired from the plasma membrane of infected cells is that when virions are transmitted to the next host, the newly infected person became exposed to allogeneic molecules stimulating alloimmunity and generating memory to alloantigens. Thus, successive exposure to viral infections throughout life could potentially contribute to the development of alloimmunity and the generation of numerous clones of memory alloreactive lymphocytes. In this paper a novel hypothesis is developed on the potential role and mechanisms of alloresponse induced by human spread of enveloped viruses. As this hypothesis could aid in the knowledge of preexisting alloreactivity, additional research into the intricacies of virion-incorporated host cell proteins is necessary. A deeper understanding of this dynamic interaction will help promote advances in the long-term acceptance of transplants.

Trying to forget alcohol: Brain mechanisms underlying memory suppression in young binge drinkers

People are able to voluntarily suppress unwanted thoughts or memories, a phenomenon known as suppression-induced forgetting or memory suppression. Despite harmful alcohol use, such as binge drinking, has been linked to impaired inhibitory control (IC) and augmented alcohol-cue reactivity, no study to date has assessed memory inhibition abilities towards alcohol-related cues in binge drinkers (BDs). Thus, the present preregistered study aimed to evaluate the behavioral and neurofunctional mechanisms associated with memory inhibition, specifically those related to the suppression of alcohol-related memories, in young BDs. For this purpose, electroencephalographic activity was recorded in eighty-two college students aged between 18 and 24 years old from the University of Minho (50% females; 40 non/low-drinkers [N/LDS] and 42 BDs) while they performed the Think/No-Think Alcohol task. Brain functional connectivity (FC) was calculated using the phase locking value and, subsequently, a dynamic seed-based analysis was conducted to explore the FC patterns between IC and memory networks. Comparatively to N/LDs, BDs exhibited decreased alpha-band FC between the anterior cingulate cortex and the left fusiform gyrus during attempts to suppress non-alcohol memories, accompanied by unsuccessful forgetting of those memories. Conversely, BDs displayed augmented gamma-band FC between the IC network and memory regions –i.e., hippocampus, parahippocampus and fusiform gyrus- during suppression of alcohol-related memories. Inhibitory abnormalities in BDs may lead to hypoconnectivity between IC and memory networks and deficient suppression of non-alcohol-related memories. However, while suppressing highly salient and reward-predicting stimuli, such as alcohol-related memories, BDs display a hyperconnectivity pattern between IC and memory networks, likely due to their augmented attention towards intrusive alcoholic memories and the attempts to compensate for potential underlying IC deficits. These findings hold important implications for alcohol research and treatment, as they open up new avenues for reducing alcohol use by shifting the focus to empowering suppression/control over alcohol-related memories. Clinical trial registration[http://www.ClinicalTrials.gov], identifier [NCT05237414].

Tackling addictive behaviors through memory suppression: A scoping review and perspective.

Forgetting is often viewed as a human frailty. However, over the years, it has been considered an adaptive process that allows people to avoid retrieval of undesirable memories, preventing them from suffering and discomfort. Evidence shows that the ability to suppress memories is affected by several psychopathological conditions characterized by persistent unwanted thoughts, including anxiety and posttraumatic stress disorders. Nevertheless, memory suppression (MS) mechanisms in addiction-a clinical condition characterized by recurrent drug-related thoughts that contribute to repeated drug use-have received little attention so far. Addiction theories reveal that drugs change behavior by working on memory systems, particularly on declarative memory, which is related to the retrieval and encoding of drug-related memories. In this review, the main behavioral and neurofunctional findings concerning the Think/No-Think task-an adaptation of the classical Go/No-Go tasks typically used to evaluate the suppression of motor response-are presented. We then show how the memory system can be involved in the craving or anticipation/preoccupation stage of the addiction cycle. Subsequently, the study of MS in the context of addictive behaviors is highlighted as a promising approach for gaining knowledge about the mechanisms contributing to the continuation of addiction. Finally, we discuss how interventions aiming to strengthen this ability could impact the anticipation/preoccupation stage by (i) reducing the accessibility of drug-related memories, (ii) decreasing craving and attention toward drug-related stimuli, and (iii) improving overall inhibition abilities. In conclusion, this review aims to illustrate how the study of MS may be a valuable approach to enhance our understanding of substance use disorders by unveiling the underlying cognitive and neural mechanisms involved, which could have important implications for addiction treatment.

Observing the suppression of individual aversive memories from conscious awareness.

When reminded of an unpleasant experience, people often try to exclude the unwanted memory from awareness, a process known as retrieval suppression. Here we used multivariate decoding (MVPA) and representational similarity analyses on EEG data to track how suppression unfolds in time and to reveal its impact on item-specific cortical patterns. We presented reminders to aversive scenes and asked people to either suppress or to retrieve the scene. During suppression, mid-frontal theta power within the first 500ms distinguished suppression from passive viewing of the reminder, indicating that suppression rapidly recruited control. During retrieval, we could discern EEG cortical patterns relating to individual memories-initially, based on theta-driven visual perception of the reminders (0 to 500ms) and later, based on alpha-driven reinstatement of the aversive scene (500 to 3000ms). Critically, suppressing retrieval weakened (during 360 to 600ms) and eventually abolished item-specific cortical patterns, a robust effect that persisted until the reminder disappeared (780 to 3000ms). Representational similarity analyses provided converging evidence that retrieval suppression weakened the representation of target scenes during the 500 to 3000ms reinstatement window. Together, rapid top-down control during retrieval suppression abolished cortical patterns of individual memories, and precipitated later forgetting. These findings reveal a precise chronometry on the voluntary suppression of individual memories.

Forgetting Atrocity in East Africa

East Africa presents striking examples of the different ways in which states may seek to promote forgetting through control or suppression of memories of mass violence. In Rwanda, the 1994 genocide is intensively memorialized, yet violence committed by the ruling party is not part of the official history. In Burundi, a power-sharing deal to end a civil war led to the erasure of memory through deliberate neglect. In Kenya, sites of terrorist violence have been fortified and reopened in the name of resilience—a form of triumphalist amnesia. Yet in each country, citizens practice informal varieties of commemoration.

Acute stress impairs intentional memory suppression through aberrant prefrontal cortex activation in high trait ruminators

ObjectiveResearch shows that the effect of acute stress on intentional memory suppression could be modulated by individual differences in psychological traits. However, whether acute stress distinctly affects intentional memory suppression in high trait ruminators, a high at-risk group of stress-related disorders, and the neural correlations, remains unclear. Method55 healthy college students were divided into high and low trait ruminators (HTR and LTR), Following stress manipulation, a Think/No Think task assessed the memory suppression performance. Functional near-infrared spectroscopy was applied to explore the neural correlates. Psychophysiological interaction analyses were used to assess how the functional connectivity between a seed region and another brain region was modulated by tasks during memory suppression, further mediating memory suppression performance and state rumination. ResultsThe HTR exhibited poorer memory suppression performance than the LTR under the stress condition. Aberrant activation patterns and task-modulated functional connectivity in the dorsal prefrontal cortex (DLPFC) and superior temporal gyrus (STG) were observed only in the HTR during memory suppression under the stress condition. The effect of memory suppression performance on the state rumination of individuals was significantly mediated by the task-modulated functional connectivity between the DLPFC and STG. ConclusionsThe findings could provide insights for prevention or early intervention in the development of stress-related disorders in HTR.

The Local Memory of Repression, and Who Fights

abstract: How does the local memory of past repression affect whether individuals fight for or rebel against the government perpetrator? The authors theorize how information about past repression is transmitted across generations to shape long-run patterns of loyalty and rebellion toward the state. To assess this argument, they study how the legacies of the 1845–49 Irish Potato Famine affected the decisions of subsequent generations of Irishmen to fight for or against Britain. Leveraging data on more than 150,000 Irish combatants, the authors show that individuals in places more severely affected by the Famine fought in the pro-British Irish Militia and the British military in World War I at lower rates. By contrast, those individuals rebelled against Britain at higher rates. Additional quantitative analysis provides evidence consistent with the theoretical argument: constituencies more severely affected by the Famine were more likely to vote for the pro-Irish, anti-British Sinn Féin Party. This article demonstrates how the local memory of past repression can play a crucial role in shaping long-run patterns of participation in conflict.

Nucleation and spreading maintain Polycomb domains every cell cycle

Gene repression by the Polycomb pathway is essential for metazoan development. Polycomb domains, characterized by trimethylation of histone H3 lysine 27 (H3K27me3), carry the memory of repression and hence need to be maintained to counter the dilution of parental H3K27me3 with unmodified H3 during replication. Yet, how locus-specific H3K27me3 is maintained through replication is unclear. To understand H3K27me3 recovery post-replication, we first define nucleation sites within each Polycomb domain in mouse embryonic stem cells. To map dynamics of H3K27me3 domains across the cell cycle, we develop CUT&Flow (coupling cleavage under target and tagmentation with flow cytometry). We show that post-replication recovery of Polycomb domains occurs by nucleation and spreading, using the same nucleation sites used during de novo domain formation. By using Polycomb repressive complex 2 (PRC2) subunit-specific inhibitors, we find that PRC2 targets nucleation sites post-replication independent of pre-existing H3K27me3. Thus, competition between H3K27me3 deposition and nucleosome turnover drives both de novo domain formation and maintenance during every cell cycle.

Overexpression of the limk1 Gene in Drosophila melanogaster Can Lead to Suppression of Courtship Memory in Males.

Courtship suppression is a behavioral adaptation of the fruit fly. When majority of the females in a fly population are fertilized and non-receptive for mating, a male, after a series of failed attempts, decreases its courtship activity towards all females, saving its energy and reproductive resources. The time of courtship decrease depends on both duration of unsuccessful courtship and genetically determined features of the male nervous system. Thereby, courtship suppression paradigm can be used for studying molecular mechanisms of learning and memory. p-Cofilin, a component of the actin remodeling signaling cascade and product of LIM-kinase 1 (LIMK1), regulates Drosophila melanogaster forgetting in olfactory learning paradigm. Previously, we have shown that limk1 suppression in the specific types of nervous cells differently affects fly courtship memory. Here, we used Gal4 > UAS system to induce limk1 overexpression in the same types of neurons. limk1 activation in the mushroom body, glia, and fruitless neurons decreased learning index compared to the control strain or the strain with limk1 knockdown. In cholinergic and dopaminergic/serotoninergic neurons, both overexpression and knockdown of limk1 impaired Drosophila short-term memory. Thus, proper balance of the limk1 activity is crucial for normal cognitive activity of the fruit fly.

Suppression of Memory as Totalitarian Strategy: A Critique of Yoko Ogawa’s The Memory Police

In the contemporary world, activities of the people have been monitored and scrutinised by the ever strong vigilant governments. The Fascist governments, in particular, are changing the dynamics of the countries as well as the world by moulding and shaping the minds of people according to their objectives. The opponents of the state are silenced or liquidated. The present paper on renowned Japanese writer Yoko Ogawa’s science fiction work, The Memory Police (2019) has been done to highlight similar issues. The article is divided into three sections. The first section of the article examines how totalitarian regimes function, particularly by playing upon the minds and memories of its citizens. The paper also points out as how people engage with memory as a weapon of protest and as a near-sentient being are confronted with an iniquitous opposition whose main objective is to destroy it. The second section focuses how the psychological toll of forgetting is manifested in the physical world. For instance, when objects vanish from reality, they vanish from memory too, and vice versa. Finally, in the third section, analogies are drawn between the metaphoric cosmos of the novel and in the previously witnessed progressively hypernationalistic and dictatorial governments acquiring control over the world.

Biphasic Npas4 expression promotes inhibitory plasticity and suppression of fear memory consolidation in mice

Long-term memories are believed to be encoded by unique transcriptional signatures in the brain. The expression of immediate early genes (IEG) promotes structural and molecular changes required for memory consolidation. Recent evidence has shown that the brain is equipped with mechanisms that not only promote, but actively constrict memory formation. However, it remains unknown whether IEG expression may play a role in memory suppression. Here we uncovered a novel function of the IEG neuronal PAS domain protein 4 (Npas4), as an inducible memory suppressor gene of highly salient aversive experiences. Using a contextual fear conditioning paradigm, we found that low stimulus salience leads to monophasic Npas4 expression, while highly salient learning induces a biphasic expression of Npas4 in the hippocampus. The later phase requires N-methyl-D-aspartate (NMDA) receptor activity and is independent of dopaminergic neurotransmission. Our in vivo pharmacological and genetic manipulation experiments suggested that the later phase of Npas4 expression restricts the consolidation of a fear memory and promote behavioral flexibility, by facilitating fear extinction and the contextual specificity of fear responses. Moreover, immunofluorescence and electrophysiological analysis revealed a concomitant increase in synaptic input from cholecystokinin (CCK)-expressing interneurons. Our results demonstrate how salient experiences evoke unique temporal patterns of IEG expression that fine-tune memory consolidation. Moreover, our study provides evidence for inducible gene expression associated with memory suppression as a possible mechanism to balance the consolidation of highly salient memories, and thereby to evade the formation of maladaptive behavior.

Ayahuasca-enhanced extinction of fear behaviour: Role of infralimbic cortex 5-HT2A and 5-HT1A receptors.

Ayahuasca (AYA) is a botanical psychedelic with promising results in observational and small clinical trials for depression, trauma and drug use disorders. Its psychoactive effects primarily stem from N,N-dimethyltryptamine (DMT). However, there is a lack of research on how and where AYA acts in the brain. This study addressed these questions by examining the extinction of aversive memories in AYA-treated rats. We focused on the 5-HT1A and 5-HT2A receptors, as DMT exhibits a high affinity for both of them, along with the infralimbic cortex in which activity and plasticity play crucial roles in regulating the mnemonic process under analysis. A single oral treatment with AYA containing 0.3 mg·kg-1 of DMT increased the within-session extinction of contextual freezing behaviour without affecting its recall. This protocol, when repeated twice on consecutive days, enhanced extinction recall. These effects were consistent for both 1- and 21-day-old memories in males and females. AYA effects on fear extinction were independent of changes in anxiety and general exploratory activity: AYA- and vehicle-treated animals showed no differences when tested in the elevated plus-maze. The 5-HT2A receptor antagonist MDL-11,939 and the 5-HT1A receptor antagonist WAY-100635 infused into the infralimbic cortex respectively blocked within- and between-session fear extinction effects resulting from repeated oral administration of AYA. Our findings highlight complementary mechanisms by which AYA facilitates the behavioural suppression of aversive memories in the rat infralimbic cortex. These results suggest potential beneficial effects of AYA or DMT in stress-related disorders.

From infamy to truth. Epistemic coloniality and knowledges in resistance: an approach to the cases of Inés Fernández Ortega and Valentina Rosendo Cantú

PurposeThe purpose of the article is to show the regime of truth in the institutional commissions that have the objective of restoring history by establishing a democratic, equitable, comprehensive, inclusive and fair criterion against the attempts of re-victimization and suppression of memory that Western political and cultural traditions have installed through their mechanisms of power.Design/methodology/approachBased on the analysis of the cases of Inés Fernández Ortega and Valentina Rosendo Cantú, they establish the material conditions from which prejudices and hegemonic stereotypes are intertwined to reproduce serious violations of human rights in democratic political and epistemic frameworks. The colonial function of the truth commissions in Mexico is analyzed, which are presented as mechanisms for social development, political and colonial reproduction of liberal democracy.FindingsThe qualitative results allow considering the way in which the different truth commissions in Mexico have been strongly linked to epistemic mechanisms in which truth and justice favor the reproduction of established relationships based on race, social class and gender. Especially in the so-called democratic transition, violence, truth and justice come together to highlight power relations in situations that have been disavowed by the intelligentsia.Research limitations/implicationsThe limitations of the research are found in the historical configuration of the truth commissions in Mexico. The data, references and assessments are crossed by the initial function of the truth commissions and the establishment of apparatuses and mechanisms based on transitional justice. Based on this, it can be considered a methodological oversight to shift the analysis of truth commissions toward a critical assessment of the truth as a regime of government and hegemonic and colonization criteria from two very specific cases.Originality/valueThe originality of the work is found in the critical discernment of truth as a political category and the coloniality of power.

Memory, Religion, and Authoritarianism in Post (1994)-Genocide Rwanda

This article attempts to theorise governmental efforts of the Kagame regime to construct a common national identity that precariously hinges on the adoption of an official revisionist history. Guided by Jan Assmann’s theory of cultural memory and Maurice Halbwachs’ collective memory, it may be argued the government’s official narrative of Rwanda’s idyllic history is a strategy for securing Rwanda’s future by linking it to an ancestral past. This narrative is largely supported by museums and the frozen memories of Tutsi returnees — to the exclusion of competing narratives — as materialised and publicly disseminated through traditional dances and tandemly pursued through private spaces through infiltration and closure of churches and mosques. However, per Rebekah Phillips DeZalia, a new version of history must successfully replace the former in the personal narratives of the people and not simply control public discourse through a top-down approach. Hence, the Kagame regime is also utilising a bottom-up strategy of infiltrating day-to-day, intimate spaces — one of which is religious spaces by both exploiting and curbing religious influence, appropriating religious language, and referencing the divine right of kings — all which are designed to sustain public confidence in the possibility of post-1994 genocide reconciliation and to realise Kagame’s vision of a unified and prosperous Rwanda. The regime’s strategy involves inverting the overall passage of personal memory to collective memory to history as well as repressing memory in official memorials by excluding narratives that contradict or do not legitimise the Kagame regime’s agenda. This tandem manipulation and suppression of memory is aided by the aggressive campaign of church and mosque infiltrations as well as closures, respectively, which may be functionally understood using Thomas Luckmann’s notions of invisible religion (Rwandan government) as competing with visible religions (Christianity and Islam). These government strategies are detrimental to the trauma-coping potential of visible religions and undermines reconciliation — highlighting the fragile architecture of Kagame’s authoritarian vision for peace.

Suppressing memory associations impacts decision-making preference: Evidence from the think/no-think paradigm

Recent research has suggested that episodic memory can guide our decision-making. Forgetting is one essential characteristic of memory. If certain memories are suppressed to be forgotten, decisions that rely on such memories should be impacted. So far, little research has examined whether suppression of episodic memory would impact decision-making. In the current pre-registered study, the effect of memory suppression on subsequent reinforcement decision-making was examined by combining the Think/No-think paradigm and a reinforcement decision-making task. We found that suppressing memories of learned associations significantly impaired recollected memories of those associations, and participants’ decision bias disappeared after their memory associations were suppressed. Furthermore, the more memory associations participants recalled, the higher decision preferences they exhibited. Our findings provide additional support for the role of episodic memory in reinforcement decision-making, and suggest that suppressing memory associations can lead to behavioral consequences.

Memory suppression devalues food reward and can predict long-term changes in emotional eating

Memory retrieval suppression is a cognitive process that involves intentional suppression of certain memories coming to consciousness. It not only disrupts episodic memories but also devaluates the affective response associated with those memories. Thus, memory suppression training, akin to other inhibitory control trainings, could potentially serve as a promising tool to devaluate reward response to appetizing food cues. However, to the best of our knowledge, there has been few studies directly investigating devaluation effects of memory suppression training on reward response to food-related targets, and these potential benefits among emotional eaters remains unclear. Thus, the current study used food-specific Think/No-Think task to investigate the devaluation effects of memory suppression on food-related thoughts. The outcome variables, namely food reward response and food choice, were assessed using the Food Rating and Choice task. Thirty-nine young female participants were enrolled, with 20 displaying low emotional eating tendencies and 19 exhibiting high tendencies. Direct comparisons between these two groups were conducted. After one-year follow-up, thirty-six of the original participants returned to the laboratory and finished measures of emotional eating again. As hypothesized, suppressing the retrieval of food-related targets not only disrupts the corresponding memories, but also reduces the hedonic basis in food decision-making. Notably, these devaluation effects were only observed among those low in emotional eating tendencies. Additionally, successful memory suppression could predict changes in emotional eating tendencies at one-year follow-up. These findings offered valuable insights into the potential modulation of food choices and emotional eating over time.

Commemorative Project “Kovalevsky Forest”: Conflicts of Mnemonic Actors and Strategies for Resolving Them (2001–2022)

The article examines the conflicts between mnemonic actors regarding the commemorative project of the Kovalevsky Forest as a place to perpetuate the memory of the victims of the Red Terror of the 1920s. Based on the ideas of O. Dwyer and D. Alderman on the study of memorial objects, the author in the article analyzes the conflicts between actors regarding the level of their involvement in the formation of the project and the figures included in it. The author comes to the conclusion that mnemonic actors interested in overcoming the oblivion of the Red Terror sought to create a mythologized version of the past in the Kovalevsky Forest for visitors for whom the memory of repression, terror and its victims was carried outside the city borders. In the process of development of the project, the Kovalevsky Forest becomes a flexible space with many myths. To successfully implement the project, the actors were ready to build their relationships as mutually accepting and agreed to include many narratives in it.

Suppression and facilitation of streetscape memory caused by cognitive offloading

Suppression and facilitation of streetscape memory caused by cognitive offloading