Biased memory retrieval in the service of shared reality with an audience: The role of cognitive accessibility.

After communicators have tuned a message about a target person's behaviors to their audience's attitude, their recall of the target's behaviors is often evaluatively consistent with their audience's attitude. This audience-congruent recall bias has been explained as the result of the communicators' creation of a shared reality with the audience, which helps communicators to achieve epistemic needs for confident judgments and knowledge. Drawing on the "Relevance Of A Representation" (ROAR) model of cognitive accessibility from motivational truth relevance, we argue that shared reality increases the accessibility of information consistent (vs. inconsistent) with the audience's attitude. We tested this prediction with a novel reaction time task in three experiments employing the saying-is-believing paradigm. Faster reactions to audience-consistent (vs. audience-inconsistent) information were found for trait information but not for behavioral information. Thus, an audience-congruent accessibility bias emerged at the level at which impressions and judgments of other persons are typically organized. Consistent with a shared-reality account, the audience-consistent accessibility bias correlated with experienced shared reality with the audience about the target person and with epistemic trust in the audience. These findings support the view that the creation of shared reality with an audience triggers a basic cognitive mechanism that facilitates the retrieval of audience-congruent (vs. audience-incongruent) trait information about a target person. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The effect of a visuospatial interference intervention on posttraumatic intrusions: a cross-over randomized controlled trial.

Background: Intrusive memories form a core symptom of Posttraumatic Stress Disorder (PTSD). Based on concepts of visuospatial interference and memory-updating accounts, technological innovations aim to attenuate such intrusions using visuospatial interventions.Objective: This study aims to test the effect of a visuospatial Tetris-based intervention versus a verbal condition (Wiki) and a never-targeted control (no intervention) on intrusion frequency.Method: A randomized crossover trial was conducted including N = 38 PTSD patients who had at least 3 distinct intrusive memories of trauma. After both 2 weeks (intervention 1) and 4 weeks (intervention 2), one of the three memories was randomly selected and either the visuospatial intervention (memory reminder of a traumatic memory + Tetris) or verbal condition (reading a Wikipedia article + answering questions) was performed on their first memory in randomized order. In the week 4 session, the patient conducted the other intervention condition on their second memory (crossover). The third memory was never targeted (no intervention). Daily occurrence of intrusions over 8 weeks was collected using a diary and analysed using mixed Poisson regression models.Results: Overall, there was no significant reduction in intrusion frequency from either intervention compared to each other, and to no intervention control (relative risk Tetris/Wiki: 0.947; p = .31; relative risk no intervention/Tetris: 1.060; p = .15; relative risk no intervention/Wiki: 1.004; p = .92).Conclusions: There was no effect of either intervention on intrusions when administered in a crossover design where participants received both interventions. Design shortcomings and consequences for future studies are discussed.

Visuospatial interventions, including the computer game Tetris, have been studied as a potential means to decrease intrusive memories, a core feature of Posttraumatic Stress Disorder.In this study, two interventions are tested in a crossover design with patients with intrusive memories after traumatic experiences.There was no effect of either the visuospatial intervention or the verbal condition in this design.

Maintenance of color memoranda in activity-quiescent working memory states: Evidence from impulse perturbation.

In the present study, we used an impulse perturbation method to probe working memory maintenance of colors in neurally active and activity-quiescent states, focusing on a set of pre-registered analyses. We analyzed the electroencephalograph (EEG) data of 30 participants who completed a delayed match-to-sample working memory task, in which one of the two items that were presented was retro-cued as task relevant. The analyses revealed that both cued and uncued colors were decodable from impulse-evoked activity, the latter in contrast to previous reports of working memory for orientation gratings. Decoding of colors from oscillations in the alpha band showed that cued items could be decoded therein whereas uncued items could not. Overall, the outcomes suggest that subtle differences exist between the representation of colors, and that of stimuli with spatial properties, but the present results also demonstrate that regardless of their specific neural state, both are accessible through visual impulse perturbation.

Hippocampal subfield plasticity is associated with improved spatial memory.

Physical exercise studies are generally underrepresented in young adulthood. Seventeen subjects were randomized into an intervention group (24.2 ± 3.9 years; 3 trainings/week) and 10 subjects into a passive control group (23.7 ± 4.2 years), over a duration of 6 months. Every two months, performance diagnostics, computerized spatial memory tests, and 3 Tesla magnetic resonance imaging were conducted. Here we find that the intervention group, compared to controls, showed increased cardiorespiratory fitness, spatial memory performance and subregional hippocampal volumes over time. Time-by-condition interactions occurred in right cornu ammonis 4 body and (trend only) dentate gyrus, left hippocampal tail and left subiculum. Increases in spatial memory performance correlated with hippocampal body volume changes and, subregionally, with left subicular volume changes. In conclusion, findings support earlier reports of exercise-induced subregional hippocampal volume changes. Such exercise-related plasticity may not only be of interest for young adults with clinical disorders of hippocampal function, but also for sedentary normal cohorts.

Exploring the Remediation of Behavioral Disturbances of Spatial Cognition in Community-Dwelling Senior Citizens with Mild Cognitive Impairment via Innovative Technological Apparatus (BDSC-MCI Project): Protocol for a Prospective, Multi-Center Observational Study.

Spatial navigation (SN) has been reported to be one of the first cognitive domains to be affected in Alzheimer's disease (AD), which occurs as a result of progressive neuropathology involving specific brain areas. Moreover, the epsilon 4 isoform of apolipoprotein-E (APOE-ε4) has been associated with both sporadic and familial late-onset AD, and patients with mild cognitive impairment (MCI) due to AD are more likely to progressively deteriorate. Spatial navigation performance will be examined on a sample of 76 community-dwelling senior citizens (25 healthy controls; 25 individuals with subjective cognitive decline (SCD); and 26 patients with MCI due to AD) via a virtual computer-based task (i.e., the AppleGame) and a naturalistic task (i.e., the Detour Navigation Test-modified version) for which a wearable device with sensors will be used for recording gait data and revealing physiological parameters that may be associated with spatial disorientation. We expect that patients with MCI due to AD and APOE-ε4 carriers will show altered SN performances compared to individuals with SCD and healthy controls in the experimental tasks, and that VR testing may predict ecological performance. Impaired SN performances in people at increased risk of developing AD may inform future cognitive rehabilitation protocols for counteracting spatial disorientation that may occur during elders' traveling to unfamiliar locations. The research protocol has been approved by the Ethics Committee of the Istituto Auxologico Italiano. Findings will be published in peer-reviewed medical journals and discussed in national and international congresses.

Grid codes underlie multiple cognitive maps in the human brain.

Grid cells fire at multiple positions that organize the vertices of equilateral triangles tiling a 2D space and are well studied in rodents. The last decade witnessed rapid progress in two other research lines on grid codes-empirical studies on distributed human grid-like representations in physical and multiple non-physical spaces, and cognitive computational models addressing the function of grid cells based on principles of efficient and predictive coding. Here, we review the progress in these fields and integrate these lines into a systematic organization. We also discuss the coordinate mechanisms of grid codes in the human entorhinal cortex and medial prefrontal cortex and their role in neurological and psychiatric diseases.

Deep-brain stimulation of the human nucleus accumbens-medial septum enhances memory formation.

Deep-brain stimulation (DBS) is a potential novel treatment for memory dysfunction. Current attempts to enhance memory focus on stimulating human hippocampus or entorhinal cortex. However, an alternative strategy is to stimulate brain areas providing modulatory inputs to medial temporal memory-related structures, such as the nucleus accumbens (NAc), which is implicated in enhancing episodic memory encoding. Here, we show that NAc-DBS improves episodic and spatial memory in psychiatric patients. During stimulation, NAc-DBS increased the probability that infrequent (oddball) pictures would be subsequently recollected, relative to periods off stimulation. In a second experiment, NAc-DBS improved performance in a virtual path-integration task. An optimal electrode localization analysis revealed a locus spanning postero-medio-dorsal NAc and medial septum predictive of memory improvement across both tasks. Patient structural connectivity analyses, as well as NAc-DBS-evoked hemodynamic responses in a rat model, converge on a central role for NAc in a hippocampal-mesolimbic circuit regulating encoding into long-term memory. Thus, short-lived, phasic NAc electrical stimulation dynamically improved memory, establishing a critical on-line role for human NAc in episodic memory and providing an empirical basis for considering NAc-DBS in patients with loss of memory function.

The multi-level outcome study of psychoanalysis for chronically depressed patients with early trauma (MODE): rationale and design of an international multicenter randomized controlled trial.

BACKGROUND: Whether and how psychotherapies change brain structure and function is unknown. Its study is of great importance for contemporary psychotherapy, as it may lead to discovery of neurobiological mechanisms that predict and mediate lasting changes in psychotherapy, particularly in severely mentally ill patients, such as those with chronic depression. Previous studies have shown that psychoanalytic psychotherapies produce robust and enduring improvements in not only symptom severity but also personality organization in patients who have chronic depression and early life trauma, especially if therapy is delivered at a high weekly frequency. METHODS/DESIGN: Patients with chronic major depression and a history of early life trauma will be recruited, assessed, and treated across 3 international sites: Germany, Switzerland, and the United States. They will be randomized to one of two treatment arms: either (1) once weekly psychoanalytic psychotherapies, or (2) 3-4 times weekly psychoanalytic psychotherapies. They will have full clinical characterization as well as undergo MRI scanning at study baseline prior to randomization and again one year later. A group of matched healthy controls will undergo similar assessments and MRI scanning at the same time points to help discern whether study treatments induce brain changes toward or away from normal values. Primary study outcomes will include anatomical MRI, functional MRI, and Diffusion Tensor Imaging measures. Study hypotheses will be tested using the treatment-by-time interaction assessed in multiple general linear models with repeated measures analyses in an intent-to-treat analysis. DISCUSSION: MODE may allow the identification of brain-based biomarkers that may be more sensitive than traditional behavioral and clinical measures in discriminating, predicting, and mediating treatment response. These findings could help to personalize care for patients who have chronic depression patients and early life trauma, and they will provide new therapeutic targets for both psychological and biological treatments for major depressive illness.

Learning during sleep in humans - A historical review.

Sleep helps to consolidate previously acquired memories. Whether new information such as languages and other useful skills can also be learned during sleep has been debated for over a century, however, the sporadic studies' different objectives and varied methodologies make it difficult to draw definitive conclusions. This review provides a comprehensive overview of the history of sleep learning research conducted in humans, from its empirical beginnings in the 1940s to the present day. Synthesizing the findings from 51 research papers, we show that several studies support the notion that simpler forms of learning, such as habituation and conditioning, are possible during sleep. In contrast, the findings for more complex, applied learning (e.g., learning a new language during sleep) are more divergent. While there is often an indication of processing and learning during sleep when looking at neural markers, behavioral evidence for the transfer of new knowledge to wake remains inconclusive. We close by critically examining the limitations and assumptions that have contributed to the discrepancies in the literature and highlight promising new directions in the field.

Dissociating effects of aging and genetic risk of sporadic Alzheimer's disease on path integration.

Path integration is a spatial navigation ability that requires the integration of information derived from self-motion cues and stable landmarks, when available, to return to a previous location. Path integration declines with age and Alzheimer's disease (AD). Here, we sought to separate the effects of age and AD risk on path integration, with and without a landmark. Overall, 279 people participated, aged between 18 and 80 years old. Advanced age impaired the appropriate use of a landmark. Older participants furthermore remembered the location of the goal relative to their starting location and reproduced this initial view without considering that they had moved in the environment. This lack of adaptative behavior was not associated with AD risk. In contrast, participants at genetic risk of AD (apolipoprotein E ε4 carriers) exhibited a pure path integration deficit, corresponding to difficulty in performing path integration in the absence of a landmark. Our results show that advanced-age impacts landmark-supported path integration, and that this age effect is dissociable from the effects of AD risk impacting pure path integration.

Visual perspective in autobiographical memories of self-incongruent episodes.

It is widely assumed that autobiographical memory relies on an integration of episodic memory with the self-model. We hypothesise that self-memory integration depends critically on self-congruence. More specifically, self-incongruent experiences such as those that elicit shame or guilt may be more difficult to integrate. Self-incongruence may affect both the semantic reports of memories and their phenomenological characteristics, in particular their visual perspective (1PP or 3PP, i.e., field or observer perspective), their affective valence, and their perceived centrality. Diary based memories were assigned to 4 categories (shame, guilt, negative, neutral) and were rated for the different phenomenological dimensions. We used a deep neural network, univariate and multilevel models to assess differences and relationships between different variables. We found that memories that elicited shame (but not guilt) showed more pronounced 3PP as compared to other experiences. Shameful episodes also elicited the most pronounced negative affect. A multilevel analysis revealed that the amount of shame that an episode elicited, and its semantic similarity with shame episodes, predicted higher 3PP, while affective valence did not. Our results show that self-incongruence affects memories both at the level of their semantic reports and their phenomenology, and thus contributes to a mechanistic understanding of self-memory integration.

Acute stress impairs visual path integration.

Acute stress exerts substantial effects on episodic memory, which are often mediated by glucocorticoids, the end-product of the hypothalamic-pituitary-adrenal axis. Surprisingly little is known, however, about the influence of acute stress on human spatial navigation. One specific navigational strategy is path integration, which is linked to the medial entorhinal cortex, a region harboring glucocorticoid receptors and thus susceptible for stress effects. Here, we investigated effects of acute stress on path integration performance using a virtual homing task. We divided a sample of healthy young male participants into a stress group (nstress = 32) and a control group (ncontrol = 34). The stress group underwent the socially evaluated cold-pressor test, while the control group underwent a non-stressful control procedure. Stress induction was confirmed via physiological and subjective markers, including an increase of salivary cortisol concentrations. We applied linear mixed models to investigate the effect of acute stress on path integration depending on task difficulty and the presence or absence of spatial cues. These analyses revealed that stress impaired path integration especially in trials with high difficulty and led to greater decline of performance upon removal of spatial cues. Stress-induced deficits were strongly related to impaired distance estimation, and to a lesser extent to compromised rotation estimation. These behavioral findings are in accordance with the hypothesis that acute stress impairs path integration processes, potentially by affecting the entorhinal grid cell system. More generally, the current data suggests acute stress to impair cognitive functions mediated by medial temporal lobe regions outside the hippocampus.

Multi-scale goal distance representations in human hippocampus during virtual spatial navigation.

Goal-directed navigation relies on both coarse and fine-grained coding of spatial distance between the current position of a navigating subject and a goal destination. However, the neural signatures underlying goal distance coding remain poorly understood. Using intracranial EEG recordings from the hippocampus of drug-resistant epilepsy patients who performed a virtual spatial navigation task, we found that the right hippocampal theta power was significantly modulated by goal distance and decreased with goal proximity. This modulation varied along the hippocampal longitudinal axis such that theta power in the posterior hippocampus decreased more strongly with goal proximity. Similarly, neural timescale, reflecting the duration across which information can be maintained, increased gradually from the posterior to anterior hippocampus. Taken together, this study provides empirical evidence for multi-scale spatial representations of goal distance in the human hippocampus and links the hippocampal processing of spatial information to its intrinsic temporal dynamics.

Representational formats of human memory traces.

Neural representations are internal brain states that constitute the brain's model of the external world or some of its features. In the presence of sensory input, a representation may reflect various properties of this input. When perceptual information is no longer available, the brain can still activate representations of previously experienced episodes due to the formation of memory traces. In this review, we aim at characterizing the nature of neural memory representations and how they can be assessed with cognitive neuroscience methods, mainly focusing on neuroimaging. We discuss how multivariate analysis techniques such as representational similarity analysis (RSA) and deep neural networks (DNNs) can be leveraged to gain insights into the structure of neural representations and their different representational formats. We provide several examples of recent studies which demonstrate that we are able to not only measure memory representations using RSA but are also able to investigate their multiple formats using DNNs. We demonstrate that in addition to slow generalization during consolidation, memory representations are subject to semantization already during short-term memory, by revealing a shift from visual to semantic format. In addition to perceptual and conceptual formats, we describe the impact of affective evaluations as an additional dimension of episodic memories. Overall, these studies illustrate how the analysis of neural representations may help us gain a deeper understanding of the nature of human memory.

The influence of the behavioural inhibition system on the development of PTSD-like symptoms after presentation of a traumatic film in healthy subjects.

BACKGROUND: The Behavioural Inhibition System (BIS) as a neural system controlling motivation and behaviour, has previously been linked to multiple mental disorders, including Post-traumatic Stress Disorder (PTSD). BIS-sensitivity could increase the likelihood of PTSD development after trauma. However, previous studies have largely measured BIS-sensitivity retrospectively (i.e. after trauma, or even after onset of PTSD). OBJECTIVE: The study aims to confirm the relationship between BIS-sensitivity prior to trauma and PTSD symptoms. METHOD: After assessment of BIS-sensitivity, N = 119 healthy participants watched a film with visually disturbing material. After 72 h, participants completed a questionnaire on PTSD-related symptoms (PCL-5). RESULTS: In a multiple linear regression model, BIS-sensitivity significantly predicted PTSD symptoms, even after controlling for the decrease in mood, as well as for participants' age and sex, two factors that had previously been shown to influence BIS-sensitivity. CONCLUSIONS: This is the first study to measure BIS-sensitivity before the occurrence of the (experimental) trauma and strengthens its role as a potential pre-traumatic risk factor.

Main research question: What factors predict the development of posttraumatic symptoms after exposure to a traumatic event?The candidate investigated here is the Behavioral Inhibition System (BIS), a neural system controlling motivation and behavior. Our study provides evidence that the BIS is a potential risk factor, prediciting the development of posttraumatic symptoms after exposure to an experimental trauma in healthy participants.

Chronic stress is associated with specific path integration deficits.

Repeated exposure to stress (chronic stress) can cause excess levels of circulating cortisol and has detrimental influences on various cognitive functions including long-term memory and navigation. However, it remains an open question whether chronic stress affects path integration, a navigational strategy that presumably relies on the functioning of grid cells in the medial entorhinal cortex. The entorhinal cortex is a brain region in the medial temporal lobe, which contains multiple cell types involved in spatial navigation (and episodic memory), and a high number of corticosteroid receptors, predisposing it as a potential target of cortisol effects. Here, our goal was to investigate the association between chronic stress and path integration performance. We assessed chronic stress via hair cortisol concentration (physiological measure) and the Perceived Stress Questionnaire (subjective measure) in 52 female participants aged 22-65 years. Path integration was measured using a virtual homing task. Linear mixed models revealed selective impairments associated with chronic stress that depended on error type and environmental features. When focusing on distance estimations in the path integration task, we observed a significant relationship to hair cortisol concentrations indicating impaired path integration particularly during trials with higher difficulty in participants with high hair cortisol concentrations. This relationship especially emerged in the absence of spatial cues (a boundary or a landmark), and particularly in participants who reported high levels of subjectively experienced chronic stress. The findings are in line with the hypothesis that chronic stress compromises path integration, possibly via an effect on the entorhinal grid cell system.

Where was the toaster? A systematic investigation of semantic construction in a new virtual episodic memory paradigm.

Retrieved memories of past events are often inaccurate. The scenario construction model (SCM) postulates that during encoding, only the gist of an episode is stored in the episodic memory trace and during retrieval, information missing from that trace is constructed from semantic information. The current study aimed to find behavioural evidence for semantic construction in a realistic, yet controlled setting by introducing a completely new paradigm and adjusted memory tests that measure semantic construction. Using a desktop virtual reality (VR), participants navigated through a flat in which some household objects appeared in unexpected rooms, creating conflicts between the experienced episode and semantic expectations. The manipulation of congruence enabled us to identify influences from semantic information in cases of episodic memory failure during recall. Besides, we controlled for objects to be task-relevant or task-irrelevant to the sequence of action. In addition to an established old/new recognition task we introduced spatial and temporal recall measures as possible superior memory measures quantifying semantic construction. The recognition task and the spatial recall revealed that both congruence and task-relevance predicted correct episodic memory retrieval. In cases of episodic memory failure, semantic construction was more likely than guessing and occurred more frequently for task-irrelevant objects. In the temporal recall object-pairs belonging to the same semantic room-category were temporally clustered together compared with object-pairs from different semantic categories (at the second retrieval delay). Taken together, our findings support the predictions of the SCM. The new VR paradigm, including the new memory measures appears to be a promising tool for investigating semantic construction.

Direct electrical brain stimulation of human memory: lessons learnt and future perspectives.

Modulation of cognitive functions supporting human declarative memory is one of the grand challenges of neuroscience, and of vast importance for a variety of neuropsychiatric, neurodegenerative and neurodevelopmental diseases. Despite a recent surge of successful attempts at improving performance in a range of memory tasks, the optimal approaches and parameters for memory enhancement have yet to be determined. On a more fundamental level, it remains elusive as to how delivering electrical current in a given brain area leads to enhanced memory processing. Starting from the local and distal physiological effects on neural populations, the mechanisms of enhanced memory encoding, maintenance, consolidation or recall in response to direct electrical stimulation are only now being unravelled. With the advent of innovative neurotechnologies for concurrent recording and stimulation intracranially in the human brain, it becomes possible to study both acute and chronic effects of stimulation on memory performance and the underlying neural activities. In this review, we summarize the effects of various invasive stimulation approaches for modulating memory functions. We first outline the challenges that were faced in the initial studies of memory enhancement and the lessons learnt. Electrophysiological biomarkers are then reviewed as more objective measures of the stimulation effects than behavioural outcomes. Finally, we classify the various stimulation approaches into continuous and phasic modulation with an open or closed loop for responsive stimulation based on analysis of the recorded neural activities. Although the potential advantage of closed-loop responsive stimulation over the classic open-loop approaches is inconclusive, we foresee the emerging results from ongoing longitudinal studies and clinical trials will shed light on both the mechanisms and optimal strategies for improving declarative memory. Adaptive stimulation based on the biomarker analysis over extended periods of time is proposed as a future direction for obtaining lasting effects on memory functions. Chronic tracking and modulation of neural activities intracranially through adaptive stimulation opens tantalizing new avenues to continually monitor and treat memory and cognitive deficits in a range of brain disorders. Brain co-processors created with machine-learning tools and wireless bi-directional connectivity to seamlessly integrate implanted devices with smartphones and cloud computing are poised to enable real-time automated analysis of large data volumes and adaptively tune electrical stimulation based on electrophysiological biomarkers of behavioural states. Next-generation implantable devices for high-density recording and stimulation of electrophysiological activities, and technologies for distributed brain-computer interfaces are presented as selected future perspectives for modulating human memory and associated mental processes.

Representational dynamics of memories for real-life events.

The continuous flow of experience that characterizes real-life events is not recorded as such in episodic memory but is condensed as a succession of event segments separated by temporal discontinuities. To unravel the neural basis of this representational structure, we recorded real-life events using wearable camera technology and used fMRI to investigate brain activity during their temporal unfolding in memory. We found that, compared to the representation of static scenes in memory, dynamically unfolding memory representations were associated with greater activation of the posterior medial episodic network. Strikingly, by analyzing the autocorrelation of brain activity patterns at successive time points throughout the retrieval period, we found that this network showed higher temporal dynamics when recalling events that included a higher density of event segments. These results reveal the key role of the posterior medial network in representing the dynamic unfolding of the event segments that constitute real-world memories.

Aversive memory formation in humans involves an amygdala-hippocampus phase code.

Memory for aversive events is central to survival but can become maladaptive in psychiatric disorders. Memory enhancement for emotional events is thought to depend on amygdala modulation of hippocampal activity. However, the neural dynamics of amygdala-hippocampal communication during emotional memory encoding remain unknown. Using simultaneous intracranial recordings from both structures in human patients, here we show that successful emotional memory encoding depends on the amygdala theta phase to which hippocampal gamma activity and neuronal firing couple. The phase difference between subsequently remembered vs. not-remembered emotional stimuli translates to a time period that enables lagged coherence between amygdala and downstream hippocampal gamma. These results reveal a mechanism whereby amygdala theta phase coordinates transient amygdala -hippocampal gamma coherence to facilitate aversive memory encoding. Pacing of lagged gamma coherence via amygdala theta phase may represent a general mechanism through which the amygdala relays emotional content to distant brain regions to modulate other aspects of cognition, such as attention and decision-making.