Autonomic and cognitive control in memory: Investigating the psychophysiological link using heart rate variability biofeedback.

Vagally mediated heart rate variability (vmHRV) at resting state has been associated to cognitive functions dependent on cognitive control, such as memory. However, little is known about the phasic interaction between cognitive and autonomic control. In a pre-registered within-between-subject designed experiment, the potential of vmHRV biofeedback to simultaneously stimulate vmHRV during memory processing and cognitive control over long-term memory was tested, along with investigating psychophysiological association. 71 young healthy adults completed (twice) a false memory task in virtual reality. Immediately before memory encoding and retrieval, participants practiced either vmHRV biofeedback or a control breathing exercise. Cognitive control over long-term memory was assessed as the confidence toward false memories and the capability to discriminate them from true memories. Resting-state vmHRV before each test and phasic vmHRV during memory encoding and retrieval were measured as the root mean square differences (RMSSD) in the heart period. vmHRV biofeedback had neither an immediate effect on measures of cognitive control over long-term memory nor on phasic RMSSD. Moreover, neither resting-state nor phasic vmHRV correlated to the cognitive scores. Consequently, the utility of HRV biofeedback as a psychophysiological stimulation tool and a link between vmHRV and cognitive control over long-term memory could not be verified. Exploratory analyses revealed that baseline shift in parasympathetic activity confounded the psychophysiological association. Future directions are provided that could shed light on the relationship between cognition and vmHRV.

Reduction of alcohol use and increase in psychological flexibility after a naturalistic psychedelic experience: a retrospective survey.

INTRODUCTION: Alcohol use can be significantly associated with negative social, professional, and health outcomes. Even more so, alcohol use disorder (AUD) is a critical public health issue and major avoidable risk factor. This study aimed to examine the effect of a naturalistic psychedelic experience on alcohol use and related measures. METHODS: A retrospective online survey was conducted on 160 individuals who reported a psychedelic experience and a concomitant drinking habit but did not necessarily have an AUD. Demographic data, characteristics of the psychedelic experience, and changes in alcohol consumption and psychological flexibility were surveyed. Results: The mean number of drinking days per week and AUDIT scores significantly decreased after the psychedelic experience (P < .001). Subjects who quit or reduced drinking had a more severe AUD (P < .01) and lower psychological flexibility (P = .003) before the psychedelic session. Alcohol use reduction was significantly associated with the intensity of the mystical experience (P = .03). Psychological flexibility increased more in participants who reduced their alcohol use (P < .001), and the change in psychological flexibility was one of the predictors of alcohol use improvement (P = .003). Conclusion: Our findings suggest that a naturalistic psychedelic experience could be associated with a reduction in alcohol use and dependency. Such positive health outcomes can be associated with the intensity of the mystical experience as well as an increase in psychological flexibility.

Neurophysiological explorations across the spectrum of psychosis, autism, and depression, during wakefulness and sleep: protocol of a prospective case-control transdiagnostic multimodal study (DEMETER).

BACKGROUND: Quantitative electroencephalography (EEG) analysis offers the opportunity to study high-level cognitive processes across psychiatric disorders. In particular, EEG microstates translate the temporal dynamics of neuronal networks throughout the brain. Their alteration may reflect transdiagnostic anomalies in neurophysiological functions that are impaired in mood, psychosis, and autism spectrum disorders, such as sensorimotor integration, speech, sleep, and sense of self. The main questions this study aims to answer are as follows: 1) Are EEG microstate anomalies associated with clinical and functional prognosis, both in resting conditions and during sleep, across psychiatric disorders? 2) Are EEG microstate anomalies associated with differences in sensorimotor integration, speech, sense of self, and sleep? 3) Can the dynamic of EEG microstates be modulated by a non-drug intervention such as light hypnosis? METHODS: This prospective cohort will include a population of adolescents and young adults, aged 15 to 30 years old, with ultra-high-risk of psychosis (UHR), first-episode psychosis (FEP), schizophrenia (SCZ), autism spectrum disorder (ASD), and major depressive disorder (MDD), as well as healthy controls (CTRL) (N = 21 × 6), who will be assessed at baseline and after one year of follow-up. Participants will undergo deep phenotyping based on psychopathology, neuropsychological assessments, 64-channel EEG recordings, and biological sampling at the two timepoints. At baseline, the EEG recording will also be coupled to a sensorimotor task and a recording of the characteristics of their speech (prosody and turn-taking), a one-night polysomnography, a self-reference effect task in virtual reality (only in UHR, FEP, and CTRL). An interventional ancillary study will involve only healthy controls, in order to assess whether light hypnosis can modify the EEG microstate architecture in a direction opposite to what is seen in disease. DISCUSSION: This transdiagnostic longitudinal case-control study will provide a multimodal neurophysiological assessment of clinical dimensions (sensorimotor integration, speech, sleep, and sense of self) that are disrupted across mood, psychosis, and autism spectrum disorders. It will further test the relevance of EEG microstates as dimensional functional biomarkers. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT06045897.

Mindfulness and false memories: state and dispositional mindfulness does not increase false memories for naturalistic scenes presented in a virtual environment.

Mindfulness attracted increased research interests in the last decade, reporting an overall beneficial effect of this practice on cognitive performances. Nevertheless, recently a possible detrimental impact of mindfulness has been underlined. While the effect of mindfulness on memory remains under-explored, recent studies have observed an increased false-memory susceptibility after mindfulness practice. A possible explanatory mechanism has been suggested, related to the nature of the studied material. For semantically related information, mindfulness would increase false memories; however, the addition of rich perceptual information could prevent this detrimental effect. The present study aimed to verify this hypothesis by testing the impact of state mindfulness induced by a short meditation session, and dispositional mindfulness on the production of false memory for pictorial material presented in a complex virtual environment. We employed a virtual reality version of the Deese-Roediger-McDermott paradigm (DRM), a classical protocol to induce false memories. Contrary to previous studies, we did not observe any effect of mindfulness on false or correct memories (free recall and recognition) after a short mindfulness practice session compared to a control condition. Nonetheless, we found a beneficial effect of mindfulness practice on memory sensitivity. Additionally, we reported a positive and negative effect of dispositional mindfulness on memory outcomes. While the Non-Reactivity facet was associated with overall better memory performances, we observed an association between the Acting with Awareness facet and an increased recollection of lures. We discuss these findings in line with a recent proposal on the link between mindfulness and episodic memory.

How rich are false memories in a naturalistic context in healthy aging?

The recall of factual and contextual information is a core characteristic of episodic memory sensitive to aging effects. The innovative aim of the present study was to assess in a naturalistic context the quantity and quality of correct and false free recalls among younger and older adults considering feature binding (What-Where-When-Details) and recollection (Remembering vs. Knowing). Thanks to virtual reality, we designed a multimodal environment simulating a lively town in which we implemented a variant of a DRM task rich in sets of semantically related items (e.g., fruits on a market stall). We asked 30 young and 30 older participants to navigate in the virtual environment, paying attention to the items, and then recall as many items and as much contextual information as possible and indicate the presence of recollection. As expected, older adults produced fewer correct recall but more intrusions than younger adults, and their correct recall was more deficient in binding and recollection. In both age groups, false recall was associated with the correct context inferred from a related set of items. However, the intrusions produced by older adults were highly recollected compared to those of the younger adults, and they were associated with false item-related contextual information.

Gender identity better than sex explains individual differences in episodic and semantic components of autobiographical memory: An fMRI study.

Advances in the literature of sex-related differences in autobiographical memory increasingly tend to highlight the importance of psychosocial factors such as gender identity, which may explain these differences better than sex as a biological factor. To date, however, none of these behavioral studies have investigated this hypothesis using neuroimaging. The purpose of this fMRI study is to examine for the first time sex and gender identity-related differences in episodic and semantic autobiographical memory in healthy participants (M=19, W=18). No sex-related differences were found; however, sex-related effects of masculine and feminine gender identity were identified in men and women independently. These results confirm the hypothesis that differences in episodic and semantic autobiographical memory are best explained by gender but are an interaction between biological sex and gender identity and extend these findings to the field of neuroimaging. We discuss the importance of hormonal factors to be taken into consideration in the future.

The production of false recognition and the associated state of consciousness following encoding in a naturalistic context in aging.

Using virtual reality, we implemented a naturalistic variant of the DRM paradigm in young and older adults to evaluate false recall and false recognition. We distinguished false recognition related to the highest semantic association (the critical lures), semantic similarity (i.e. items that belong to the same semantic category), and perceptual similarity (i.e. items that are similar, but not identical in terms of shape or color). The data revealed that younger adults recalled and recognized more correct elements than older adults did while the older adults intruded more critical items than younger adults. Both age groups produced false recognition related to the critical items, followed by perceptually and then semantically related items. False recognitions were highly recollective as they were mainly associated with a sense of remembering, even more so in older adults than in young adults. The decline of executive functions and working memory predicted age-related increases in false memories.

In Medio Stat Virtus: intermediate levels of mind wandering improve episodic memory encoding in a virtual environment.

Episodic memory encoding is highly influenced by the availability of attentional resources. Mind wandering corresponds to a shift of attention toward task-unrelated thoughts. Few studies, however, have tested this link between memory encoding and mind wandering. The goal of the present work was to systematically investigate the influence of mind wandering during encoding on episodic memory performances in an ecological setting. Fifty-two participants were asked to navigate in a virtual urban environment. During the walk, they encountered different scenes that, unbeknownst to the participants, were target items presented in a subsequent recognition task associated with a Remember-Know-Guess paradigm. Each item triggered, after a random interval, a thought probe assessing current mind wandering. We found a significant linear positive relationship between the ratio of correctly recognized items and the overall mind wandering reported after the task. Moreover, we found a quadratic reversed U-shaped relationship between the probability of giving a 'Remember' response and both on-line and mind wandering reported a posteriori. The nearer to the medium value the level of mind wandering was, the higher was the probability to have a recollection-based recognition. Our results indicate that in a complex environment, the highest probability of actually remembering a scene would be when participants present a medium attentional level: neither distracted by inner thoughts nor too focused on the environment. This open attentional state would allow a better global processing of the environment by preventing one's attention from being captured by internal thoughts or narrowed by an over-focusing on the environment.

"Walk this way": specific contributions of active walking to the encoding of metric properties during spatial learning.

The effect of body-based information on spatial memory has been traditionally described as a facilitating factor for large-scale spatial learning in the field of active learning research (Chrastil & Warren, Psychonomic Bulletin and Review, 19(1):1-23; 2012). The specific contribution of body-based information to spatial representation properties is however not yet well defined and the mechanisms through which body-based information contributes to spatial learning are not clear enough. To disambiguate the effect of active spatial learning on the quality of spatial representations from the beneficial effect of physiological arousal, we compared four experimental conditions (walking on a unidirectional treadmill during learning, retrieval, both phases or no walking). Results showed no effect of the walking condition for a route perspective task, but a significant effect on a survey perspective task (landmark positioning on a map): participants who walked during encoding (encoding group and encoding + retrieval group) obtained better results than those who did not walk or walked only during retrieval. Geometrical analysis of spatial positions on maps revealed that the activity of walking during encoding improves the correlation between participants' coordinates and actual coordinates through better distance estimations and angular accuracy, even though the optic flow was not matched with individual walking speed. Control group variance in all measures was higher than that of the walking groups (regardless of the moment of walking). Taken together, these results provide arguments for the multimodal nature of spatial representations, where body-related information derived from walking is involved in metric properties accuracy and perspective switching.

The role of semantic memory in prospective memory and episodic future thinking: new insights from a case of semantic dementia.

Prospective memory (PM), the ability to remember to execute planned actions, and episodic future thinking (EFT), the ability to imagine future personal events, are two core aspects of future-oriented cognition. The present study aimed for the first time at examining the role of semantic memory loss in PM and EFT in a single case patient (SL) at the early stage of semantic dementia.First, we investigated various types of PM as well as episodic memory of new events using a validated ecological assessment via virtual reality. Second, we examined EFT using a temporally extended version of the TEMPau task, which measures episodic aspects of remembering the past and imagining the future taking temporal distance into account.Patient SL was deficient in semantically linked event-based PM and was unable to provide any EFT for the most distant period but was preserved in other types of PM and near and intermediate EFT.These findings provide new evidence on the role of semantic memory in PM depending on the type of intention and in EFT depending on the temporal distance mirroring autobiographical memory. Finally, they point out a specific link between PM and near EFT in future-oriented cognition.

The impact of state and dispositional mindfulness on prospective memory: A virtual reality study.

Prospective memory (PM) consists of remembering to perform an action that was previously planned. The recovery and execution of these actions require attentional resources. Mindfulness, as a state or a dispositional trait, has been associated with better attentional abilities while mind wandering is linked with attentional failures. In this study, we investigated the impact of mindfulness on PM. Eighty participants learned 15 cue-action associations. They were, then, asked to recall the actions at certain moments (time-based items) or places (event-based items) during a walk in a virtual town. Before the PM task, participants were randomly assigned to a mindfulness or mind wandering (control condition) session. Dispositional mindfulness was measured via the Five Facets Mindfulness Questionnaire (FFMQ). Although considered as two opposite states, we did not report any difference between the two groups on PM abilities. Nevertheless, the natural tendency to describe one's own sensations (the Describing facet of the FFMQ) predicted time-based performance in both groups. We discuss different hypotheses to explain this finding in light of recent findings on the impact of mind wandering on future oriented cognition. Our main observation is a positive link between the Describing facet and time-based PM performances. We propose that this link could be due to the common association of this mindfulness facets and PM with attentional and interoceptive abilities. Additional studies are needed to explore this hypothesis.

Phenomenal, bodily and brain correlates of fictional reappraisal as an implicit emotion regulation strategy.

The ability to modulate our emotional experience, depending on our current goal and context, is of critical importance for adaptive behavior. This ability encompasses various emotion regulation strategies, such as fictional reappraisal, at stake whenever one engages in fictional works (e.g., movies, books, video games, virtual environments). Neuroscientific studies investigating the distinction between the processing of real and fictional entities have reported the involvement of brain structures related to self-relevance and emotion regulation, suggesting a threefold interaction between the appraisal of reality, aspects of the Self, and emotions. The main aim of this study is to investigate the effect of implicit fictional reappraisal on different components of emotion, as well as on the modulatory role of autobiographical and conceptual self-relevance. While recording electrodermal, cardiac, and brain activity (EEG), we presented negative and neutral pictures to 33 participants, describing them as either real or fictional. After each stimulus, the participants reported their subjective emotional experience, self-relevance of the stimuli, as well as their agreement with their description. Using the Bayesian mixed-modeling framework, we showed that stimuli presented as fictional, compared with real, were subjectively appraised as less intense and less negative, and elicited lower skin conductance response, stronger heart-rate deceleration, and lower late positive potential amplitudes. Finally, these phenomenal and physiological changes did, to a moderate extent, rely on variations of specific aspects of self-relevance. Implications for the neuroscientific study of implicit emotion regulation are discussed.

Dispositional mindfulness attenuates the emotional attentional blink.

Emotional stimuli have been shown to automatically hijack attention, hindering the detection of forthcoming targets. Mindfulness is defined as a present moment non-judgemental attentional stance that can be cultivated by meditation practices, but that may present interindividual variability in the general population. The mechanisms underlying modification in emotional reactivity linked to mindfulness are still a matter of debate. In particular, it is not clear whether mindfulness is associated with a diminished emotional response, or with faster recovery. We presented participants with target pictures embedded in a rapid visual presentation stream. The targets could be preceded by negative, neutral or scrambled critical distractors. We showed that dispositional mindfulness, in particular the Non-reacting facet, was related to faster disengagement of attention from emotional stimuli. These results could have implications for mood disorders characterised by an exaggerated attentional bias toward emotional stimuli, such as anxiety and post-traumatic stress disorders.

Gender identity better than sex explains individual differences in episodic and semantic components of autobiographical memory and future thinking.

A recently tested hypothesis suggests that inter-individual differences in episodic autobiographical memory (EAM) are better explained by individual identification of typical features of a gender identity than by sex. This study aimed to test this hypothesis by investigating sex and gender related differences not only in EAM but also during retrieval of more abstract self-knowledge (i.e., semantic autobiographical memory, SAM, and conceptual self, CS), and considering past and future perspectives. No sex-related differences were identified, but regardless of the sex, feminine gender identity was associated with clear differences in emotional aspects that were expressed in both episodic and more abstract forms of AM, and in the past and future perspectives, while masculine gender identity was associated with limited effects. In conclusion, our results support the hypothesis that inter-individual differences in AM are better explained by gender identity than by sex, extending this assumption to both episodic and semantic forms of AM and future thinking.

Interaction between attentional systems and episodic memory encoding: the impact of conflict on binding of information.

Episodic memory (EM) is defined as a long-term memory system that stores information that can be retrieved along with details of the context of the original events (binding). Several studies have shown that manipulation of attention during encoding can impact subsequent memory performance. An influential model of attention distinguishes between three partially independent attentional networks: the alerting, the orienting and the executive or conflict resolution component. To date, the impact of the engagement of these sub-systems during encoding on item and relational context binding has not been investigated. Here, we developed a new task combining the Attentional Network Test and an incidental episodic memory encoding task to study this issue. We reported that when the alerting network was not solicited, resolving conflict hindered item encoding. Moreover, resolving conflict, independently of the cueing condition, had a negative impact on context binding. These novel findings could have a potential impact in the understanding EM formation, and memory disorders in different populations, including healthy elderly people.

"Being there" and remembering it: Presence improves memory encoding.

Few studies have investigated the link between episodic memory and presence: the feeling of "being there" and reacting to a stimulus as if it were real. We collected data from 244 participants after they had watched the movie Avengers: Age of Ultron. They answered questions about factual (details of the movie) and temporal memory (order of the scenes) about the movie, as well as their emotion experience and their sense of presence during the projection. Both higher emotion experience and sense of presence were related to better factual memory, but not to temporal order memory. Crucially, the link between emotion and factual memory was mediated by the sense of presence. We interpreted the role of presence as an external absorption of the attentional focus toward the stimulus, thus enhancing memory encoding. Our findings could shed light on the cognitive processes underlying memory impairments in psychiatric conditions characterized by an altered sense of reality.

Aging Stereotypes Must be Taken Into Account for the Diagnosis of Prodromal and Early Alzheimer Disease.

Because of a dramatic increase of older people worldwide, screening for prodromal state of Alzheimer disease (AD) is a major societal challenge. Many individuals diagnosed with prodromal AD, do not convert to AD, some remaining stable and others reversing back to normal. We argue that an important source of this overdiagnosis comes from negative aging stereotypes (eg, the culturally shared beliefs that aging inescapably causes severe cognitive decline and diseases). Many laboratory studies show that such stereotypes impair memory performance in healthy older adults, producing inflated age differences. Research is needed to examine how aging stereotypes implicitly permeate neuropsychological testing and contribute to false positives.

Self-reference recollection effect and its relation to theory of mind: An investigation in healthy controls and schizophrenia.

This study explores the links between the Self-Reference Effect (SRE) and Theory of Mind (ToM) in typical adults and patients with schizophrenia. Participants were assessed with a self-referential memory paradigm investigating the mnemonic effect of both semantic and episodic self-reference with a recognition task associated with the Remember/Know/Guess paradigm. They also completed a self-descriptive scale and shortened versions of the attribution of intention task and the reading the mind in the eyes test as measures of cognitive and affective ToM respectively. Unlike typical adults, the patients showed no semantic SRRE (correct recognition associated with remembering), and there was no episodic SRRE and no SRE (on the number of correct recognitions) in either group. Semantic SRRE was correlated with the affective ToM in patients and with the positivity of the self-concept in the healthy group. We discuss that patients and typical adults use different strategies during self and other-reflection.

Impaired capacity for prospection in the dementias--Theoretical and clinical implications.

OBJECTIVES: Prospection, or future thinking, refers to the ability to mentally simulate plausible events at a future point in time and draws heavily upon the capacity to retrieve autobiographical details from the past. This review examines the extent to which prospection is compromised in neurodegenerative disorders with a view to identifying (1) underlying mechanisms of future thinking disruption and (2) the impact of future thinking deficits on everyday adaptive functioning. METHODS: PubMed and MEDLINE were searched for peer-reviewed articles published or in press up to 14 October 2014. The key criterion for inclusion was that the primary outcome measure concerned the envisaging of episodic events at a future time point. Search terms of 'future thinking', 'prospection', and 'future simulation' were used in combination with the following terms: 'dementia', 'Mild Cognitive Impairment', 'Alzheimer's disease', 'semantic dementia', 'frontotemporal dementia', 'Parkinson's disease', 'Motor Neuron disease', 'Vascular dementia', and 'Dementia with Lewy bodies' (e.g., 'future thinking' AND 'Alzheimer's disease'). Searches were limited to articles published in English. RESULTS: A total of nine unique papers were identified in which prospection was the main outcome measure in dementia. Collectively, these studies reveal marked impairments in the ability to simulate personally relevant events at a future time point in dementia syndromes. CONCLUSIONS: Future research investigating the real-world implications of prospection deficits in dementia is crucial to elucidate the interplay between future-oriented thought and everyday adaptive functions such as prospective memory, decision-making, and maintaining a coherent sense of self over time.