Neural substrates of the self-memory system: new insights from a meta-analysis

Cortical hubs of highly superior autobiographical memory

Highly Superior Autobiographical Memory (HSAM) is a rare form of enhanced memory in which individuals demonstrate an extraordinary ability to remember details of their personal lives with high levels of accuracy and vividness. Neuroimaging studies have identified brain regions - specifically, midline areas within the default network - associated with remembering events from one's past. Extending this research on the neural underpinnings of autobiographical memory, the present study utilizes graph theory analyses to compare functional brain connectivity in a cohort of HSAM (n = 12) and control participants (n = 29). We perform seed-based analysis in resting-state fMRI data to assess how specific cortical regions within the autobiographical memory network are differentially connected in HSAM individuals. Additionally, we apply a whole-brain connectivity analysis to identify differences in brain hub-network topology associated with enhanced autobiographical memory. Seed-based results show converging patterns of increased connectivity in HSAM across midline areas. Whole-brain analysis also reveals enhanced connectivity across medial prefrontal and posterior cingulate cortex in HSAM individuals. Together, these results extend prior research, highlighting cortical hubs within the default network associated with enhanced autobiographical memory.

Effects of past and future autobiographical thinking on the working self-concept

While the role of autobiographical memory in self-representation is well established, the identity function of future thinking has received much less attention. Yet, most people commonly imagine future events that convey meaningful information about the person they wish or expect to become. In three experiments, we assessed the extent to which thinking about such self-defining future events influences the current content of self-representation (i.e., the working self-concept). Participants were asked to think about either a past or future self-defining event, or a control topic, before describing aspects of their identity in the form of "I am" statements (Experiments 1 and 3) or completing scales assessing self-related dimensions (Experiments 2 and 3). We found that thinking about a future self-defining event led participants to conceptualise themselves more in terms of their psychological traits, as did thinking about a past self-defining event. Furthermore, thinking about a future self-defining event increased the sense of present-future self-continuity, whereas thinking about a past self-defining event increased the sense of past-present self-continuity. These results suggest that self-representations are fuelled not only by autobiographical memories, but also by projections into the future.

Sex differences in neural response to an acute stressor in individuals with an alcohol use disorder

BACKGROUND

Alcohol use disorder (AUD) and stress influence overlapping neural circuits in the brain. The literature is mixed regarding the presence of sex differences in the neural response to acute stressors, and this issue has not been examined in individuals with AUD. We validated a stress functional magnetic resonance imaging (fMRI) paradigm in individuals with AUD and tested for sex differences.

METHODS

Twenty-five treatment-seeking individuals with AUD (15M/10F) were recruited to participate in the neuroimaging study linked to a clinical trial of ibudilast (NCT03594435). To assess social-evaluative stress, participants completed the Montreal Imaging Stress Task (MIST). Whole brain and amygdala region-of-interest analyses were conducted. Subjective ratings of anxiety and distress were collected. Repeated measures ANCOVAs were performed to evaluate the effect of stress on anxiety and distress and to evaluate sex differences.

RESULTS

There were trend-level effects of stress on anxiety ratings and amygdala activation (p's = 0.06). There was a significant effect of stress in the bilateral thalamus, ventral tegmental area, and paracingulate (Z's > 4.09, p's < 0.03). There was a trend-level effect of sex on subjective ratings of stress (p's = 0.07). Females had higher amygdala activation in response to stress (p = 0.02). Females also had greater activation than males in the precuneus, posterior cingulate cortex, and right inferior frontal gyrus during acute stress (Z's > 3.56, p's < 0.03).

CONCLUSIONS

This study provides an initial validation of the MIST in a sample of individuals with AUD. It also provides preliminary evidence of sex differences in the response to social-evaluative stress, which is important, given the relevance of stress and negative emotionality as motivators for alcohol use in females.

The Evolution of the Optimization of Cognitive and Social Functions in the Cerebellum and Thereby the Rise of Homo sapiens Through Cumulative Culture

The evolution of the prominent role of the cerebellum in the development of composite tools, and cumulative culture, leading to the rise of Homo sapiens is examined. Following Stout and Hecht's (2017) detailed description of stone-tool making, eight key repetitive involvements of the cerebellum are highlighted. These key cerebellar learning involvements include the following: (1) optimization of cognitive-social control, (2) prediction (3) focus of attention, (4) automaticity of smoothness, appropriateness, and speed of movement and cognition, (5) refined movement and social cognition, (6) learns models of extended practice, (7) learns models of Theory of Mind (ToM) of teachers, (8) is predominant in acquisition of novel behavior and cognition that accrues from the blending of cerebellar models sent to conscious working memory in the cerebral cortex. Within this context, the evolution of generalization and blending of cerebellar internal models toward optimization of social-cognitive learning is described. It is concluded that (1) repetition of movement and social cognition involving the optimization of internal models in the cerebellum during stone-tool making was the key selection factor toward social-cognitive and technological advancement, (2) observational learning during stone-tool making was the basis for both technological and social-cognitive evolution and, through an optimizing positive feedback loop between the cerebellum and cerebral cortex, the development of cumulative culture occurred, and (3) the generalization and blending of cerebellar internal models related to the unconscious forward control of the optimization of imagined future states in working memory was the most important brain adaptation leading to intertwined advances in stone-tool technology, cognitive-social processes behind cumulative culture (including the emergence of language and art) and, thereby, with the rise of Homo sapiens.

Intracranial Recordings of the Human Orbitofrontal Cortical Activity during Self-Referential Episodic and Valenced Self-Judgments

We recorded directly from the orbital (oPFC) and ventromedial (vmPFC) subregions of the orbitofrontal cortex (OFC) in 22 (9 female, 13 male) epilepsy patients undergoing intracranial electroencephalography (iEEG) monitoring during an experimental task in which the participants judged the accuracy of self-referential autobiographical statements as well as valenced self-judgments (SJs). We found significantly increased high-frequency activity (HFA) in ∼13% of oPFC sites (10/18 subjects) and 16% of vmPFC sites (4/12 subjects) during both of these self-referential thought processes, with the HFA power being modulated by the content of self-referential stimuli. The location of these activated sites corresponded with the location of fMRI-identified limbic network. Furthermore, the onset of HFA in the vmPFC was significantly earlier than that in the oPFC in all patients with simultaneous recordings in both regions. In 11 patients with available depression scores from comprehensive neuropsychological assessments, we documented diminished HFA in the OFC during positive SJ trials among individuals with higher depression scores; responses during negative SJ trials were not related to the patients' depression scores. Our findings provide new temporal and anatomical information about the mode of engagement in two important subregions of the OFC during autobiographical memory and SJ conditions. Our findings from the OFC support the hypothesis that diminished brain activity during positive self-evaluations, rather than heightened activity during negative self-evaluations, plays a key role in the pathophysiology of depression.

A theory of the neural mechanisms underlying negative cognitive bias in major depression

The widely acknowledged cognitive theory of depression, developed by Aaron Beck, focused on biased information processing that emphasizes the negative aspects of affective and conceptual information. Current attempts to discover the neurological mechanism underlying such cognitive and affective bias have successfully identified various brain regions associated with severally biased functions such as emotion, attention, rumination, and inhibition control. However, the neurobiological mechanisms of how individuals in depression develop this selective processing toward negative is still under question. This paper introduces a neurological framework centered around the frontal-limbic circuit, specifically analyzing and synthesizing the activity and functional connectivity within the amygdala, hippocampus, and medial prefrontal cortex. Firstly, a possible explanation of how the positive feedback loop contributes to the persistent hyperactivity of the amygdala in depression at an automatic level is established. Building upon this, two hypotheses are presented: hypothesis 1 revolves around the bidirectional amygdalohippocampal projection facilitating the amplification of negative emotions and memories while concurrently contributing to the impediment of the retrieval of opposing information in the hippocampus attractor network. Hypothesis 2 highlights the involvement of the ventromedial prefrontal cortex in the establishment of a negative cognitive framework through the generalization of conceptual and emotional information in conjunction with the amygdala and hippocampus. The primary objective of this study is to improve and complement existing pathological models of depression, pushing the frontiers of current understanding in neuroscience of affective disorders, and eventually contributing to successful recovery from the debilitating affective disorders.

The formation of episodic autobiographical memory is predicted by mental imagery, self-reference, and anticipated details

Introduction

Despite the ecological nature of episodic memory (EM) and the importance of consolidation in its functioning, studies tackling both subjects are still scarce. Therefore, the present study aims at establishing predictions of the future of newly encoded information in EM in an ecological paradigm.

Methods

Participants recorded two personal events per day with a SenseCam portable camera, for 10 days, and characterized the events with different subjective scales (emotional valence and intensity, self-concept and self-relevance, perspective and anticipated details at a month, mental images…). They then performed a surprise free recall at 5 days and 1 month after encoding. Machine learning algorithms were used to predict the future of events (episodic or forgotten) in memory at 1 month.

Results

The best algorithm showed an accuracy of 78%, suggesting that such a prediction is reliably possible. Variables that best differentiated between episodic and forgotten memories at 1 month were mental imagery, self-reference, and prospection (anticipated details) at encoding and the first free recall.

Discussion

These results may establish the basis for the development of episodic autobiographical memory during daily experiences.

Brain connectivity patterns associated with individual differences in the access to experience-near personal semantics: a resting-state fMRI study

It has been proposed that a continuum of specificity exists between episodic and semantic autobiographical memory. Personal semantics have been theorized to situate intermediately on this continuum, with more "experience-near" personal semantics (enPS) closer to the episodic end. We used individual differences in behavior as a model to investigate brain networks associated with the access to episodic autobiographical (EAM) and enPS information, assessing the relation between performance in the EAM and enPS conditions of the Autobiographical Fluency Task (AFT) and intrinsic brain connectivity. Results of an intrinsic connectivity contrast analysis showed that the global connectivity of two clusters in the left and right posterior cingulate cortex (PCC) was predicted by performance in the enPS conditions. Moreover, enPS scores predicted the connectivity strength of the right PCC with the bilateral anterior hippocampus (aHC), anterior middle temporal gyrus (aMTG) and medial orbitofrontal cortex, and the left aMTG and PCC. enPS scores also predicted the connectivity strength of the left PCC with the bilateral HC and MTG. The network highlighted involves parts of the core and of the dorsal medial subsystems of the Default Mode Network, in line with the proposal that enPS represents an intermediate entity between episodic and semantic memory.

Neural substrates of specific and general autobiographical memory retrieval in younger and older adults

Healthy aging is associated with a shift away from the retrieval of specific episodic autobiographical memories (AMs), towards more general and semanticized memories. Younger adults modulate activity in the default mode network according to the episodic specificity of AM retrieval. However, little is known about whether aging disrupts this neural modulation. In the current study we examine age-related changes in the modulation of whole-brain networks in response to three tasks falling along a gradient of episodic specificity. Younger and older adults retrieved specific (unique) AMs, general (routine) AMs, and semantic (general knowledge) memories. We found that both younger and older adults modulated default mode regions in response to varying episodic specificity. In addition, younger adults upregulated activity in several default mode regions with increasing episodic specificity, while older adults either did not modulate these regions, or downregulated activity in these regions. In contrast, older adults upregulated activity in the left temporal pole for tasks with higher episodic specificity. These brain activation patterns converge with prior findings that specific AMs are diminished in episodic richness with age, but are supplemented with conceptual and general information. Age-related reductions in the modulation of default mode regions might contribute to the shift away from episodic retrieval and towards semantic retrieval, resulting in reduced episodic specificity of personal memories.

Evidence of Impaired Remote Experience-near Semantic Memory in Medial Temporal Lobe Amnesia

Neuropsychological research suggests that "experience-near" semantic memory, meaning knowledge attached to a spatiotemporal or event context, is commonly impaired in individuals who have medial temporal lobe amnesia. It is not known if this impairment extends to remotely acquired experience-near knowledge, which is a question relevant to understanding hippocampal/medial temporal lobe functioning. In the present study, we administered a novel semantic memory task designed to target knowledge associated with remote, "dormant" concepts, in addition to knowledge associated with active concepts, to four individuals with medial temporal lobe amnesia and eight matched controls. We found that the individuals with medial temporal lobe amnesia generated significantly fewer experience-near semantic memories for both remote concepts and active concepts. In comparison, the generation of abstract or "experience-far" knowledge was largely spared in the individuals with medial temporal lobe amnesia, regardless of whether the targets for retrieval were remote or active concepts. We interpret these findings as evidence that the medial temporal lobes may have a sustained role in the retrieval of semantic memories associated with spatiotemporal and event contexts, which are cognitive features often ascribed to episodic memory. These results align with recent theoretical models proposing that the hippocampus/medial temporal lobes support cognitive processes that are involved in, but not exclusive to, episodic memory.

The shared and unique neural correlates of personal semantic, general semantic, and episodic memory

One of the most common distinctions in long-term memory is that between semantic (i.e., general world knowledge) and episodic (i.e., recollection of contextually specific events from one's past). However, emerging cognitive neuroscience data suggest a surprisingly large overlap between the neural correlates of semantic and episodic memory. Moreover, personal semantic memories (i.e., knowledge about the self and one's life) have been studied little and do not easily fit into the standard semantic-episodic dichotomy. Here, we used fMRI to record brain activity while 48 participants verified statements concerning general facts, autobiographical facts, repeated events, and unique events. In multivariate analysis, all four types of memory involved activity within a common network bilaterally (e.g., frontal pole, paracingulate gyrus, medial frontal cortex, middle/superior temporal gyrus, precuneus, posterior cingulate, angular gyrus) and some areas of the medial temporal lobe. Yet the four memory types differentially engaged this network, increasing in activity from general to autobiographical facts, from autobiographical facts to repeated events, and from repeated to unique events. Our data are compatible with a component process model, in which declarative memory types rely on different weightings of the same elementary processes, such as perceptual imagery, spatial features, and self-reflection.

Who am I really? The ephemerality of the self-schema following vmPFC damage

We studied the role of the ventromedial prefrontal cortex (vmPFC) in supporting the self-schema, by asking vmPFC patients, along with healthy and brain-damaged controls, to judge the degree to which they (or another person) were likely to engage in a series of activities, and how confident they were in their responses. Critically, participants provided their judgments on two separate occasions, a week apart. Our underlying assumption was that a strong self-schema would lead to confident and stable self-related judgments. We observed that control groups exhibited higher across-session consistency for self-related compared to other-related judgments, while this self-advantage was absent in vmPFC patients. In addition, regression analyses showed that in control groups the level of confidence associated with a specific (self- or other-related) judgment predicted the stability of that judgment across sessions. In contrast, vmPFC patients' confidence and rating consistency were aligned only for other-related judgments. By contrast, self-related judgments changed across sessions regardless of the confidence level with which they were initially endorsed. These findings indicate that the vmPFC is crucial to maintaining the self-schema and supporting the reliable retrieval of self-related information.

Functional brain plasticity following childhood maltreatment: A longitudinal fMRI investigation of autobiographical memory processing

Altered autobiographical memory (ABM) processing characterizes some individuals with experiences of childhood maltreatment. This fMRI study of ABM processing evaluated potential developmental plasticity in neural functioning following maltreatment. Adolescents with (N = 19; MT group) and without (N = 18; Non-MT group) documented childhood maltreatment recalled specific ABMs in response to emotionally valenced cue words during fMRI at baseline (age 12.71 ± 1.48) and follow-up (14.88 ± 1.53 years). Psychological assessments were collected at both timepoints. Longitudinal analyses were carried out with BOLD signal changes during ABM recall and psychopathology to investigate change over time. In both groups there was relative stability of the ABM brain network, with some developmental maturational changes observed in cortical midline structures (ventromedial PFC (vmPFC), posterior cingulate cortex (pCC), and retrosplenial cortex (rSC). Significantly increased activation of the right rSC was observed only in the MT group, which was associated with improved psychological functioning. Baseline group differences in relation to hippocampal functioning, were not detected at follow-up. This study provides preliminary empirical evidence of functional developmental plasticity in children with documented maltreatment experience using fMRI. This suggests that altered patterns of brain function, associated with maltreatment experience, are not fixed and may reflect the potential to track a neural basis of resilience.

Episodic memory and personal semantics as triggers of nostalgia: its relationships between abstraction of memory content and temporal distance

Nostalgia, an autobiographically relevant positive emotion, is a sentimental longing or wistful affection for the past. Autobiographical memory, which is one of the cognitive bases of nostalgia, includes both abstract semantic and detailed episodic memories. Recent studies have defined and classified memories that are located between semantic and episodic memory as personal semantics. Although autobiographical memory and personal semantics range over a continuum, past nostalgia research has not focused on or controlled them. In two experiments, undergraduate students retrieved episodic memory and personal semantics and rated cognitive and affective items. The intensity of nostalgia differed according to the types of memory content and temporal distance of the memory from the present. These results revealed that not only unique events but also repeated events and autobiographical facts induced nostalgia; furthermore, repeated events from both the distant and recent past (primary and high school, respectively) consistently induced relatively greater nostalgia, but in some cases, they were not significantly different from other types of memory (i.e., unique events and autobiographical facts). These findings suggest that both episodic memory and personal semantics are involved in the occurrence of nostalgia.

Common and distinct correlates of construction and elaboration of episodic-autobiographical memory: An ALE meta-analysis

The recollection of episodic-autobiographical memories (EAMs) entails a complex temporal dynamic, from initial "construction" to subsequent "elaboration" of memories. While there is consensus that EAM retrieval involves a distributed network of brain regions, it is still largely debated which regions specifically contribute to EAM construction and/or elaboration. To clarify this issue, we conducted an Activation Likelihood Estimation (ALE) meta-analysis based on the Preferred Reporting Items for Systematic-Reviews and Meta-Analyses (PRISMA) method. We found common recruitment of the left hippocampus and posterior cingulate cortex (PCC) during both phases. Additionally, EAM construction led to activations in the ventromedial prefrontal cortex, left angular gyrus (AG), right hippocampus, and precuneus, while the right inferior frontal gyrus was activated by EAM elaboration. Although most of these regions are distributed over the default mode network, the current findings highlight a differential contribution according to early (midline regions, left/right hippocampus, and left AG) versus later (left hippocampus, and PCC) recollection. Overall, these findings contribute to clarify the neural correlates that support the temporal dynamics of EAM recollection.

Me, Myself and My Insula: An Oasis in the Forefront of Self-Consciousness

The insula is a multiconnected brain region that centralizes a wide range of information, from the most internal bodily states, such as interoception, to high-order processes, such as knowledge about oneself. Therefore, the insula would be a core region involved in the self networks. Over the past decades, the question of the self has been extensively explored, highlighting differences in the descriptions of the various components but also similarities in the global structure of the self. Indeed, most of the researchers consider that the self comprises a phenomenological part and a conceptual part, in the present moment or extending over time. However, the anatomical substrates of the self, and more specifically the link between the insula and the self, remain unclear. We conducted a narrative review to better understand the relationship between the insula and the self and how anatomical and functional damages to the insular cortex can impact the self in various conditions. Our work revealed that the insula is involved in the most primitive levels of the present self and could consequently impact the self extended in time, namely autobiographical memory. Across different pathologies, we propose that insular damage could engender a global collapse of the self.

Connectivity Profile of Middle Inferior Parietal Cortex Confirms the Hypothesis About Modulating Cortical Areas

According to the correlated transmitter-receptor based structure of the inferior parietal cortex (IPC), this brain area is divided into three clusters, namely, the caudal, the middle and the rostral. Nevertheless, in associating different cognitive functions to the IPC, previous studies considered this part of the cortex as a whole and thus inconsistent results have been reported. Using multiband EPI, we investigated the connectivity profile of the middle IPC while forty-five participants performed a task requiring cognitive control. The middle IPC demonstrated functional associations which do not have similarities to a contributing part in the frontoparietal network, in processing cognitive control. At the same time, this cortical area showed negative functional connectivity with both the precuneus cortex, which is resting- state related, and brain areas related to general cognitive functions. That is, the functions of the middle IPC are not accommodated by the traditional categorization of different brain areas i.e. resting state-related or task-related networks and this advanced our hypothesis about modulating cortical areas. Such brain areas are characterized by their negative functional connectivity with parts of the cortex involved in task performance, proportional to the difficulty of the task; yet, their functional associations are inconsistent with the resting state-related cortical areas.

Word-producing brain: Contribution of the left anterior middle temporal gyrus to word production patterns in spoken language

Vocabulary is based on semantic knowledge. The anterior temporal lobe (ATL) has been considered an essential region for processing semantic knowledge; nonetheless, the association between word production patterns and the structural and functional characteristics of the ATL remains unclear. To examine this, we analyzed over one million words from group conversations among community-dwelling older adults and their multimodal magnetic resonance imaging data. A quantitative index for the word production patterns, namely the exponent β of Heaps' law, positively correlated with the left anterior middle temporal gyrus volume. Moreover, β negatively correlated with its resting-state functional connectivity with the precuneus. There was no significant correlation with the diffusion tensor imaging metrics in any fiber. These findings suggest that the vocabulary richness in spoken language depends on the brain status characterized by the semantic knowledge-related brain structure and its activation dissimilarity with the precuneus, a core region of the default mode network.

Association between social comparison orientation and hippocampal properties in older adults: A multimodal MRI study

Social comparison orientation (SCO) refers to the tendency to compare oneself with others and has two distinct dimensions: one about opinions and the other about abilities. Although dissociable neural mechanisms underlying the two dimensions of social comparison can be assumed, little is known about how each dimension of SCO is associated with cognitive and brain health among older adults. To investigate this, we analyzed the SCO scale questionnaire data, neuropsychological assessment data, and multimodal MRI data collected from 90 community-dwelling older adults. We found that global cognitive performance was positively correlated with the score of the opinion subscale but not with the score of the ability subscale and the total score. Similarly, hippocampal volume was positively correlated with opinion score alone. Additionally, the resting-state functional connectivity between the hippocampal seed and the default mode network showed a positive correlation only with the opinion score. Moreover, fractional anisotropy in the hippocampal cingulum was positively correlated with opinion score only. These findings suggest that global cognition and hippocampal properties in older age are associated with the SCO of opinion, which could reflect a regular habit of performing the types of cognitively demanding activities involved in evaluation of self and other opinions.

Autobiographical event memory and aging: older adults get the gist

We propose that older adults' ability to retrieve episodic autobiographical events, although often viewed through a lens of decline, reveals much about what is preserved and prioritized in cognitive aging. Central to our proposal is the idea that the so-called gist of an autobiographical event is not only spared with normal aging but also well adapted to serve memory-guided behavior in older age. To support our proposal, we review cognitive and brain evidence indicating an age-related shift toward gist memory. We then discuss why this shift likely arises from more than age-related decline and instead partly reflects a natural, arguably adaptive, outcome of experience, motivation, and mode-of-thinking factors. Our proposal reveals an upside of age-related memory changes and identifies important research questions.

The atypical functional connectivity of Broca's area at multiple frequency bands in autism spectrum disorder

As a developmental disorder, autism spectrum disorder (ASD) has drawn much attention due to its severe impacts on one's language capacity. Broca's area, an important brain region of the language network, is largely involved in language-related functions. Using the Autism Brain Image Data Exchange (ABIDE) dataset, a mega-analysis was performed involving a total of 1454 participants (including 618 individuals with ASD and 836 healthy controls (HCs). To detect the neural pathophysiological mechanism of ASD from the perspective of language, we conducted a functional connectivity (FC) analysis with Broca's area as the seed in multiple frequency bands (conventional: 0.01-0.08 Hz; slow-4: 0.027-0.073 Hz; slow-5: 0.01-0.027 Hz). We found that compared with HC, ASD patients demonstrated increased FC in the left thalamus, left precuneus, left anterior cingulate and paracingulate gyri, and left medial orbital of the superior frontal gyrus in the conventional frequency band (0.01-0.08 Hz). The results of the slow-5 frequency band (0.01-0.027 Hz) presented increased FC values of the left precuneus, left medial orbital of the superior frontal gyrus, right medial orbital of the superior frontal gyrus and right thalamus. No significant cluster was detected in the slow-4 frequency band (0.027-0.073 Hz). In conclusion, the abnormal functional connectivity in patients with ASD has frequency-specific properties. Furthermore, the slow-5 frequency band (0.01-0.027 Hz) mainly contributed to the findings of the conventional frequency band (0.01-0.08 Hz). The current study might shed new light on the neural pathophysiological mechanism of language impairments in people with ASD.

Patterns of brain activity associated with nostalgia: a social-cognitive neuroscience perspective

Nostalgia arises from tender and yearnful reflection on meaningful life events or important persons from one's past. In the last two decades, the literature has documented a variety of ways in which nostalgia benefits psychological well-being. Only a handful of studies, however, have addressed the neural basis of the emotion. In this prospective review, we postulate a neural model of nostalgia. Self-reflection, autobiographical memory, regulatory capacity and reward are core components of the emotion. Thus, nostalgia involves brain activities implicated in self-reflection processing (medial prefrontal cortex, posterior cingulate cortex and precuneus), autobiographical memory processing (hippocampus, medial prefrontal cortex, posterior cingulate cortex and precuneus), emotion regulation processing (anterior cingulate cortex and medial prefrontal cortex) and reward processing (striatum, substantia nigra, ventral tegmental area and ventromedial prefrontal cortex). Nostalgia's potential to modulate activity in these core neural substrates has both theoretical and applied implications.

Medial Prefrontal Activity During Self-Other Judgments is Modulated by Relationship Need Fulfillment

The medial prefrontal cortex (MPFC) plays an important role in representing semantic self-knowledge. Studies comparing semantic self-judgments with judgments of close others suggest that interpersonal closeness may influence the degree to which the MPFC differentiates self and other. We used optical neuroimaging to examine if support for competence, relatedness, and autonomy from relationship partners moderates MPFC activity during a personality judgement task. Participants (N = 109) were asked to judge the descriptive accuracy of trait adjectives for both themselves and a friend. Participants who reported lower need fulfillment with their friend showed elevated activity only in the self-judgment condition; in contrast, participants who reported higher need fulfillment with their friend showed similarly high levels of MPFC activity across the conditions. These results are consistent with the idea that the MPFC differentially represents others on the basis of the need fulfillment experienced within the relationship.

Differences in working memory coding of biological motion attributed to oneself and others

The question how the brain distinguishes between information about self and others is of fundamental interest to both philosophy and neuroscience. In this functional magnetic resonance imaging (fMRI) study, we sought to distinguish the neural substrates of representing a full‐body movement as one's movement and as someone else's movement. Participants performed a delayed match‐to‐sample working memory task where a retained full‐body movement (displayed using point‐light walkers) was arbitrarily labeled as one's own movement or as performed by someone else. By using arbitrary associations we aimed to address a limitation of previous studies, namely that our own movements are more familiar to us than movements of other people. A searchlight multivariate decoding analysis was used to test where information about types of movement and about self‐association was coded. Movement specific activation patterns were found in a network of regions also involved in perceptual processing of movement stimuli, however not in early sensory regions. Information about whether a memorized movement was associated with the self or with another person was found to be coded by activity in the left middle frontal gyrus (MFG), left inferior frontal gyrus (IFG), bilateral supplementary motor area, and (at reduced threshold) in the left temporoparietal junction (TPJ). These areas are frequently reported as involved in action understanding (IFG, MFG) and domain‐general self/other distinction (TPJ). Finally, in univariate analysis we found that selecting a self‐associated movement for retention was related to increased activity in the ventral medial prefrontal cortex.

Individual differences in the relationship between episodic detail generation and resting state functional connectivity vary with age

The ability to generate episodic details while recollecting autobiographical events is believed to depend on a collection of brain regions that form a posterior medial network (PMN). How age-related differences in episodic detail generation relate to the PMN, however, remains unclear. The present study sought to examine individual differences, and the role of age, in PMN resting state functional connectivity (rsFC) associations with episodic detail generation. Late middle-aged and older adults (N = 41, ages 52-81), and young adults (N = 21, ages 19-35) were asked to describe recent personal events, and these memory narratives were coded for episodic, semantic and 'miscellaneous' details. Independent components analysis and regions-of-interest analyses were used to assess rsFC within the PMN separately for anterior connections (hippocampal and medial prefrontal) and posterior connections (hippocampal, parahippocampal and parieto-occipital), as these connections purportedly serve different functional roles in episodic detail generation. Compared to younger adults, older adults produced memory narratives with lower episodic specificity (ratio of episodic:total details) and a greater amount of semantic detail. Among the older adults, episodic detail amounts and episodic specificity were reduced with increasing age. There were no significant age differences in PMN rsFC. Stronger anterior PMN rsFC was related to lower episodic detail in the older adult group, but not in the young. Among the older adults, increasing age brought on an association between increased anterior PMN rsFC and reduced episodic specificity. In contrast, increasing age brought on an association between increased posterior PMN rsFC and increased semantic detail. The present study provides evidence that functional connectivity within the PMN, particularly anterior PMN, tracks individual differences in the amount of episodic details retrieved by older adults. Furthermore, these brain-behavior relationships appear to be age-specific, indicating that some process within aging alters the nature of how anterior PMN rsFC and episodic detail relate to each other. Whether this process entails an age-related loss of integrity to the PMN, or an age-related shift toward semantic retrieval, remains to be determined.

In search of a naturalistic neuroimaging approach: Exploration of general feasibility through the case of VR-fMRI and application in the domain of episodic memory

Virtual Reality (VR) is an increasingly widespread tool for research as it allows the creation of experiments taking place in multimodal and daily-life-like environments, while keeping a strong experimental control. Adding neuroimaging to VR leads to a better understanding of the underlying brain networks activated during a naturalistic task, whether for research purposes or rehabilitation. The present paper focuses on the specific use of concurrent VR and fMRI and its technical challenges and feasibility, with a brief examination of the general existing solutions. Following the PRISMA guidelines, the review investigates the particular case of how VR-fMRI has explored episodic memory so far, with a comparison of object- and place-based episodic memory. This review confirms the involvement of cerebral regions well-known to be implicated in episodic memory and unravels other regions devoted to bodily and narrative aspects of the self, promoting new avenues of research in the domain of naturalistic episodic memory. Future studies should develop more immersive and interactive virtual neuroimaging features to increase ecological and embodied neurocognition aspects.

Autobiographical memory unknown: Pervasive autobiographical memory loss encompassing personality trait knowledge in an individual with medial temporal lobe amnesia

Autobiographical memory consists of distinct memory types varying from highly abstract to episodic. Self trait knowledge, which is considered one of the more abstract types of autobiographical memory, is thought to rely on regions of the autobiographical memory neural network implicated in schema representation, including the ventromedial prefrontal cortex, and critically, not the medial temporal lobes. The current case study introduces an individual who experienced bilateral posterior cerebral artery strokes resulting in extensive medial temporal lobe damage with sparing of the ventromedial prefrontal cortex. Interestingly, in addition to severe retrograde and anterograde episodic and autobiographical fact amnesia, this individual's self trait knowledge was impaired for his current and pre-morbid personality traits. Yet, further assessment revealed that this individual had preserved conceptual knowledge for personality traits, could reliably and accurately rate another person's traits, and could access his own self-concept in a variety of ways. In addition to autobiographical memory loss, he demonstrated impairment on non-personal semantic memory tests, most notably on tests requiring retrieval of unique knowledge. This rare case of amnesia suggests a previously unreported role for the medial temporal lobes in self trait knowledge, which we propose reflects the critical role of this neural region in the storage and retrieval of personal semantics that are experience-near, meaning autobiographical facts grounded in spatiotemporal contexts.

The nature of the self: Neural analyses and heritability estimates of self-evaluations in middle childhood

How neural correlates of self-concept are influenced by environmental versus genetic factors is currently not fully understood. We investigated heritability estimates of behavioral and neural correlates of self-concept in middle childhood since this phase is an important time window for taking on new social roles in academic and social contexts. To do so, a validated self-concept fMRI task was applied in a twin sample of 345 participants aged between 7 and 9 years. In the self-concept condition, participants were asked to indicate whether academic and social traits applied to them whereas the control condition required trait categorization. The self-processing activation analyses (n = 234) revealed stronger medial prefrontal cortex (mPFC) activation for self than for control conditions. This effect was more pronounced for social-self than academic self-traits, whereas stronger dorsolateral prefrontal cortex (DLPFC) activation was observed for academic versus social self-evaluations. Behavioral genetic modeling (166 complete twin pairs) revealed that 25-52% of the variation in academic self-evaluations was explained by genetic factors, whereas 16-49% of the variation in social self-evaluations was explained by shared environmental factors. Neural genetic modeling (91 complete twin pairs) for variation in mPFC and anterior prefrontal cortex (PFC) activation for academic self-evaluations confirmed genetic and unique environmental influences, whereas anterior PFC activation for social self-evaluations was additionally influenced by shared environmental influences. This indicates that environmental context possibly has a larger impact on the behavioral and neural correlates of social self-concept at a young age. This is the first study demonstrating in a young twin sample that self-concept depends on both genetic and environmental factors, depending on the specific domain.

Episodic Autobiographical Memory Impairment and Differences in Pronoun Use: Study of Self-Awareness in Functional Amnesia and Transient Global Amnesia

The subjective experience associated to memory processing is the core of the definition of episodic autobiographical memory (EAM). However, while it is widely known that amnesia affects the content of memories, few studies focused on the consequences of an impairment of EAM on the subjective self, also called the I-self. In the present study, we explored the I-self in two puzzling disorders that affect EAM: functional amnesia, which has an impact on autobiographical memory, and transient global amnesia (TGA), which only affects episodic memory. I-self was assessed through an original measure of self-integration in autobiographical narratives, namely the use of general or personal pronouns. Results showed that patients with functional amnesia tended to use general pronouns, whereas patients with TGA preferentially used the first person. The link between I-self and depersonalization-derealisation tendencies was also explored, showing dissociative tendencies in patients with functional amnesia but not in patients with TGA. We discuss these results from a combined neuropsychological and psychopathological perspective, with a view to proposing an explanatory model of the links between self-awareness and the episodic component of autobiographical memory.

Memory, Future Thinking, and the Self. In Honour of Martial Van Der Linden

Over the past 20 years, much progress has been made in understanding the relations between memory and future thinking, and their role in shaping our sense of self and identity. My own interest in these research questions owes much to Martial Van der Linden, with whom I had the chance to interact closely for several years. The purpose of this article is to pay tribute to him by reviewing the work we initiated together on autobiographical memory and future-oriented thinking. I first review our early work on the relationship between memory and future thinking and discuss their role in self-representation. Then, I provide an overview of the underlying neural bases and describe the alterations of autobiographical thinking that characterize certain psychological disorders. Finally, I outline an integrative framework that I recently proposed to account for the cognitive structure of past and future autobiographical thinking.

Autobiographical Memory Fluency Reductions in Cognitively Unimpaired Middle-Aged and Older Adults at Increased Risk for Alzheimer's Disease Dementia

OBJECTIVE

Recent research has revealed that cognitively unimpaired older adults who are at higher risk for developing Alzheimer's disease (AD) dementia often exhibit subtle cognitive alterations in their neuropsychological profiles. Emerging evidence suggests that autobiographical memory, which is memory for personal events and knowledge, may be sensitive to early AD-related cognitive alterations. In the present study, we investigated whether the rapid generation of autobiographical memory category exemplars, a retrieval process that taxes the neural network that is vulnerable to early AD, is compromised in cognitively unimpaired middle-aged and older carriers of the e4 allele of the apolipoprotein E gene (APOE4), which increases risk for AD dementia.

METHODS

In addition to standard neuropsychological tests, we administered a fluency task that requires generating exemplars for two types of autobiographical memory, namely episodic memories and personal semantics, to a group of cognitively unimpaired middle-aged and older adults (n = 45) enriched with APOE4 carriers (n = 20).

RESULTS

While no APOE4 deficits were found on standard neuropsychological tests, episodic and personal semantic exemplar generation was reduced in the APOE4 group.

DISCUSSION

Autobiographical memory aberrations associated with a higher risk for AD are evident in fluency and affect both episodic memory and personal semantics.

Self-representation in Kleine-Levin syndrome: a single case fMRI study

Kleine-Levin syndrome (KLS) is characterized by recurrent episodes of hypersomnia, compulsive hyperphagia, disinhibition, hypersexuality and self modifications. To investigate the Self, we used afunctional magnetic resonance imaging paradigm evaluating Self-reference processing (SRP) and Self-reference effect (SRE) in a17-year-old male adolescent at the end of an episode. We observed enhanced activations in right hemisphere and posterior areas- associated with physical Self representations- during the SRP condition, while during the SRE condition, enhanced activations in bilateral but prevailing left frontal areas- associated with the conceptual Self. These results suggest amodified Self during aKLS episode being more physically grounded.

Episodic-like memory is preserved with age in cuttlefish

Episodic memory, remembering past experiences based on unique what–where–when components, declines during ageing in humans, as does episodic-like memory in non-human mammals. By contrast, semantic memory, remembering learnt knowledge without recalling unique what–where–when features, remains relatively intact with advancing age. The age-related decline in episodic memory likely stems from the deteriorating function of the hippocampus in the brain. Whether episodic memory can deteriorate with age in species that lack a hippocampus is unknown. Cuttlefish are molluscs that lack a hippocampus. We test both semantic-like and episodic-like memory in sub-adults and aged-adults nearing senescence (n = 6 per cohort). In the semantic-like memory task, cuttlefish had to learn that the location of a food resource was dependent on the time of day. Performance, measured as proportion of correct trials, was comparable across age groups. In the episodic-like memory task, cuttlefish had to solve a foraging task by retrieving what–where–when information about a past event with unique spatio-temporal features. In this task, performance was comparable across age groups; however, aged-adults reached the success criterion (8/10 correct choices in consecutive trials) significantly faster than sub-adults. Contrary to other animals, episodic-like memory is preserved in aged cuttlefish, suggesting that memory deterioration is delayed in this species.

The ERP correlates of self-knowledge in ageing

Self-knowledge is a type of personal semantic knowledge that concerns one's self-image and personal identity. It has most often been operationalized as the summary of one's personality traits ("I am a stubborn person"). Interestingly, recent studies have revealed that the neural correlates of self-knowledge can be dissociated from those of general semantic and episodic memory in young adults. However, studies of "dedifferentiation" or loss of distinctiveness of neural representations in ageing suggest that the neural correlates of self-knowledge might be less distinct from those of semantic and episodic memory in older adults. We investigated this question in an event-related potential (ERP) study with 28 young and 26 older adults while they categorised personality traits for their self-relevance (self-knowledge conditions), and their relevance to certain groups of people (general semantic condition). Participants then performed a recognition test for previously seen traits (episodic condition). The amplitude of the late positive component (LPC), associated with episodic recollection processes, differentiated the self-knowledge, general semantic, and episodic conditions in young adults, but not in older adults. However, in older adults, participants with higher composite episodic memory scores had more differentiated LPC amplitudes across experimental conditions. Moreover, consistent with the fact that age-related neural dedifferentiation may be material and region specific, in both age groups some differences between memory types were observed for the N400 component, associated with semantic processing. Taken together, these findings suggest that declarative memory subtypes are less distinct in ageing, but that the amount of differentiation varies with episodic memory function.

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.

Overlapping Functional Representations of Self- and Other-Related Thought are Separable Through Multivoxel Pattern Classification

Self-reflection and thinking about the thoughts and behaviors of others are important skills for humans to function in the social world. These two processes overlap in terms of the component processes involved, and share overlapping functional organizations within the human brain, in particular within the medial prefrontal cortex (MPFC). Several functional models have been proposed to explain these two processes, but none has directly explored the extent to which they are distinctly represented within different parts of the brain. This study used multivoxel pattern classification to quantify the separability of self- and other-related thought in the MPFC and expanded this question to the entire brain. Using a large-scale mega-analytic dataset, spanning three separate studies (n = 142), we find that self- and other-related thought can be reliably distinguished above chance within the MPFC, posterior cingulate cortex and temporal lobes. We highlight subcomponents of the ventral MPFC that are particularly important in representing self-related thought, and subcomponents of the orbitofrontal cortex robustly involved in representing other-related thought. Our findings indicate that representations of self- and other-related thought in the human brain are described best by a distributed pattern rather than stark localization or a purely ventral to dorsal linear gradient in the MPFC.

The posterior crus II cerebellum is specialized for social mentalizing and emotional self-experiences: a meta-analysis

This meta-analysis explores the role of the posterior cerebellum Crus I/II in social mentalizing. We identified over 200 functional magnetic resonance imaging (fMRI) studies via NeuroSynth that met our inclusion criteria and fell within bilateral Crus II areas related to ‘sequencing’ during mentalizing (coordinates ±24 −76 −40; from earlier studies) and mere social ‘mentalizing’ or self-related emotional cognition (coordinates ±26 −84 −34; from NeuroSynth), located in the cerebellar mentalizing network. A large majority of these studies (74%) involved mentalizing or self-related emotional cognition. Other functions formed small minorities. This high incidence in Crus II compares very favorably against the lower base rate for mentalizing and self-related emotions (around 35%) across the whole brain as revealed in NeuroSynth. In contrast, there was much less support for a similar role of Crus I (coordinates −40 −70 −40 from earlier ‘sequencing’ studies) as only 35% of the studies were related to mentalizing or self-related emotions. The present findings show that a domain-specific social mentalizing functionality is supported in the cerebellar Crus II. This has important implications for theories of the social cerebellum focusing on sequencing of social actions, and for cerebellar neurostimulation treatments.

The Development of Identity Fusion

The fusion of personal and group identities can lead to self-sacrificial progroup behavior, from acts of charity to violent extremism. Two pathways to identity fusion-via shared biology and shared experiences-have been proposed. In this article, we elucidate a new developmental account of the origins and mechanisms of these two pathways to identity fusion from childhood to adulthood. Whereas fusion based on shared biology occurs from early childhood cued by phenotypic similarity, fusion based on episodic memories of shared experiences is not possible until midadolescence and relies on suitable bonding experiences (e.g., painful initiation rituals, emotionally intense team sports). The critical development that enables fusion based on shared experiences is autobiographical reasoning, which entails connecting one's past experiences to the present self. Autobiographical reasoning begins in adolescence, which may explain the flourishing of fusion in late adolescence and young adulthood relative to other life periods. Fusion via either pathway is linked to strong progroup behavior. We outline a program of empirical research on the development of identity fusion while addressing relevant methodological challenges. A developmental framework may help foster efforts to harness identity fusion for peaceful rather than violent forms of self-sacrifice for the group.

Mind-Wandering in Adolescents Predicts Worse Affect and Is Linked to Aberrant Default Mode Network-Salience Network Connectivity

OBJECTIVE

Understanding the fluctuating emotional and cognitive states of adolescents with depressive symptoms requires fine-grained and naturalistic measurements. This study used ecological momentary assessment (EMA) to investigate the affective correlates and consequences of mind-wandering in adolescents with anhedonia (AH) and typically developing (TD) controls. In addition, we examined the association between mind-wandering and resting state functional connectivity between the medial prefrontal cortex (mPFC), a core hub of the default mode network (DMN) linked to internally oriented mentation, and networks linked to attentional control (dorsal attention network [DAN]) and affect/salience detection (salience network [SN]).

METHOD

A total of 65 adolescents, aged 12 to 18 years (TD = 36; AH = 29), completed a resting state functional magnetic resonance imaging scan and subsequently used a smartphone application for ecological momentary assessment (EMA) data collection (2-3 times/d for 5 days). Each survey (N = 678) prompted adolescents to report on their current positive and negative affect (PA and NA), cognition, and activity.

RESULTS

The frequency of mind-wandering was higher for AH (70.0% of EMA samples) relative to TD (59.2%) participants, and the participants with AH were more likely to mind-wander to unpleasant content. Mind-wandering was associated with higher concurrent NA, even when controlling for plausible confounds (eg, current activity, social companion, rumination). Time-lagged analyses revealed a bidirectional association between mind-wandering and PA. Greater levels of mind-wandering within the AH group were associated with stronger mPFC-SN/DAN connectivity.

CONCLUSION

Rates of mind-wandering were high, especially among adolescents with anhedonia, and predicted worse affect. The relation between mind-wandering and enhanced mPFC-SN coupling may reflect heightened bottom-up influence of affective and sensory salience on DMN-mediated internally oriented thought.

Neural Safeguards against Global Impacts of Memory Modification on Identity: Ethical and Practical Considerations

Zawadzki and Adamczyk question whether removal of painful memories that anchor one’s narrative identity might leave behind a “free-floating” self plagued by feelings of inauthenticity. We argue that this scenario is unlikely, based on evidence that suggests our neural systems – especially those critical to human functioning1 – are naturally protected against minor, localized disruptions due to their synergistic distribution and redundancy2. For the same reason that artificial deep neural networks are increasingly designed to incorporate computational redundancy (especially those with safety-critical applications, such as self-driving cars), our own neural networks contain a degree of “cognitive reserve”3 to help mitigate against total system failure4,5 by drawing upon supplementary neural networks and forming new and more efficient connections (neuroplasticity) to compensate for disruptions.6 Neural representations of identity, a construct which evolutionary psychologists and behavioral ecologists argue is critical for survival at the individual, group and species levels7, are likely to incorporate such redundancy as a safeguard. The distribution of memory components across different brain regions supports the notion of cognitive reserve in the case of narrative identity. This arrangement complicates the capacity of optogenetic interventions to effectively erase complex autobiographical memories. Even if it were possible, we argue that disruptions to one’s identity and values are not necessarily ethically problematic, and must be viewed within the context of a risk-benefit ratio in which autonomously choosing to modify one’s debilitating or pathology-causing memories may confer benefits that outweigh potential challenges of identity reconstruction and (temporary) feelings of inauthenticity.

Learning in Infancy Is Active, Endogenously Motivated, and Depends on the Prefrontal Cortices

A common view of learning in infancy emphasizes the role of incidental sensory experiences from which increasingly abstract statistical regularities are extracted. In this view, infant brains initially support basic sensory and motor functions, followed by maturation of higher-level association cortex. Here, we critique this view and posit that, by contrast and more like adults, infants are active, endogenously motivated learners who structure their own learning through flexible selection of attentional targets and active interventions on their environment. We further argue that the infant brain, and particularly the prefrontal cortex (PFC), is well equipped to support these learning behaviors. We review recent progress in characterizing the function of the infant PFC, which suggests that, as in adults, the PFC is functionally specialized and highly connected. Together, we present an integrative account of infant minds and brains, in which the infant PFC represents multiple intrinsic motivations, which are leveraged for active learning.

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.

Memory dysfunctions

Since the seminal work on the patient HM, who in his adulthood presented an acquired amnesic syndrome following the resection of the bilateral temporal lobe, other research has described several cases of isolated memory dysfunction in children. This chapter presents developmental and long-lasting memory disorders emerging from an organic or neurologic cause at birth or in infancy. More notably, we focus on developmental amnesic syndrome caused by neonatal bihippocampal damage and memory dysfunction caused by medial temporal developmental epilepsy. We describe these two pediatric populations and present the consequences of hippocampal/medial temporal lobe damage in the development of memory systems. We review episodic memory deficits in children with developmental amnesia and temporal lobe epilepsy and highlight their impact on new learning, personal memories, and independent life. Finally, we provide a brief overview of some of the insights and debates emerging from classic work and recent advances in the context of episodic memory dysfunction displayed by children with hippocampal/medial temporal lobe amnesia and propose new perspectives in child neuropsychology of memory, suggesting new avenues for more ecologic memory assessment and rehabilitation.

Personal familiarity of music and its cerebral effect on subsequent speech processing

Despite the obvious personal relevance of some musical pieces, the cerebral mechanisms associated with listening to personally familiar music and its effects on subsequent brain functioning have not been specifically evaluated yet. We measured cerebral correlates with functional magnetic resonance imaging (fMRI) while composers listened to three types of musical excerpts varying in personal familiarity and self (familiar own/composition, familiar other/favorite or unfamiliar other/unknown music) followed by sequences of names of individuals also varying in personal familiarity and self (familiar own/own name, familiar other/close friend and unfamiliar other/unknown name). Listening to music with autobiographical contents (familiar own and/or other) recruited a fronto-parietal network including mainly the dorsolateral prefrontal cortex, the supramarginal/angular gyri and the precuneus. Additionally, while listening to familiar other music (favorite) was associated with the activation of reward and emotion networks (e.g. the striatum), familiar own music (compositions) engaged brain regions underpinning self-reference (e.g. the medial prefrontal cortex) and visuo-motor imagery. The present findings further suggested that familiar music with self-related reference (compositions) leads to an enhanced activation of the autobiographical network during subsequent familiar name processing (as compared to music without self-related reference); among these structures, the precuneus seems to play a central role in personally familiar processing.

Depression is associated with hyperconnectivity of an introspective socio-affective network during the recall of formative relationship episodes

BACKGROUND

Depression and the experience of early adversity are associated with impairments in interpersonal and social cognitive functioning. The neural mechanisms involved in these impairments remain insufficiently understood.

METHODS

In a sample of 48 depressed and 50 healthy participants, we explored seed-to-voxel functional connectivity (FC) during the recall of formative relationship episodes using functional magnetic resonance imaging.

RESULTS

While depressive symptoms were associated with increased FC of brain regions that form an introspective socio-affective network, such as the precuneus, bilateral anterior insula, dorsal anterior cingulate cortex, left amygdala, and medial prefrontal cortex, early adversity linked to decreased FC of brain regions mediating emotion processing such as the bilateral anterior insula and increased FC of the bilateral parahippocampal gyrus.

LIMITATIONS

We report both results that are corrected for the number of seeds tested in FC analyses using strict Bonferroni adjustments and unadjusted results as part of an exploratory analysis.

DISCUSSION

Our findings suggest that depression and early adversity are associated with differential FC patterns in the brain during the recall of formative relationship episodes. Hyperconnectivity of an introspective socio-affective network associated with depressive symptoms may link to enhanced self-focus and emotional reactivity. Patterns of neural activation associated with early adversity may underpin numbed affective states or enhanced affective memory regulation. Overall, these findings inform about the neural underpinnings of a reflective ability that is predictive of the adaptation to depression and to early adversity and relevant for psychotherapy outcomes.

Self-esteem and cultural worldview buffer mortality salience effects on responses to self-face: Distinct neural mediators

Terror management theory proposes cultural worldview and self-esteem as two buffers against death anxiety. The neural mediators of these buffering effects, however, have not been fully understood. The present work investigated neural mediation mechanisms between self-esteem/cultural trait (self-construal) and mortality salience (MS) effects on self-face processing. We found that MS (vs. NA) priming eliminated self-face advantage in behavioral judgments of face-orientation in low self-esteem individuals and reduced self-face advantage in behavioral judgments of facial-familiarity in individuals with high interdependent self-construals. Our functional magnetic resonance imaging (fMRI) results showed that, following MS priming, insular activities mediated the relationship between self-esteem and self-face advantage in face-orientation judgments, whereas dorsal medial prefrontal activity mediated the relationship between interdependent self-construal and self-face advantage in face-familiarity judgments. Our findings suggest that distinct neural mechanisms are engaged in mediating the relationships between self-esteem/cultural trait and MS effects on the emotional and cognitive processes of self-relevant information.

Brain mechanisms of insomnia: new perspectives on causes and consequences

While insomnia is the second most common mental disorder, progress in our understanding of underlying neurobiological mechanisms has been limited. The present review addresses the definition and prevalence of insomnia and explores its subjective and objective characteristics across the 24-hour day. Subsequently, the review extensively addresses how the vulnerability to develop insomnia is affected by genetic variants, early life stress, major life events, and brain structure and function. Further supported by the clear mental health risks conveyed by insomnia, the integrated findings suggest that the vulnerability to develop insomnia could rather be found in brain circuits regulating emotion and arousal than in circuits involved in circadian and homeostatic sleep regulation. Finally, a testable model is presented. The model proposes that in people with a vulnerability to develop insomnia, the locus coeruleus is more sensitive to-or receives more input from-the salience network and related circuits, even during rapid eye movement sleep, when it should normally be sound asleep. This vulnerability may ignite a downward spiral of insufficient overnight adaptation to distress, resulting in accumulating hyperarousal, which, in turn, impedes restful sleep and moreover increases the risk of other mental health adversity. Sensitized brain circuits are likely to be subjectively experienced as "sleeping with one eye open". The proposed model opens up the possibility for novel intervention studies and animal studies, thus accelerating the ignition of a neuroscience of insomnia, which is direly needed for better treatment.