Brain activity and functional coupling changes associated with self-reference effect during both encoding and retrieval

The oscillatory fingerprints of self-prioritization: Novel markers in spectral EEG for self-relevant processing

Self-prioritization is a very influential modulator of human information processing. Still, little is known about the time-frequency dynamics of the self-prioritization network. In this EEG study, we used the familiarity-confound free matching task to investigate the spectral dynamics of self-prioritization and their underlying cognitive functions in a drift-diffusion model. Participants (N = 40) repeatedly associated arbitrary geometric shapes with either "the self" or "a stranger." Behavioral results demonstrated prominent self-prioritization effects (SPEs) in reaction time and accuracy. Remarkably, EEG cluster analysis also revealed two significant SPEs, one in delta/theta power (2-7 Hz) and one in beta power (19-29 Hz). Drift-diffusion modeling indicated that beta activity was associated with evidence accumulation, whereas delta/theta activity was associated with response selection. The decreased beta suppression of the SPE might indicate more efficient sensorimotor processing of self-associated stimulus-response features, whereas the increased delta/theta SPE might refer to the facilitated retrieval of self-relevant features across a widely distributed associative self-network. These novel oscillatory biomarkers of self-prioritization indicate their function as an associative glue for the self-concept.

Aberrant connectivity in the right amygdala and right middle temporal gyrus before and after a suicide attempt: Examining markers of suicide risk

Functional neuroimaging has the potential to help identify those at risk for self-injurious thoughts and behaviors, as well as inform neurobiological mechanisms that contribute to suicide. Based on whole-brain patterns of functional connectivity, our previous work identified right amygdala and right middle temporal gyrus (MTG) connectivity patterns that differentiated Veterans with a history of a suicide attempt (SA) from a Veteran control group. In this study, we aimed to replicate and extend our previous findings by examining whether this aberrant connectivity was present prior to and after a SA. In a trauma-exposed Veteran sample (92 % male, mean age = 34), we characterized if the right amygdala and right MTG connectivity differed between a psychiatric control sample (n = 56) and an independent sample of Veterans with a history of SA (n = 17), using fMRI data before and after the SA. Right MTG and amygdala connectivity differed between Veterans with and without a history of SA (replication), while MTG connectivity also distinguished Veterans prior to engaging in a SA (extension). In a second study, neither MTG or amygdala connectivity differed between those with current suicidal ideation (n = 27) relative to matched psychiatric controls (n = 27). These results indicate a potential stable marker of suicide risk (right MTG connectivity) as well as a potential marker of acute risk of or recent SA (right amygdala connectivity) that are independent of current ideation.

Camera-based visual feedback learning aid for recovering sense of smell and taste in COVID-19 survivors: a proof-of-concept study

Introduction

A significant proportion of people report persistent COVID-19-related anosmia, hyposmia or parosmia, often accompanied with ageusia, hypogeusia or dysgeusia. Here, we present a proof-of-concept study that assessed the feasibility and acceptability of a new Camera-Based Visual Feedback Learning Aid (CVFLA) and explored its potential to restore or improve persistent COVID-19-related smell and/or taste impairment.

Methods

Fifteen adult participants with persistent smell and/or taste impairment were randomly allocated to 7-, 14-, or 21-days baseline of symptom monitoring before receiving the intervention in up to 10 sessions (length and frequency determined by participant's preference and progress) using a specialised CVFLA apparatus (patent no. 10186160). Smell and taste were assessed pre- and post-intervention subjectively, and also objectively using the ODOFIN Taste Strips and Sniffin Sticks. Participant feedback about their experience of receiving CVFLA was obtained via a semi-structured interview conducted by someone not involved in delivering the intervention.

Results

The intervention was extremely well received, with no dropouts related to the intervention. There was also a significant improvement in smell and taste from pre- to post-CVFLA intervention (mean number of sessions = 7.46, SD = 2.55; total duration = 389.96 min, SD = 150.93) both in subjective and objective measures. All participants, except one, reported experiencing some improvement from the 2nd or 3rd session.

Discussion

This new CVFLA intervention shows promise in improving COVID-19 related impairment in smell and taste with a very high level of acceptability. Further studies with larger samples are required to confirm its potential in restoring, improving or correcting smell and/or taste impairment in relevant clinical and non-clinical groups.

Sensitivity of late ERP old/new effects in source memory to self-referential encoding focus and stimulus emotionality

In episodic memory, the old/new effect, the contrast of the waveforms elicited by the correctly recognized studied items and the correctly rejected novel items, has been broadly concerned. However, the contribution of self-referential encoding to the old/new effect in source memory (i.e., source-SRE), is far from clarification; further, it remains unclear whether the contribution is susceptible to the factor of stimulus emotionality. To address these issues, adopting the event-related potential (ERP) technique, this study applied words of three types of emotional valences (positive, neutral, vs. negative) in the self-focus vs. external-focus encoding tasks. In the course of the test, four ERP old/new effects were identified: (a) the familiarity- and recollection-reflected mid-frontal effect (FN400) and late positive component (LPC) were both independent of source-SRE and stimulus emotionality; (b) the reconstruction-driven late posterior negativity (LPN) exhibited an adverse pattern of source-SRE and was susceptible to the emotional valence by encoding focus; and (c) the right frontal old/new effect (RFE), reflecting post-retrieval process, exhibited a source-SRE in emotional words. These effects provide compelling evidence for the influences of both stimulus valence and encoding focus on SRE in source memory, especially during the late processes. Further directions considering more perspectives are put forward.

Neurophysiological correlates of disorder-related autobiographical memory in anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) is characterized by an overgeneralization of food/body-related autobiographical memories (AM). This is regarded as an emotion regulation strategy with adverse long-term effects implicated in disorder maintenance and treatment resistance. Therefore, we aimed to examine neural correlates of food/body-related AM-recall in AN.

METHODS

Twenty-nine female patients with AN and 30 medication-free age-sex-matched normal-weight healthy controls (HC) underwent functional magnetic resonance imaging while recalling AMs in response to food/body-related and neutral cue words. To control for general knowledge retrieval, participants engaged in a semantic generation and riser detection task.

RESULTS

In comparison to HC, patients with AN generated fewer and less specific AMs in response to food/body-related words, but not for neutral cue words. Group comparisons revealed reduced activation in regions associated with self-referential processing and memory retrieval (precuneus and angular gyrus) during the retrieval of specific food/body-related AM in patients with AN. Brain connectivity in regions associated with memory functioning and executive control was reduced in patients with AN during the retrieval of specific food/body-related AM. Finally, resting-state functional connectivity analysis revealed no differences between groups, arguing against a general underlying disconnection of brain networks implicated in memory and emotional processing in AN.

CONCLUSIONS

These results indicate impaired neural processing of food/body-related AM in AN, with a reduced involvement of regions involved in self-referential processing. Our findings are discussed as possible neuronal correlates of emotional avoidance in AN and provide new insights of AN-pathophysiology underscoring the importance of targeting dysfunctional emotion regulation strategies during treatment.

Respiratory sinus arrhythmia during biofeedback is linked to persistent improvements in attention, short-term memory, and positive self-referential episodic memory

Background

Heart rate variability (HRV) biofeedback, an intervention based on the voluntary self-regulation of autonomic parameters, has been shown to affect prefrontal brain functioning and improve executive functions. The interest in using HRV biofeedback as cognitive training is typically ascribed to parasympathetic activation and optimized physiological functioning deriving from increased cardiac vagal control. However, the persistence of cognitive effects is poorly studied and their association with biofeedback-evoked autonomic changes has not yet been explored. In addition, no study has so far investigated the influence of HRV biofeedback in adults on long-term episodic memory, which is particularly concerned with self-referential encoding processing.

Methods

In the present study, a novel training system was developed integrating HRV and respiratory biofeedback into an immersive virtual reality environment to enhance training efficacy. Twenty-two young healthy adults were subjected to a blinded randomized placebo-controlled experiment, including six self-regulation training sessions, to evaluate the effect of biofeedback on autonomic and cognitive changes. Cardiac vagal control was assessed before, during, and 5 min after each training session. Executive functions, episodic memory, and the self-referential encoding effect were evaluated 1 week before and after the training program using a set of validated tasks.

Results

Linear mixed-effects models showed that HRV biofeedback greatly stimulated respiratory sinus arrhythmia during and after training. Moreover, it improved the attentional capabilities required for the identification and discrimination of stimuli ( η p 2 = 0.17), auditory short-term memory ( η p 2 = 0.23), and self-referential episodic memory recollection of positive stimuli ( η p 2 = 0.23). Episodic memory outcomes indicated that HRV biofeedback reinforced positive self-reference encoding processing. Cognitive changes were strongly dependent on the level of respiratory sinus arrhythmia evoked during self-regulation training.

Conclusion

The present study provides evidence that biofeedback moderates respiration-related cardiac vagal control, which in turn mediates improvements in several cognitive processes crucial for everyday functioning including episodic memory, that are maintained beyond the training period. The results highlight the interest in HRV biofeedback as an innovative research tool and medication-free therapeutic approach to affect autonomic and neurocognitive functioning. Finally, a neurocognitive model of biofeedback-supported autonomic self-regulation as a scaffolding for episodic memory is proposed.

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.

Late frontal positivity effects in Self-referential Memory: Unique to the Self?

The self-reference effect in memory (SRE), in which stimuli related to self are better remembered than other stimuli, has been studied often in the fMRI literature, but much less with EEG. In two experiments, we investigated how self-referencing modulated event-related potential (ERP) markers of the subsequent memory effect, testing whether the same components that reflect memory success are impacted or whether unique components are modulated by self-referencing. Participants were asked to evaluate whether an adjective accurately described either the self or a given other by making a yes/no key press during EEG recording. Then participants were given a surprise recognition memory test where they judged each adjective as old or new. We observed a main effect of self-relevance on a late positivity at right frontal electrodes. A very similar effect was observed when comparing words subsequently remembered to those that were forgotten. However, no interaction was found between self-relevance and subsequent memory, suggesting the frontal positivity is not exclusive to the SRE, but instead a reflection of deeper encoding that leads to better memory. Thus, this frontal positivity may be a marker of a deeper encoding process that is elicited by self-referencing but not exclusive to the SRE.

A conceptual space for episodic and semantic memory

I propose a model that places episodic, semantic, and other commonly studied forms of memory into the same conceptual space. The space is defined by three dimensions required for Tulving's episodic and semantic memory. An implicit-explicit dimension contrasts both episodic and semantic memory with common forms of implicit memory. A self-reference dimension contrasts episodes that occurred to one person with semantic knowledge. A scene dimension contrasts episodes that occurred in specific contexts with context-free semantic information. The three dimensions are evaluated against existing behavioral and neural evidence to evaluate both the model and the concepts underlying the study of human memory. Unlike a hierarchy, which has properties specific to each category, the dimensions have properties that extend throughout the conceptual space. Thus, the properties apply to all forms of existing and yet-to-be-discovered memory within the space. Empty locations in the proposed space are filled with existing phenomena that lack a clear place in current theories of memory, including reports of episodic-like memories for events reported to but not witnessed by a person, fictional narrative accounts, déjà vu, and implicit components contributing to personality, the self, and autobiographical memory.

Neural mechanisms supporting emotional and self-referential information processing and encoding in older and younger adults

Emotion and self-referential information can both enhance memory, but whether they do so via common mechanisms across the adult lifespan remains underexplored. To address this gap, the current study directly compared, within the same fMRI paradigm, the encoding of emotionally salient and self-referential information in older adults and younger adults. Behavioral results replicated the typical patterns of better memory for emotional than neutral information and for self-referential than non-self-referential materials; these memory enhancements were present for younger and older adults. In neural activity, young and older adults showed similar modulation by emotion, but there were substantial age differences in the way self-referential processing affected neural recruitment. Contrary to our hypothesis, we found little evidence for overlap in the neural mechanisms engaged for emotional and self-referential processing. These results reveal that-just as in cognitive domains-older adults can show similar performance to younger adults in socioemotional domains even though the two age groups engage distinct neural mechanisms. These findings demonstrate the need for future research delving into the neural mechanisms supporting older adults' memory benefits for socioemotional material.

Neural Activity During Self-referential Processing in Children at Risk for Depression

BACKGROUND

According to cognitive theories of depression, more negative and less positive self-schemas are thought to play a causal role in the disorder. Existing evidence speaks to the neural substrates of self-referential processes in both healthy and depressed individuals, but little is known about how the brain relates to self-referential processing in the context of depression risk in children. We therefore studied the neural substrates of self-referential processing in never-depressed preadolescent children at high and low risk for depression based on maternal depression history.

METHODS

A total of 87 never-depressed 10-12-year-old children (29 with maternal depression) completed a self-referential encoding task during a functional magnetic resonance imaging session, in which they were presented a series of positive and negative trait adjectives and endorsed whether each word was self-descriptive. Small volume correction analyses were conducted within 7 regions of interest that are important for self-referential and emotion-related processes.

RESULTS

Analyses of small volume correction indicated that high-risk children showed greater activation in the ventrolateral prefrontal cortex and ventromedial prefrontal cortex during the positive-word self-referential encoding task condition than low-risk children. Ventrolateral prefrontal cortex activation mediated the association between maternal depression and child depressive symptoms only when children had lower positive self-schemas, indicating that more positive self-schemas may protect at-risk children from developing depressive symptoms.

CONCLUSIONS

Cortical midline and prefrontal regions are important to self-, emotion-, and regulation-related processes. Heightened activation within these regions in never-depressed high-risk children indicates that these neurobiological substrates may mediate early vulnerability to depression in the context of cognitive processes relevant to self-concepts.

Electrophysiological evidence of encoding in self-referential effect

Although the self-referential effect was widely supported by several previous studies, there was few event-related potential (ERP) evidence for the encoding mechanism of the self-referential effect. The present study employed ERPs to investigate whether the electrophysiological indices of the encoding processing could predict the retrieval processing in the self-referential paradigm. Behavioral results demonstrated better performance in the self-reference condition than other-reference condition. The N400 and LPP for the subsequent memory effect (the Dm effect) were observed in both self-referential and other-referential trials as shown in the ERP results of the encoding processing. Moreover, the self-referential information had higher amplitudes for subsequently remembered trials. The study also showed correlation between the ERP components in the encoding phase and those in retrieval. These findings suggest that the self-referential effect can be due to more effective encoding process, which in turn predicts better later recall performance.

Review of Abnormal Self-Knowledge in Major Depressive Disorder

Background: Major depressive disorder (MDD) is an affective disorder that is harmful to both physical and mental health. Abnormal self-knowledge, which refers to abnormal judgments about oneself, is a core symptom of depression. However, little research has summarized how and why patients with MDD differ from healthy individuals in terms of self-knowledge. Objective: To gain a better understanding of MDD, we reviewed previous studies that focused on the behavioral and neurological changes of self-knowledge in this illness. Main Findings: On the behavioral level, depressed individuals exhibited negative self-knowledge in an explicit way, while more heterogeneous patterns were reported in implicit results. On the neurological level, depressed individuals, as compared with non-depressed controls, showed abnormal self-referential processing in both early perception and higher cognitive processing phases during the Self-Referential Encoding Task. Furthermore, fMRI studies have reported aberrant activity in the medial prefrontal cortex area for negative self-related items in depression. These results revealed several behavioral features and brain mechanisms underlying abnormal self-knowledge in depression. Future Studies: The neural mechanism of implicit self-knowledge in MDD remains unclear. Future research should examine the importance of others' attitudes on the self-concept of individuals with MDD, and whether abnormal self-views may be modified through cognitive or pharmacological approaches. In addition, differences in abnormal self-knowledge due to genetic variation between depressed and non-depressed populations remain unconfirmed. Importantly, it remains unknown whether abnormal self-knowledge could be used as a specific marker to distinguish healthy individuals from those with MDD. Conclusion: This review extends our understanding of the relationship between self-knowledge and depression by indicating several abnormalities among individuals with MDD and those who are at risk for this illness.

Respect and admiration differentially activate the anterior temporal lobe

Admiration and respect are positive social emotions often experienced when recognizing excellent behavior in another person. Although both strongly rely on appraisal of behavior, admiration focuses on the admirable behavior of a person, while respect focuses on the person as a whole. The evaluation and interpretation of the social behavior of another person are dependent on semantic memory. Social semantic knowledge is represented in the anterior temporal lobe (ATL), and ATL activity is modulated by conceptual details of semantic knowledge. As respect requires evaluation of not only excellent behavior but also of the person as a whole, we hypothesized that the ATL is differentially activated by admiration and respect. To test our hypothesis, we conducted functional magnetic resonance imaging experiments. We presented participants with vignettes describing admirable behavior of fictitious characters and asked them to imagine and report how they would normally feel when encountering the situation described in the vignettes, i.e., admiration or respect and its intensity. A part of the left ATL was more strongly modulated by the intensity of respect than of admiration. Although admiration and respect are often considered to be closely related, our results indicate that the neural substrates underlying these emotions are different.

Cortical thickness and metacognition in cognitively diverse older adults

OBJECTIVE

Metacognition, or the ability to accurately identify, appraise, and monitor one's deficits, is commonly impaired in Alzheimer's disease (AD). Poor metacognition prevents correct appraisal of a range of physical, cognitive, and emotional symptoms and facilitates anosognosia, which has important clinical implications for individuals (e.g., diminished treatment adherence, increased engagement in high-risk situations) and caregivers (e.g., higher burden). However, the neural correlates of metacognitive disturbance are still debated in the literature, partly because of the subjective nature of traditional awareness measures.

METHOD

An objective Feeling of Knowing (FOK) task was used to measure metamemory capacity in a group of cognitively diverse older adults, including 14 with mild to moderate AD and 20 cognitively healthy older adults. The association between three different objective metamemory measures of the FOK task and regional cortical thickness (12 bilateral regions of interest [ROIs] hypothesized to support self-awareness) was analyzed using partial correlations.

RESULTS

Less accurate metamemory at the local and global levels was associated with reduced right posterior cingulate cortical thickness, r = -0.42, p = .02 and reduced right medial prefrontal, r = -0.39, p = .029, respectively.

CONCLUSIONS

To our knowledge, this was the first study to examine metacognition in relation to cortical thickness. Both global and local metamemory functions appear to rely on the integrity of right sided midline regions, known to be important for processing self-referential information. Findings are conceptualized with regard to the Default Mode Network, and also considered in relation to recent findings pointing to the right insula as a region critical for self-awareness. (PsycINFO Database Record

Connectivity between mPFC and PCC predicts post-choice attitude change: The self-referential processing hypothesis of choice justification

Prior research shows that after making a choice, decision makers shift their attitudes in a choice-congruous direction. Although this post-choice attitude change effect is robust, the neural mechanisms underlying it are poorly understood. Here, we tested the hypothesis that decision makers elaborate on their choice in reference to self-knowledge to justify the choice they have made. This self-referential processing of the choice is thought to play a pivotal role in the post-choice attitude change. Twenty-four young American adults made a series of choices. They also rated their attitudes toward the choice options before and after the choices. In support of the current hypothesis, we found that changes in functional connectivity between two putative self-regions (medial prefrontal cortex and posterior cingulate cortex/precuneus]) during the post-choice (vs. pre-choice) rating of the chosen options predicted the post-choice shift of the attitudes toward the chosen options. This finding is the first to suggest that cognitive integration of various self-relevant cognitions is instrumental in fostering post-choice attitude change. Hum Brain Mapp 37:3810-3820, 2016. © 2016 Wiley Periodicals, Inc.

Self-reference enhances relational memory in young and older adults

The present study investigated the influence of self-reference on two kinds of relational memory, internal source memory and associative memory, in young and older adults. Participants encoded object-location word pairs using the strategies of imagination and sentence generation, either with reference to themselves or to a famous other (i.e., George Clooney or Oprah Winfrey). Both young and older adults showed memory benefits in the self-reference conditions compared to other-reference conditions on both tests, and the self-referential effects in older adults were not limited by low memory or executive functioning. These results suggest that self-reference can benefit relational memory in older adults relatively independently of basic memory and executive functions.

Self-Referential Information Alleviates Retrieval Inhibition of Directed Forgetting Effects-An ERP Evidence of Source Memory

Directed forgetting (DF) assists in preventing outdated information from interfering with cognitive processing. Previous studies pointed that self-referential items alleviated DF effects due to the elaboration of encoding processes. However, the retrieval mechanism of this phenomenon remains unknown. Based on the dual-process framework of recognition, the retrieval of self-referential information was involved in familiarity and recollection. Using source memory tasks combined with event-related potential (ERP) recording, our research investigated the retrieval processes of alleviative DF effects elicited by self-referential information. The FN400 (frontal negativity at 400 ms) is a frontal potential at 300–500 ms related to familiarity and the late positive complex (LPC) is a later parietal potential at 500–800 ms related to recollection. The FN400 effects of source memory suggested that familiarity processes were promoted by self-referential effects without the modulation of to-be-forgotten (TBF) instruction. The ERP results of DF effects were involved with LPCs of source memory, which indexed retrieval processing of recollection. The other-referential source memory of TBF instruction caused the absence of LPC effects, while the self-referential source memory of TBF instruction still elicited the significant LPC effects. Therefore, our neural findings suggested that self-referential processing improved both familiarity and recollection. Furthermore, the self-referential processing advantage which was caused by the autobiographical retrieval alleviated retrieval inhibition of DF, supporting that the self-referential source memory alleviated DF effects.

Remembering my friends: Medial prefrontal and hippocampal contributions to the self-reference effect on face memories in a social context

Memories associated with the self are remembered more accurately than those associated with others. The memory enhancement related to the self is known as the self-reference effect (SRE). However, little is known regarding the neural mechanisms underlying the SRE in a social context modulated by social relationships. In the present fMRI study, we investigated encoding-related activation of face memories encoded with the self-referential process in a social context that was manipulated by imagining a person-to-person relationship. Healthy young adults participated in the present study. During encoding, participants encoded unfamiliar target faces by imagining a future friendship with themselves (Self), their friends (Friend), or strangers (Other). During retrieval, participants were presented with target and distracter faces one by one, and they judged whether each face had been previously learned. In the behavioral results, target faces encoded in the Self condition were remembered more accurately than those encoded in the Other condition. fMRI results demonstrated that encoding-related activation in the medial prefrontal cortex (mPFC) was significantly greater in the Self condition than in the Friend or Other conditions. In addition, the generalized psycho-physiological interaction (gPPI) analysis showed that functional connectivity between activation in the hippocampus and the cortical midline structures (CMSs), including the mPFC and precuneus, was significant in the Self but not in the Other condition. These findings suggest that the SRE in a social context could be involved in the interaction between the CMS regions, which are related to the self-referential process, and the hippocampus related to the memory process. Hum Brain Mapp 38:4256-4269, 2017. © 2017 Wiley Periodicals, Inc.

Neural Correlates of Self and Its Interaction With Memory in Healthy Adolescents

Adolescence is marked by the development of personal identity and is associated with structural and functional changes in brain regions associated with Self processing. Yet, little is known about the neural correlates of self-reference processing and self-reference effect in adolescents. This functional magnetic resonance imaging study consists of a self-reference paradigm followed by a recognition test proposed to 30 healthy adolescents aged 13-18 years old. Results showed that the rostral anterior cingulate cortex is specifically involved in self-reference processing and that this specialization develops gradually from 13 to 18 years old. The self-reference effect is associated with increased brain activation changes during encoding, suggesting that the beneficial effect of Self on memory may occur at encoding of self-referential information, rather than at retrieval.

Maternal sensitivity, infant limbic structure volume and functional connectivity: a preliminary study

Mechanisms underlying the profound parental effects on cognitive, emotional and social development in humans remain poorly understood. Studies with nonhuman models suggest variations in parental care affect the limbic system, influential to learning, autobiography and emotional regulation. In some research, nonoptimal care relates to decreases in neurogenesis, although other work suggests early-postnatal social adversity accelerates the maturation of limbic structures associated with emotional learning. We explored whether maternal sensitivity predicts human limbic system development and functional connectivity patterns in a small sample of human infants. When infants were 6 months of age, 20 mother-infant dyads attended a laboratory-based observational session and the infants underwent neuroimaging at the same age. After considering age at imaging, household income and postnatal maternal anxiety, regression analyses demonstrated significant indirect associations between maternal sensitivity and bilateral hippocampal volume at six months, with the majority of associations between sensitivity and the amygdala demonstrating similar indirect, but not significant results. Moreover, functional analyses revealed direct associations between maternal sensitivity and connectivity between the hippocampus and areas important for emotional regulation and socio-emotional functioning. Sensitivity additionally predicted indirect associations between limbic structures and regions related to autobiographical memory. Our volumetric results are consistent with research indicating accelerated limbic development in response to early social adversity, and in combination with our functional results, if replicated in a larger sample, may suggest that subtle, but important, variations in maternal care influence neuroanatomical trajectories important to future cognitive and emotional functioning.

Neural correlates of the self-reference effect: evidence from evaluation and recognition processes

The self-reference effect (SRE) is defined as better recall or recognition performance when the memorized materials refer to the self. Recently, a number of neuroimaging studies using self-referential and other-referential tasks have reported that self- and other-referential judgments basically show greater activation in common brain regions, specifically in the medial prefrontal cortex (MPFC) when compared with nonmentalizing judgments, but that a ventral-to-dorsal gradient in MPFC emerges from a direct comparison between self- and other-judgments. However, most of these previous studies could not provide an adequate explanation for the neural basis of SRE because they did not directly compare brain activation for recognition/recall of the words referenced to the self with another person. Here, we used an event-related functional magnetic resonance imaging (fMRI) that measured brain activity during processing of references to the self and another, and for recognition of self and other referenced words. Results from the fMRI evaluation task indicated greater activation in ventromedial prefrontal cortex (VMPFC) in the self-referential condition. While in the recognition task, VMPFC, posterior cingulate cortex (PCC) and bilateral angular gyrus (AG) showed greater activation when participants correctly recognized self-referenced words versus other-referenced words. These data provide evidence that the self-referenced words evoked greater activation in the self-related region (VMPFC) and memory-related regions (PCC and AG) relative to another person in the retrieval phase, and that the words remained as a stronger memory trace that supports recognition.

Episodic memory and self-reference via semantic autobiographical memory: insights from an fMRI study in younger and older adults

Self-referential processing relies mainly on the medial prefrontal cortex (MPFC) and enhances memory encoding (i.e., Self-Reference Effect, SRE) as it improves the accuracy and richness of remembering in both young and older adults. However, studies on age-related changes in the neural correlates of the SRE on the subjective (i.e., autonoetic consciousness) and the objective (i.e., source memory) qualitative features of episodic memory are lacking. In the present fMRI study, we compared the effects of a self-related (semantic autobiographical memory task) and a non self-related (general semantic memory task) encoding condition on subsequent episodic memory retrieval. We investigated encoding-related activity during each condition in two groups of 19 younger and 16 older adults. Behaviorally, the SRE improved subjective memory performance in both groups but objective memory only in young adults. At the neural level, a direct comparison between self-related and non self-related conditions revealed that SRE mainly activated the cortical midline system, especially the MPFC, in both groups. Additionally, in older adults and regardless of the condition, greater activity was found in a fronto-parietal network. Overall, correlations were noted between source memory performance and activity in the MPFC (irrespective of age) and visual areas (mediated by age). Thus, the present findings expand evidence of the role of the MPFC in self-referential processing in the context of source memory benefit in both young and older adults using incidental encoding via semantic autobiographical memory. However, our finding suggests that its role is less effective in aging.