ABSTRACT
Older adults have difficulties to detect the intentions, thoughts, and feelings of others, indicating an age-associated decline of socio-cognitive abilities that are known as "mentalizing". These deficits in mental state recognition are driven by neurofunctional alterations in brain regions that are implicated in mentalizing, such as the right temporo-parietal junction (rTPJ) and the dorso-medial prefrontal cortex (dmPFC). We tested whether focal transcranial current stimulation (tDCS) of the rTPJ and dmPFC has the potential to eliminate mentalizing deficits in older adults. Mentalizing deficits were assessed with a novel mindreading task that required the recognition of mental states in child faces. Older adults (n = 60) performed worse than younger adults (n = 30) on the mindreading task, indicating age-dependent deficits in mental state recognition. These mentalizing deficits were ameliorated in older adults who received sham-controlled andodal tDCS over the rTPJ (n = 30) but remained unchanged in older adults who received sham-controlled andodal tDCS over the dmPFC (n = 30). We, thus, showed for the first time that anodal tDCS over the rTPJ has the potential to remediate age-dependent mentalizing deficits in a region-specific way. This provides a rationale for exploring stimulation-based interventions targeting mentalizing deficits in older age.
Subject(s)
Prefrontal Cortex , Theory of Mind , Transcranial Direct Current Stimulation , Humans , Transcranial Direct Current Stimulation/methods , Aged , Male , Female , Prefrontal Cortex/physiopathology , Prefrontal Cortex/physiology , Theory of Mind/physiology , Adult , Young Adult , Middle Aged , Aging/physiology , Temporal Lobe/physiopathology , Parietal Lobe/physiopathology , Mentalization/physiology , Aged, 80 and overABSTRACT
OBJECTIVE: Electrode positioning errors contribute to variability of transcranial direct current stimulation (tDCS) effects. We investigated the impact of electrode positioning errors on current flow for tDCS set-ups with different focality. METHODS: Deviations from planned electrode positions were determined using data acquired in an experimental study (N = 240 datasets) that administered conventional and focal tDCS during magnetic resonance imaging (MRI). Comparison of individualized electric field modeling for planned and empirically derived "actual" electrode positions was conducted to quantify the impact of positioning errors on the electric field dose in target regions for tDCS. RESULTS: Planned electrode positions resulted in higher current dose in the target regions for focal compared to conventional montages (7-12%). Deviations from planned positions significantly reduced current flow in the target regions, selectively for focal set-ups (26-30%). Dose reductions were significantly larger for focal compared to conventional set-ups (29-43%). CONCLUSIONS: Precise positioning is crucial when using focal tDCS set-ups to avoid significant reductions of current dose in the intended target regions. SIGNIFICANCE: Our results highlight the urgent need to routinely implement methods for improving electrode positioning, minimization of electrode drift, verification of electrode positions before and/or after tDCS and also to consider positioning errors when investigating dose-response relationships, especially for focal set-ups.
Subject(s)
Electrodes , Transcranial Direct Current Stimulation , Humans , Transcranial Direct Current Stimulation/methods , Male , Female , Adult , Magnetic Resonance Imaging/methods , Young Adult , Brain Mapping/methodsABSTRACT
Loneliness describes a negative experience associated with perceived social disconnection. Despite the clear links between loneliness and mental and physical health, relatively little is known about how loneliness affects cognition. In this study, we tested the effect of loneliness on cognitive distance between the self and others, using a task in which participants completed a surprise memory task for adjectives implicitly encoded in relation to the self, a close friend or a celebrity. We assessed item memory sensitivity, metacognitive sensitivity, metacognitive efficiency and source memory for positive and negative words. In addition, participants reported their trait loneliness and depression. Results revealed an overall self-referential advantage compared with both friend and celebrity encoded items. Likewise, a friend-referential advantage was identified compared to celebrity-encoded items. Individuals who experienced more loneliness showed a greater self-referential bias in comparison to words encoded in relation to a close friend, and a smaller friend-referential bias in comparison to words encoded in relation to celebrity. These findings suggest that loneliness is reflected in a greater cognitive distance between the self and close friends in relation to memory biases. The results have important implications for understanding the social contextual effects on memory and the cognitive ramifications of loneliness.
Subject(s)
Memory, Episodic , Humans , Loneliness , Self Concept , Cognition , LanguageABSTRACT
Body image concern (BIC) is a prevalent issue thought to be exacerbated by social media. In addition to sociocultural factors, cognitive biases may also contribute to BIC. We explore whether cognitive biases in memory for body image-related words, presented in a mock social-media context, are associated with BIC in young adult women. A sample of 150 university students was presented with a series of body image-related comments aimed at either themselves, a close friend, or a celebrity in a recognisable social media context. Afterwards, a surprise memory task was completed that assessed the participant's memory for body image-related words (item memory), their insight (metamemory), and to whom a specific word was directed (source memory). Self-referential biases were identified for both item memory and source memory. Individuals with greater BIC displayed a greater self-referential bias for correctly and incorrectly sourcing negative words to themselves compared with both friend and celebrity. A greater self-referential effect in metacognitive sensitivity was also associated with higher BIC. We provide novel evidence for a cognitive bias in sourcing negative body image-related information to the self in individuals with higher BIC. The results should inform cognitive remediation programmes aimed at treating individuals with body and eating-related disorders.
Subject(s)
Body Image , Social Media , Young Adult , Humans , Female , Body Image/psychology , Friends , Cognition , BiasABSTRACT
BACKGROUND: Trajectories of decline across different socio-cognitive domains in healthy older adults and in pathological aging conditions have not been investigated. This was addressed in the present systematic review and meta-analysis. METHODS: MEDLINE, Web of Science Core Collection, CENTRAL, and PsycInfo were searched for studies investigating social cognition across four domains (Theory of Mind, ToM; emotion recognition, ER; Social-decision making, SD; visual perspective taking, VPT) in healthy older individuals, individuals with subjective and mild cognitive impairment (SCD, MCI) and Alzheimer's disease (AD). Random-effects meta-analyses were conducted. RESULTS: Of 8137 screened studies, 132 studies were included in the review. ToM and ER showed a clear progression of impairment from normal aging to AD. Differential patterns of decline were identified for different types of ToM and ER. CONCLUSION: This systematic review identified progression of impairment of specific socio-cognitive abilities, which is the necessary pre-requisite for developing targeted interventions. We identified a lack of research on socio-cognitive decline in different populations (e.g., middle age, SCD and MCI-subtypes) and domains (SDM, VPT).
Subject(s)
Alzheimer Disease , Cognitive Dysfunction , Healthy Aging , Aged , Cognition , Disease Progression , Humans , Middle AgedABSTRACT
Socio-cognitive abilities and challenges change across the healthy lifespan and are essential for successful human interaction. Identifying effective socio-cognitive training approaches for healthy individuals may prevent development of mental or physical disease and reduced quality of life. A systematic search was conducted in MEDLINE Ovid, Web of Science Core Collection, CENTRAL, and PsycInfo databases. Studies that investigated different socio-cognitive trainings for healthy individuals across the human lifespan assessing effects on theory of mind, emotion recognition, perspective taking, and social decision making were included. A random-effects pairwise meta-analysis was conducted. Risk-of-Bias was assessed using the Cochrane Risk-of-Bias-2-Tool. Twenty-three intervention studies with N = 1835 participants were included in the systematic review; twelve randomized controlled trials in the meta-analysis (N = 875). Socio-cognitive trainings differed regarding duration and content in different age groups, with theory of mind being the domain most frequently trained. Results of the meta-analysis showed that trainings were highly effective for improving theory of mind in children aged 3-5 years (SMD = 2.51 (95%CI: 0.48-4.53)), children aged 7-9 years (SMD = 2.71 (95%CI: - 0.28 to 5.71)), and older adults (SMD = 5.90 (95%CI: 2.77-9.02). Theory of mind training was highly effective in all investigated age-groups for improving theory of mind, yet, more research on transfer effects to other socio-cognitive processes and further investigation of training effects in other socio-cognitive domains (e.g., emotion recognition, visual perspective taking, social decision making) is needed. Identified characteristics of successful socio-cognitive trainings in different age groups may help designing future training studies for other populations.Registration: www.crd.york.ac.uk/PROSPERO/ (ID: CRD42020193297).
Subject(s)
Cognitive Behavioral Therapy , Quality of Life , Aged , Child , Health Status , Humans , Longevity , Randomized Controlled Trials as Topic , Social CognitionABSTRACT
Low-intensity transcranial electrical stimulation (tES), including alternating or direct current stimulation, applies weak electrical stimulation to modulate the activity of brain circuits. Integration of tES with concurrent functional MRI (fMRI) allows for the mapping of neural activity during neuromodulation, supporting causal studies of both brain function and tES effects. Methodological aspects of tES-fMRI studies underpin the results, and reporting them in appropriate detail is required for reproducibility and interpretability. Despite the growing number of published reports, there are no consensus-based checklists for disclosing methodological details of concurrent tES-fMRI studies. The objective of this work was to develop a consensus-based checklist of reporting standards for concurrent tES-fMRI studies to support methodological rigor, transparency and reproducibility (ContES checklist). A two-phase Delphi consensus process was conducted by a steering committee (SC) of 13 members and 49 expert panelists through the International Network of the tES-fMRI Consortium. The process began with a circulation of a preliminary checklist of essential items and additional recommendations, developed by the SC on the basis of a systematic review of 57 concurrent tES-fMRI studies. Contributors were then invited to suggest revisions or additions to the initial checklist. After the revision phase, contributors rated the importance of the 17 essential items and 42 additional recommendations in the final checklist. The state of methodological transparency within the 57 reviewed concurrent tES-fMRI studies was then assessed by using the checklist. Experts refined the checklist through the revision and rating phases, leading to a checklist with three categories of essential items and additional recommendations: (i) technological factors, (ii) safety and noise tests and (iii) methodological factors. The level of reporting of checklist items varied among the 57 concurrent tES-fMRI papers, ranging from 24% to 76%. On average, 53% of checklist items were reported in a given article. In conclusion, use of the ContES checklist is expected to enhance the methodological reporting quality of future concurrent tES-fMRI studies and increase methodological transparency and reproducibility.
Subject(s)
Checklist , Transcranial Direct Current Stimulation , Consensus , Magnetic Resonance Imaging , Reproducibility of ResultsABSTRACT
A prominent theory claims that the right temporoparietal junction (rTPJ) is especially associated with embodied processes relevant to perspective-taking. In the present study, we use high-definition transcranial direct current stimulation to provide evidence that the rTPJ is causally associated with the embodied processes underpinning perspective-taking. Eighty-eight young human adults were stratified to receive either rTPJ or dorsomedial PFC anodal high-definition transcranial direct current stimulation in a sham-controlled, double-blind, repeated-measures design. Perspective-tracking (line-of-sight) and perspective-taking (embodied rotation) were assessed using a visuo-spatial perspective-taking task that required understanding what another person could see or how they see it, respectively. Embodied processing was manipulated by positioning the participant in a manner congruent or incongruent with the orientation of an avatar on the screen. As perspective-taking, but not perspective-tracking, is influenced by bodily position, this allows the investigation of the specific causal role for the rTPJ in embodied processing. Crucially, anodal stimulation to the rTPJ increased the effect of bodily position during perspective-taking, whereas no such effects were identified during perspective-tracking, thereby providing evidence for a causal role for the rTPJ in the embodied component of perspective-taking. Stimulation to the dorsomedial PFC had no effect on perspective-tracking or taking. Therefore, the present study provides support for theories postulating that the rTPJ is causally involved in embodied cognitive processing relevant to social functioning.SIGNIFICANCE STATEMENT The ability to understand another's perspective is a fundamental component of social functioning. Adopting another perspective is thought to involve both embodied and nonembodied processes. The present study used high-definition transcranial direct current stimulation (HD-tDCS) and provided causal evidence that the right temporoparietal junction is involved specifically in the embodied component of perspective-taking. Specifically, HD-tDCS to the right temporoparietal junction, but not another hub of the social brain (dorsomedial PFC), increased the effect of body position during perspective-taking, but not tracking. This is the first causal evidence that HD-tDCS can modulate social embodied processing in a site-specific and task-specific manner.
Subject(s)
Functional Laterality/physiology , Parietal Lobe/physiology , Temporal Lobe/physiology , Visual Perception/physiology , Adolescent , Adult , Cognition , Double-Blind Method , Female , Humans , Male , Movement/physiology , Psychomotor Performance/physiology , Social Perception , Theory of Mind/physiology , Transcranial Direct Current Stimulation , Young AdultABSTRACT
This study investigated effects of multisession transcranial direct-current stimulation on learning and maintenance of novel memory content and scrutinised effects of baseline cognitive status and the role of multi-session tDCS on overnight memory consolidation. In a prospective, randomized, double-blind, parallel-group, sham-tDCS controlled design, 101 healthy young and older adults completed a five-day verbal associative learning paradigm while receiving multisession tDCS to the task-relevant left prefrontal cortex. In older adults, active multisession tDCS enhanced recall performance after each daily training session. Effects were maintained the next morning and during follow-up assessments (one week; three months). In young adults, multisession tDCS significantly increased long-term recall. Unlike previous findings in the motor domain, beneficial effects of multisession tDCS on cognitive learning and memory were notexclusively due to enhanced memory consolidation. Positive stimulation effects were primarily found in participants with lower baseline learning ability, suggesting that multisession tDCS may counteract memory impairment in health and disease.
Subject(s)
Aging/physiology , Memory Consolidation/physiology , Psychomotor Performance/physiology , Transcranial Direct Current Stimulation/methods , Verbal Learning/physiology , Adolescent , Aged , Aging/psychology , Double-Blind Method , Female , Humans , Male , Mental Recall/physiology , Middle Aged , Prefrontal Cortex/physiology , Prospective Studies , Transcranial Direct Current Stimulation/psychology , Young AdultABSTRACT
Rapid emotion processing is an ecologically essential ability for survival in social environments in which threatening or advantageous encounters dynamically and rapidly occur. Efficient emotion recognition is subserved by different processes, depending on one's expectations; however, the underlying functional and structural circuitry is still poorly understood. In this study, we delineate brain networks that subserve fast recognition of emotion in situations either congruent or incongruent with prior expectations. For this purpose, we used multimodal neuroimaging and investigated performance on a dynamic emotion perception task. We show that the extended amygdala structural and functional networks relate to speed of emotion processing under threatening conditions. Specifically, increased microstructure of the right stria terminalis, an amygdala white-matter pathway, was related to faster detection of emotion during actual presentation of anger or after cueing anger. Moreover, functional connectivity of right amygdala with limbic regions was related to faster detection of anger congruent with cue, suggesting selective attention to threat. On the contrary, we found that faster detection of anger incongruent with cue engaged the ventral attention "reorienting" network. Faster detection of happiness, in either expectancy context, engaged a widespread frontotemporal-subcortical functional network. These findings shed light on the functional and structural circuitries that facilitate speed of emotion recognition and, for the first time, elucidate a role for the stria terminalis in human emotion processing.
Subject(s)
Amygdala/diagnostic imaging , Emotions , Motivation , Nerve Net/diagnostic imaging , Parietal Lobe/diagnostic imaging , Septal Nuclei/diagnostic imaging , Temporal Lobe/diagnostic imaging , Adult , Amygdala/physiology , Emotions/physiology , Female , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged , Motivation/physiology , Nerve Net/physiology , Parietal Lobe/physiology , Photic Stimulation/methods , Septal Nuclei/physiology , Temporal Lobe/physiologyABSTRACT
OBJECTIVE: Adaptive cognitive control frequently declines in advanced age. Because high-definition transcranial direct current stimulation (HD-tDCS) of the right dorsolateral prefrontal cortex (DLPFC) improved cognitive control in young adults, we investigated if this montage can also improve cognitive control in older individuals. METHOD: In a double-blind, sham HD-tDCS controlled, cross-over design, 36 older participants received right DLPFC HD-tDCS during a visual flanker task. Conflict adaptation (CA) effects on response time (RT) and error rates (ER) assessed adaptive cognitive control. Biophysical modeling assessed the magnitude and distribution of induced current in older adults. RESULTS: Active HD-tDCS enhanced CA in older adults. However, this positive behavioral effect was limited to CA in ER. Similar to results obtained in healthy young adults, current modeling analysis demonstrated focal current delivery to the DLPFC with sufficient magnitude of the induced current to modulate neural function in older adults. DISCUSSION: This study confirms the effectiveness of HD-tDCS to modulate adaptive cognitive control in advanced age.
Subject(s)
Adaptation, Psychological/physiology , Attention/physiology , Conflict, Psychological , Executive Function/physiology , Prefrontal Cortex/physiology , Psychomotor Performance/physiology , Reaction Time/physiology , Transcranial Direct Current Stimulation , Visual Perception/physiology , Aged , Cross-Over Studies , Double-Blind Method , Female , Humans , Male , Middle Aged , PlacebosABSTRACT
Advanced age is associated with difficulties in social understanding. However, little is known about the underlying cognitive processes. In the present study, healthy young and older adults completed measures of implicit and explicit visual perspective taking (VPT) and measures of executive and social cognition across four experiments. Congruency effects (slower response times or reduced accuracy when scenes were incongruent with the alternate perspective) were identified for the egocentric ("self") and allocentric ("other") conditions of both Level 1 ("line of sight") and Level 2 ("egocentric transformation") explicit VPT. Older adults showed less influence of the alternate perspective during Level 1 VPT, as indexed by fewer errors when the alternate perspective was incongruent. However, during Level 2 VPT, compared with young adults, older adults showed greater influence of the allocentric perspective during egocentric judgments as indexed by slower response times when the scene was incongruent with the allocentric perspective. Older adults were also slower at taking the allocentric perspective in general across both Level 1 and 2 tasks. An implicit VPT effect was identified that was consistent across both age groups. Several VPT measures were associated with executive and social cognition, with different patterns in young and older adults suggesting differing underlying strategies or cognitive processes may partially explain VPT differences between the groups. Difficulties in higher order social tasks may arise from underlying cognitive processes involved in perspective taking and these may be different depending on the requirement to perform an egocentric transformation into the allocentric frame of reference. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Subject(s)
Cognition/physiology , Judgment/physiology , Visual Perception/physiology , Adolescent , Adult , Age Factors , Aged , Executive Function/physiology , Female , Humans , Male , Middle Aged , Reaction Time/physiology , Social Behavior , Young AdultABSTRACT
OBJECTIVE: Executive functions are crucial for adaptive behavior in novel contexts. In healthy aging, these abilities are more sensitive to dysfunction than other cognitive abilities. The effect of aging on initiation, inhibition, and strategy use was investigated via performance on the Hayling Sentence Completion Test. METHOD: The standard Hayling Test and baseline cognitive tests were administered to healthy adults (N = 344), aged 18-89 years (cross-sectional study). Bivariate Pearson's correlations, partial correlations, and regression analyses were used to assess the impact of aging on the components of the Hayling Test. RESULTS: There were significant positive correlations between age and response time for both Initiation and Suppression, and the number of Suppression Errors. Further, older age was negatively associated with strategy use. These findings remained significant after controlling for demographic factors such as education and crystallized intelligence and other cognitive functions sensitive to aging such as fluid intelligence, attention, working memory and semantic and phonemic word fluency. CONCLUSIONS: This study provides clarification of the effect of age on the processes of initiation, inhibition, and strategy generation across the adult lifespan. The focus and analysis of strategy on the Hayling Test provides clinicians with an additional and valuable measure of executive functioning. That is, it provides insight into how older adults may be able to compensate for decline in these processes, and thus maximize quality of life and independence.
Subject(s)
Aging/psychology , Cognition , Executive Function , Inhibition, Psychological , Adolescent , Adult , Aged , Aged, 80 and over , Attention , Cross-Sectional Studies , Female , Humans , Intelligence , Language , Male , Memory, Short-Term , Middle Aged , Neuropsychological Tests , Quality of Life , Reaction Time , Semantics , Young AdultABSTRACT
Impaired emotion perception is a well-established and stable deficit in schizophrenia; however, there is limited knowledge about the underlying aberrant cognitive and brain processes that result in emotion perception deficits. Recent influential work has shown that perceptual deficits in schizophrenia may result from aberrant precision in prior expectations, associated with disrupted activity in frontal regions. In the present study, we investigated the perception of dynamic, multisensory emotion, the influence of prior expectations and the underlying aberrant brain processes in schizophrenia. During a functional Magnetic Resonance Imaging scan, participants completed the Dynamic Emotion Perception task, which induces prior expectations with emotion instruction cues. We delineated neural responses and functional connectivity in whole-brain large-scale networks underlying emotion perception. Compared to healthy individuals, schizophrenia patients had lower accuracy specifically for emotions that were congruent with prior expectations. At the neural level, schizophrenia patients had less engagement of right inferior frontal and parietal regions, as well as right amygdala dysconnectivity during discrimination of emotions congruent with prior expectations. The results indicate that individuals with schizophrenia may have aberrant prior expectations about emotional expressions, associated with under-activity in inferior frontoparietal regions and right amygdala dysconnectivity, which results in impaired perception of emotion.
Subject(s)
Amygdala/physiopathology , Anticipation, Psychological/physiology , Connectome/methods , Emotions/physiology , Nerve Net/physiopathology , Prefrontal Cortex/physiopathology , Schizophrenia/physiopathology , Social Perception , Adult , Amygdala/diagnostic imaging , Facial Expression , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Nerve Net/diagnostic imaging , Parietal Lobe/diagnostic imaging , Parietal Lobe/physiopathology , Prefrontal Cortex/diagnostic imaging , Schizophrenia/diagnostic imagingABSTRACT
Learning associations between words and their referents is crucial for language learning in the developing and adult brain and for language re-learning after neurological injury. Non-invasive transcranial direct current stimulation (tDCS) to the posterior temporo-parietal cortex has been suggested to enhance this process. However, previous studies employed standard tDCS set-ups that induce diffuse current flow in the brain, preventing the attribution of stimulation effects to the target region. This study employed high-definition tDCS (HD-tDCS) that allowed the current flow to be constrained to the temporo-parietal cortex, to clarify its role in novel word learning. In a sham-controlled, double-blind, between-subjects design, 50 healthy adults learned associations between legal non-words and unfamiliar object pictures. Participants were stratified by baseline learning ability on a short version of the learning paradigm and pairwise randomized to active (20 mins; N = 25) or sham (40 seconds; N = 25) HD-tDCS. Accuracy was comparable during the baseline and experimental phases in both HD-tDCS conditions. However, active HD-tDCS resulted in faster retrieval of correct word-picture pairs. Our findings corroborate the critical role of the temporo-parietal cortex in novel word learning, which has implications for current theories of language acquisition.
Subject(s)
Brain/physiology , Parietal Lobe/physiology , Transcranial Direct Current Stimulation/methods , Verbal Learning/physiology , Adult , Double-Blind Method , Female , Functional Laterality , Humans , Male , Young AdultABSTRACT
Transcranial direct current stimulation (tDCS) may be a viable tool to improve motor and cognitive function in advanced age. However, although a number of studies have demonstrated improved cognitive performance in older adults, other studies have failed to show restorative effects. The neural effects of beneficial stimulation response in both age groups is lacking. In the current study, tDCS was administered during simultaneous fMRI in 42 healthy young and older participants. Semantic word generation and motor speech baseline tasks were used to investigate behavioral and neural effects of uni- and bihemispheric motor cortex tDCS in a three-way, crossover, sham tDCS controlled design. Independent components analysis assessed differences in task-related activity between the two age groups and tDCS effects at the network level. We also explored whether laterality of language network organization was effected by tDCS. Behaviorally, both active tDCS conditions significantly improved semantic word retrieval performance in young and older adults and were comparable between groups and stimulation conditions. Network-level tDCS effects were identified in the ventral and dorsal anterior cingulate networks in the combined sample during semantic fluency and motor speech tasks. In addition, a shift toward enhanced left laterality was identified in the older adults for both active stimulation conditions. Thus, tDCS results in common network-level modulations and behavioral improvements for both age groups, with an additional effect of increasing left laterality in older adults.
Subject(s)
Brain Mapping , Motor Cortex/physiology , Neural Pathways/physiology , Psychomotor Performance/physiology , Transcranial Direct Current Stimulation , Adult , Aged , Aging , Analysis of Variance , Electroencephalography , Female , Functional Laterality/physiology , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Male , Memory, Short-Term/physiology , Middle Aged , Motor Cortex/diagnostic imaging , Neural Pathways/diagnostic imaging , Oxygen/blood , Reaction Time/physiology , Semantics , Verbal Learning , Young AdultABSTRACT
The dorsomedial prefrontal cortex (dmPFC) is a key hub of the 'social brain', but little is known about specific processes supported by this region. Using focal high-definition transcranial direct current stimulation (HD-tDCS) and a social cognitive battery with differing demands on self-other processing, we demonstrate specific involvement of the dmPFC in tasks placing high demands on self-other processing. Specifically, excitatory (anodal) HD-tDCS enhanced the integration of external information into the self for explicit higher-order socio-cognitive tasks across cognitive domains; i.e. visual perspective taking (VPT) and episodic memory. These effects were task specific, as no stimulation effects were found for attributing mental states from the eyes or implicit VPT. Inhibitory (cathodal) HD-tDCS had weaker effects in the opposite direction towards reduced integration of external information into the self. We thus demonstrate for the first time a specific and causal role of the dmPFC in integrating higher-order information from others/external source into that of the self across cognitive domains.
Subject(s)
Prefrontal Cortex/physiology , Social Perception , Theory of Mind/physiology , Transcranial Direct Current Stimulation/methods , Adolescent , Adult , Humans , Young AdultABSTRACT
Schizophrenia is associated with mentalizing deficits that impact on social functioning and quality of life. Recently, schizophrenia has been conceptualized as a disorder of neural dysconnectivity and network level analyses offers a means of understanding the underlying deficits leading to mentalizing difficulty. Using an established mentalizing task (The Triangles Task), functional magnetic resonance images (fMRI) were acquired from 19 patients with schizophrenia and 17 age- and sex-matched healthy controls (HCs). Participants were required to watch short animations of two triangles interacting with each other with the interactions either random (no interaction), physical (patterned movement), or mental (intentional movement). Task-based Partial Least Squares (PLS) was used to analyze activation differences and commonalities between the three conditions and the two groups. Seed-based PLS was used to assess functional connectivity with peaks identified in the task-based PLS. Behavioural PLS was then performed using the accuracy from the mental conditions. Patients with schizophrenia performed worse on the mentalizing condition compared to HCs. Task-based PLS revealed one significant latent variable (LV) that explained 42.9% of the variance in the task, with theLV separating the mental condition from the physical and random conditions in patients with schizophrenia, but only the mental from physical in healthy controls. The mental animations were associated with increased modulation of the inferior frontal gyri bilaterally, left superior temporal gyrus, right postcentral gyrus, and left caudate nucleus. The physical/random animations were associated with increased modulation of the right medial frontal gyrus and left superior frontal gyrus. Seed-based PLS identified increased functional connectivity with the left inferior frontal gyrus (liFG) and caudate nucleus in patients with schizophrenia, during the mental and physical interactions, with functional connectivity with the liFG associated with increased performance on the mental animations. The results suggest that mentalizing deficits in schizophrenia may arise due to inefficient social brain networks.
Subject(s)
Brain/physiopathology , Schizophrenia/physiopathology , Schizophrenic Psychology , Theory of Mind/physiology , Brain/diagnostic imaging , Brain Mapping , Female , Humans , Intelligence Tests , Least-Squares Analysis , Magnetic Resonance Imaging , Male , Middle Aged , Motion Perception/physiology , Multivariate Analysis , Neural Pathways/diagnostic imaging , Neural Pathways/physiopathology , Neuropsychological Tests , Schizophrenia/diagnostic imagingABSTRACT
OBJECTIVES: Individuals with schizophrenia have difficulties on measures of executive functioning such as initiation and suppression of responses and strategy development and implementation. The current study thoroughly examines performance on the Hayling Sentence Completion Test (HSCT) in individuals with schizophrenia, introducing novel analyses based on initiation errors and strategy use, and association with lifetime clinical symptoms. METHODS: The HSCT was administered to individuals with schizophrenia (N=77) and age- and sex-matched healthy controls (N=45), along with background cognitive tests. The standard HSCT clinical measures (initiation response time, suppression response time, suppression errors), composite initiation and suppression error scores, and strategy-based responses were calculated. Lifetime clinical symptoms [formal thought disorder (FTD), positive, negative] were calculated using the Lifetime Dimensions of Psychosis Scale. RESULTS: After controlling for baseline cognitive differences, individuals with schizophrenia were significantly impaired on the suppression response time and suppression error scales. For the novel analyses, individuals with schizophrenia produced a greater number of initiation errors and subtly wrong errors, and produced fewer responses indicative of developing an appropriate strategy. Strategy use was negatively correlated with FTD symptoms in individuals with schizophrenia. CONCLUSIONS: The current study provides further evidence for deficits in the initiation and suppression of verbal responses in individuals with schizophrenia. Moreover, an inability to attain a strategy at least partly contributes to increased semantically connected errors when attempting to suppress responses. The association between strategy use and FTD points to the involvement of executive deficits in disorganized speech in schizophrenia. (JINS, 2016, 22, 735-743).
Subject(s)
Executive Function/physiology , Schizophrenia/physiopathology , Verbal Behavior/physiology , Adult , Female , Humans , Male , Middle AgedABSTRACT
Social interactions require the ability to rapidly perceive emotion from various incoming dynamic, multisensory cues. Prior expectations reduce incoming emotional information and direct attention to cues that are aligned with what is expected. Studies to date have investigated the prior expectancy effect using static emotional images, despite the fact that dynamic stimuli would represent greater ecological validity. The objective of the study was to create a novel functional magnetic resonance imaging (fMRI) paradigm to examine the influence of prior expectations on naturalistic emotion perception. For this purpose, we developed a dynamic emotion perception task, which consisted of audio-visual videos that carry emotional information congruent or incongruent with prior expectations. The results show that emotional congruency was associated with activity in prefrontal regions, amygdala, and putamen, whereas emotional incongruency was associated with activity in temporoparietal junction and mid-cingulate gyrus. Supported by the behavioural results, our findings suggest that prior expectations are reinforced after repeated experience and learning, whereas unexpected emotions may rely on fast change detection processes. The results from the current study are compatible with the notion that the ability to automatically detect unexpected changes in complex dynamic environments allows for adaptive behaviours in potentially advantageous or threatening situations.