RESUMO
Social exclusion contributes to alcohol consumption, whereas the development of alcohol dependence (AD) can in turn lead to the social exclusion of people with AD. Previous research observed altered neural responses to experimentally induced social exclusion (i.e., Cyberball game) in patients with AD. In addition, inflammation has been associated with both social behaviours and AD. Our study aimed to investigate the dynamic behavioural response and the inflammatory effects of social exclusion in male patients with a history of AD. To this end, we analysed dynamic changes in ball tossing during a partial exclusion Cyberball game and the cytokine interleukin (IL)-1b in saliva in 31 male patients who had a history of AD and 29 gender-matched healthy controls without AD. Participants were included in the first 2 min of the Cyberball game and then excluded by one of the two co-players in the proceeding 5 min. Saliva was collected three times: one before and two after the Cyberball game. Across groups, participants passed the ball more often to the excluder during the partial exclusion period. Analysis using piece-wise linear mixed models showed that patients rapidly increased ball tosses to the excluder upon exclusion, which lasted to the late response phase, whereas the early behavioural response to exclusion took longer for controls. There was no significant change of salivary IL-1b level to exclusion in either patients or controls. The results indicate a distinct dynamic behavioural response to social exclusion in male patients with a history of AD.
Assuntos
Alcoolismo , Humanos , Masculino , Isolamento Social , Comportamento SocialRESUMO
BACKGROUND: Extraintestinal symptoms are common in inflammatory bowel diseases (IBD) and include depression and fatigue. These are highly prevalent especially in active disease, potentially due to inflammation-mediated changes in the microbiota-gut-brain axis. The aim of this study was to investigate the associations between structural and functional microbiota characteristics and severity of fatigue and depressive symptoms in patients with active IBD. METHODS: We included clinical data of 62 prospectively enrolled patients with IBD in an active disease state. Patients supplied stool samples and completed the questionnaires regarding depression and fatigue symptoms. Based on taxonomic and functional metagenomic profiles of faecal gut microbiota, we used Bayesian statistics to investigate the associative networks and triangle motifs between bacterial genera, functional modules and symptom severity of self-reported fatigue and depression. RESULTS: Associations with moderate to strong evidence were found for 3 genera (Odoribacter, Anaerotruncus and Alistipes) and 3 functional modules (pectin, glycosaminoglycan and central carbohydrate metabolism) with regard to depression and for 4 genera (Intestinimonas, Anaerotruncus, Eubacterium and Clostridiales g.i.s) and 2 functional modules implicating amino acid and central carbohydrate metabolism with regard to fatigue. CONCLUSIONS: This study provides the first evidence of association triplets between microbiota composition, function and extraintestinal symptoms in active IBD. Depression and fatigue were associated with lower abundances of short-chain fatty acid producers and distinct pathways implicating glycan, carbohydrate and amino acid metabolism. Our results suggest that microbiota-directed therapeutic approaches may reduce fatigue and depression in IBD and should be investigated in future research.
Assuntos
Doenças Inflamatórias Intestinais , Microbiota , Aminoácidos , Teorema de Bayes , Depressão , Fadiga , Fezes/microbiologia , Glicosaminoglicanos , Humanos , Metagenômica , PectinasRESUMO
Alterations of the brain extracellular matrix (ECM) can perturb the structure and function of brain networks like the hippocampus, a key region in human memory that is commonly affected in psychiatric disorders. Here, we investigated the potential effects of a genome-wide psychiatric risk variant in the NCAN gene encoding the ECM proteoglycan neurocan (rs1064395) on memory performance, hippocampal function and cortical morphology in young, healthy volunteers. We assessed verbal memory performance in two cohorts (N = 572, 302) and found reduced recall performance in risk allele (A) carriers across both cohorts. In 117 participants, we performed functional magnetic resonance imaging using a novelty-encoding task with visual scenes. Risk allele carriers showed higher false alarm rates during recognition, accompanied by inefficiently increased left hippocampal activation. To assess effects of rs1064395 on brain morphology, we performed voxel-based morphometry in 420 participants from four independent cohorts and found lower grey matter density in the ventrolateral and rostral prefrontal cortex of risk allele carriers. In silico eQTL analysis revealed that rs1064395 SNP is linked not only to increased prefrontal expression of the NCAN gene itself, but also of the neighbouring HAPLN4 gene, suggesting a more complex effect of the SNP on ECM composition. Our results suggest that the NCAN rs1064395 A allele is associated with lower hippocampus-dependent memory function, variation of prefrontal cortex structure and ECM composition. Considering the well-documented hippocampal and prefrontal dysfunction in bipolar disorder and schizophrenia, our results may reflect an intermediate phenotype by which NCAN rs1064395 contributes to disease risk.
Assuntos
Transtorno Bipolar , Hipocampo , Neurocam/genética , Esquizofrenia , Mapeamento Encefálico , Proteoglicanas de Sulfatos de Condroitina/genética , Hipocampo/diagnóstico por imagem , Hipocampo/fisiologia , Humanos , Lectinas Tipo C/genética , Imageamento por Ressonância Magnética , Memória , Proteínas do Tecido Nervoso/genéticaRESUMO
The level of functioning of individuals with autism spectrum disorder (ASD) varies widely. To better understand the neurobiological mechanism associated with high-functioning ASD, we studied the rare case of a female patient with an exceptional professional career in the highly competitive academic field of Mathematics. According to the Research Domain Criteria (RDoC) approach, which proposes to describe the basic dimensions of functioning by integrating different levels of information, we conducted four fMRI experiments targeting the (1) social processes domain (Theory of mind (ToM) and face matching), (2) positive valence domain (reward processing), and (3) cognitive domain (N-back). Patient's data were compared to data of 14 healthy controls (HC). Additionally, we assessed the subjective experience of our case during the experiments. The patient showed increased response times during face matching and achieved a higher total gain in the Reward task, whereas her performance in N-back and ToM was similar to HC. Her brain function differed mainly in the positive valence and cognitive domains. During reward processing, she showed reduced activity in a left-hemispheric frontal network and cortical midline structures but increased connectivity within this network. During the working memory task patients' brain activity and connectivity in left-hemispheric temporo-frontal regions were elevated. In the ToM task, activity in posterior cingulate cortex and temporo-parietal junction was reduced. We suggest that the high level of functioning in our patient is rather related to the effects in brain connectivity than to local cortical information processing and that subjective report provides a fruitful framework for interpretation.
Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Cognição , Feminino , Humanos , Imageamento por Ressonância MagnéticaRESUMO
BACKGROUND: Limbic-cortical imbalance is an established model for the neurobiology of major depressive disorder (MDD), but imaging genetics studies have been contradicting regarding potential risk and resilience mechanisms. Here, we re-assessed previously reported limbic-cortical alterations between MDD relatives and controls in combination with a newly acquired sample of MDD patients and controls, to disentangle pathology, risk, and resilience. METHODS: We analyzed functional magnetic resonance imaging data and negative affectivity (NA) of MDD patients (n = 48), unaffected first-degree relatives of MDD patients (n = 49) and controls (n = 109) who performed a faces matching task. Brain response and task-dependent amygdala functional connectivity (FC) were compared between groups and assessed for associations with NA. RESULTS: Groups did not differ in task-related brain activation but activation in the superior frontal gyrus (SFG) was inversely correlated with NA in patients and controls. Pathology was associated with task-independent decreases of amygdala FC with regions of the default mode network (DMN) and decreased amygdala FC with the medial frontal gyrus during faces matching, potentially reflecting a task-independent DMN predominance and a limbic-cortical disintegration during faces processing in MDD. Risk was associated with task-independent decreases of amygdala-FC with fronto-parietal regions and reduced faces-associated amygdala-fusiform gyrus FC. Resilience corresponded to task-independent increases in amygdala FC with the perigenual anterior cingulate cortex (pgACC) and increased FC between amygdala, pgACC, and SFG during faces matching. CONCLUSION: Our results encourage a refinement of the limbic-cortical imbalance model of depression. The validity of proposed risk and resilience markers needs to be tested in prospective studies. Further limitations are discussed.
Assuntos
Tonsila do Cerebelo/fisiopatologia , Transtorno Depressivo Maior/fisiopatologia , Transtorno Depressivo Maior/psicologia , Emoções/fisiologia , Resiliência Psicológica , Adulto , Biomarcadores , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Fatores de Risco , Adulto JovemRESUMO
Social exclusion (ostracism) is a major psychosocial factor contributing to the development and persistence of psychiatric disorders and is also related to their social stigma. However, its specific role in different disorders is not evident, and comprehensive social psychology research on ostracism has rather focused on healthy individuals and less on psychiatric patients. Here, we systematically review experimental studies investigating psychological and physiological reactions to ostracism in different responses of psychiatric disorders. Moreover, we propose a theoretical model of the interplay between psychiatric symptoms and ostracism. A systematic MEDLINE and PsycINFO search was conducted including 52 relevant studies in various disorders (some of which evaluated more than one disorder): borderline personality disorder (21 studies); major depressive disorder (11 studies); anxiety (7 studies); autism spectrum disorder (6 studies); schizophrenia (6 studies); substance use disorders (4 studies); and eating disorders (2 studies). Psychological and physiological effects of ostracism were assessed with various experimental paradigms: e.g., virtual real-time interactions (Cyberball), social feedback and imagined scenarios. We critically review the main results of these studies and propose the overall concept of a vicious cycle where psychiatric symptoms increase the chance of being ostracized, and ostracism consolidates or even aggravates psychopathology. However, the specificity and stability of reactions to ostracism, their neurobiological underpinnings, determinants, and moderators (e.g., attachment style, childhood trauma, and rejection sensitivity) remain elusive.
Assuntos
Transtornos Mentais , Isolamento Social , Humanos , Transtornos Mentais/etiologia , Transtornos Mentais/fisiopatologia , Transtornos Mentais/psicologiaRESUMO
Based on numerous findings of an abnormal laterality in schizophrenia disorder, we hypothesized that handedness and lateral preferences may affect the age at onset in schizophrenia patients. Two samples of schizophrenia patients, the first a sample of 34 right-handers and 42 left-handers and a replication set of 84 right-handers, were examined with regard to age at onset considering handedness and the four Luria's signs (arm folding, hand clasping, familial sinistrality and eye dominance) as well as gender. The association between these parameters and age at onset was investigated by means of multiple regression analysis. Our analyses revealed that right-handers with right arm folding and left-handers with left arm folding showed an early age at onset, while in the late age at onset the opposite preferences prevailed. Apart from arm folding, signs of ambilaterality, i.e., left eye dominance in right-handers and familial sinistrality in left-handers were additional predictors for an early age at onset. Remarkably, all observations found in the first right-handed sample were confirmed in the right-handed replication set. We conclude that among the many different factors specific lateral preferences should also be considered in assessing patients who are at risk of psychosis.
Assuntos
Lateralidade Funcional , Esquizofrenia , Idade de Início , Braço , Mãos , Humanos , Esquizofrenia/epidemiologia , Esquizofrenia/genéticaRESUMO
What effect does social exclusion have on the perception of the other person and how can this effect be recorded with the help of experimental methods? Answering this question can provide psychologists, sociologists and clinicians with valuable insights for understanding as well as for concrete interaction with the people or groups concerned. Social groups that are particularly frequently confronted with social exclusion include people with mental illness, migrants and ethnic minorities. In this article we present the results of an experimental preliminary study on healthy volunteers in which we used a modified version of the cyberball paradigm to investigate the effects of social exclusion on the spontaneous assessment of personality traits such as attractiveness, trustworthiness, aggressiveness and dominance. The results of our study show that these effects can be quantified with the help of the cyberball paradigm and that the perception of the other person changes after a relatively short period of social interaction depending on their valence. Against the background of these findings, we discuss the potential of this paradigm to investigate social factors that can play a role in the development of mental illness in migrants and discuss the particularities to be considered in prospective application in the risk groups mentioned above.
Assuntos
Emigrantes e Imigrantes/psicologia , Relações Interpessoais , Transtornos Mentais/psicologia , Personalidade , Distância Psicológica , HumanosRESUMO
Activation of parietal cortex structures like the precuneus is commonly observed during explicit memory retrieval, but the role of parietal cortices in encoding has only recently been appreciated and is still poorly understood. Considering the importance of the precuneus in human visual attention and imagery, we aimed to assess a potential role for the precuneus in the encoding of visuospatial representations into long-term memory. We therefore investigated the acquisition of constant versus repeatedly shuffled configurations of icons on background images over five subsequent days in 32 young, healthy volunteers. Functional magnetic resonance imaging was conducted on Days 1, 2, and 5, and persistent memory traces were assessed by a delayed memory test after another 5 days. Constant compared to shuffled configurations were associated with significant improvement of position recognition from Day 1 to 5 and better delayed memory performance. Bilateral dorsal precuneus activations separated constant from shuffled configurations from Day 2 onward, and coactivation of the precuneus and hippocampus dissociated recognized and forgotten configurations, irrespective of condition. Furthermore, learning of constant configurations elicited increased functional coupling of the precuneus with dorsal and ventral visual stream structures. Our results identify the precuneus as a key brain structure in the acquisition of detailed visuospatial information by orchestrating a parieto-occipito-temporal network.
Assuntos
Aprendizagem por Associação/fisiologia , Memória/fisiologia , Lobo Parietal/fisiologia , Percepção Espacial/fisiologia , Percepção Visual/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Hipocampo/diagnóstico por imagem , Hipocampo/fisiologia , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Lobo Parietal/diagnóstico por imagem , Estimulação Luminosa , Desempenho Psicomotor , Adulto JovemRESUMO
In the domain of working memory (WM), a sigmoid-shaped relationship between WM load and brain activation patterns has been demonstrated in younger adults. It has been suggested that age-related alterations of this pattern are associated with changes in neural efficiency and capacity. At the same time, WM training studies have shown that some older adults are able to increase their WM performance through training. In this study, functional magnetic resonance imaging during an n-back WM task at different WM load levels was applied to compare blood oxygen level-dependent (BOLD) responses between younger and older participants and to predict gains in WM performance after a subsequent 12-session WM training procedure in older adults. We show that increased neural efficiency and capacity, as reflected by more "youth-like" brain response patterns in regions of interest of the frontoparietal WM network, were associated with better behavioral training outcome beyond the effects of age, sex, education, gray matter volume, and baseline WM performance. Furthermore, at low difficulty levels, decreases in BOLD response were found after WM training. Results indicate that both neural efficiency (i.e., decreased activation at comparable performance levels) and capacity (i.e., increasing activation with increasing WM load) of a WM-related network predict plasticity of the WM system, whereas WM training may specifically increase neural efficiency in older adults.
Assuntos
Envelhecimento/fisiologia , Encéfalo/fisiologia , Memória de Curto Prazo/fisiologia , Adulto , Idoso , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Adulto JovemRESUMO
The perception of control over the environment constitutes a fundamental biological adaptive mechanism, especially during development. Previous studies comparing an active choice condition with a passive no-choice condition showed that the neural basis of this mechanism is associated with increased activity within the striatum and the prefrontal cortex. In the current study, we aimed to investigate whether subjective belief of control in an uncertain gambling situation induces elevated activation in a cortico-striatal network. We investigated 79 adolescents (age range: 13-16years) during reward anticipation with a slot machine task using functional magnetic resonance imaging. We assessed post-experimentally whether the participants experienced a subjective illusion of control on winning or losing in this task that was objectively not given. Nineteen adolescents experienced an illusion of control during slot machine gambling. This illusion of control group showed an increased neural activity during reward anticipation within a cortico-striatal network including ventral striatum (VS) as well as right inferior frontal gyrus (rIFG) relative to the group reporting no illusion of control. The rIFG activity was inversely associated with impulsivity in the no illusion of control group. The subjective belief about control led to an elevated ventral striatal activity, which is known to be involved in the processing of reward. This finding strengthens the notion that subjectively perceived control, not necessarily the objective presence of control, affects striatal reward-related processing.
Assuntos
Desenvolvimento do Adolescente/fisiologia , Antecipação Psicológica/fisiologia , Mapeamento Encefálico/métodos , Ilusões/fisiologia , Controle Interno-Externo , Córtex Pré-Frontal/fisiologia , Recompensa , Estriado Ventral/fisiologia , Adolescente , Feminino , Jogo de Azar , Jogos Experimentais , Humanos , Comportamento Impulsivo/fisiologia , Imageamento por Ressonância Magnética , MasculinoRESUMO
In alcohol dependence, individual prediction of treatment outcome based on neuroimaging endophenotypes can help to tailor individual therapeutic offers to patients depending on their relapse risk. We built a prediction model for prospective relapse of alcohol-dependent patients that combines structural and functional brain images derived from an experiment in which 46 subjects were exposed to alcohol-related cues. The patient group had been subdivided post hoc regarding relapse behavior defined as a consumption of more than 60 g alcohol for male or more than 40 g alcohol for female patients on one occasion during the 3-month assessment period (16 abstainers and 30 relapsers). Naïve Bayes, support vector machines and learning vector quantization were used to infer prediction models for relapse based on the mean and maximum values of gray matter volume and brain responses on alcohol-related cues within a priori defined regions of interest. Model performance was estimated by leave-one-out cross-validation. Learning vector quantization yielded the model with the highest balanced accuracy (79.4 percent, p < 0.0001; 90 percent sensitivity, 68.8 percent specificity). The most informative individual predictors were functional brain activation features in the right and left ventral tegmental areas and the right ventral striatum, as well as gray matter volume features in left orbitofrontal cortex and right medial prefrontal cortex. In contrast, the best pure clinical model reached only chance-level accuracy (61.3 percent). Our results indicate that an individual prediction of future relapse from imaging measurement outperforms prediction from clinical measurements. The approach may help to target specific interventions at different risk groups.
Assuntos
Alcoolismo/patologia , Encefalopatias/patologia , Adulto , Alcoolismo/fisiopatologia , Encefalopatias/fisiopatologia , Diagnóstico Precoce , Feminino , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Recidiva , Sensibilidade e EspecificidadeRESUMO
Pathological gambling (PG) shares clinical characteristics such as craving and loss of control with substance use disorders and is thus considered a behavioral addiction. While functional alterations in the mesolimbic reward system have been correlated with craving and relapse in substance use disorders, only a few studies have examined this brain circuit in PG, and no direct comparison has been conducted so far. Thus, we investigated the neuronal correlates of reward processing in PG in contrast to alcohol-dependent (AD) patients and healthy subjects. Eighteen PG patients, 15 AD patients and 17 controls were investigated with a monetary incentive delay task, in which visual cues predict the consequence (monetary gain, avoidance of loss, none) of a fast response to a subsequent target stimulus. Functional magnetic resonance imaging data were analyzed to account for possible confounding factors such as local gray matter volume. Activity in the right ventral striatum during loss anticipation was increased in PG patients compared with controls and AD patients. Moreover, PG patients showed decreased activation in the right ventral striatum and right medial prefrontal cortex during successful loss avoidance compared with controls, which was inversely associated with severity of gambling behavior. Thus, despite neurobiological similarities to substance use disorders in reward processing, as reported by previous studies, we found relevant differences with respect to the anticipation of loss as well as its avoidance (negative reinforcement), which further contributes to the understanding of PG.
Assuntos
Jogo de Azar/psicologia , Recompensa , Adulto , Alcoolismo/patologia , Alcoolismo/fisiopatologia , Alcoolismo/psicologia , Antecipação Psicológica , Encefalopatias/patologia , Encefalopatias/fisiopatologia , Mapeamento Encefálico , Estudos de Casos e Controles , Desvalorização pelo Atraso/fisiologia , Feminino , Jogo de Azar/patologia , Jogo de Azar/fisiopatologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Tamanho do Órgão , Córtex Pré-Frontal/patologia , Córtex Pré-Frontal/fisiopatologia , Estriado Ventral/patologia , Estriado Ventral/fisiopatologiaRESUMO
Coordinated triadic interactions, involving oneself, another person, and an external object, are considered a uniquely human skill. However, the exact mechanisms underlying the ability to engage in such social interactions remain hitherto unknown. We used functional neuroimaging to investigate the neural signature of triadic interactions. For this purpose, participants viewed pictures of objects in a 3T functional magnetic resonance imaging scanner and were asked whether they could imagine this object in a social interaction with another person. We also aimed to dissociate this process from, as well as to find commonalities with, purely self-referential or other-referential processing. In all trial-types, we found activations in core mentalizing brain areas (medial prefrontal cortex, posterior cingulate cortex, precuneus and temporoparietal junction). Furthermore, triadic engagements, but not self-referential or other-referential processing, were associated with activations in classical mirror neuron areas (inferior frontal gyrus and inferior parietal lobe). Finally, mentalizing networks showed a strong functional connectivity with mirror neuron areas exclusively during triadic engagements. These results suggest that the imagined interaction of two agents is processed in a more complex neural social cognitive network than purely self- or other-referential considerations.
Assuntos
Encéfalo/fisiologia , Imaginação/fisiologia , Relações Interpessoais , Teoria da Mente/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Neurônios-Espelho/fisiologia , Rede Nervosa/fisiologia , Adulto JovemRESUMO
Importance: In the last 25 years, functional magnetic resonance imaging drug cue reactivity (FDCR) studies have characterized some core aspects in the neurobiology of drug addiction. However, no FDCR-derived biomarkers have been approved for treatment development or clinical adoption. Traversing this translational gap requires a systematic assessment of the FDCR literature evidence, its heterogeneity, and an evaluation of possible clinical uses of FDCR-derived biomarkers. Objective: To summarize the state of the field of FDCR, assess their potential for biomarker development, and outline a clear process for biomarker qualification to guide future research and validation efforts. Evidence Review: The PubMed and Medline databases were searched for every original FDCR investigation published from database inception until December 2022. Collected data covered study design, participant characteristics, FDCR task design, and whether each study provided evidence that might potentially help develop susceptibility, diagnostic, response, prognostic, predictive, or severity biomarkers for 1 or more addictive disorders. Findings: There were 415 FDCR studies published between 1998 and 2022. Most focused on nicotine (122 [29.6%]), alcohol (120 [29.2%]), or cocaine (46 [11.1%]), and most used visual cues (354 [85.3%]). Together, these studies recruited 19â¯311 participants, including 13â¯812 individuals with past or current substance use disorders. Most studies could potentially support biomarker development, including diagnostic (143 [32.7%]), treatment response (141 [32.3%]), severity (84 [19.2%]), prognostic (30 [6.9%]), predictive (25 [5.7%]), monitoring (12 [2.7%]), and susceptibility (2 [0.5%]) biomarkers. A total of 155 interventional studies used FDCR, mostly to investigate pharmacological (67 [43.2%]) or cognitive/behavioral (51 [32.9%]) interventions; 141 studies used FDCR as a response measure, of which 125 (88.7%) reported significant interventional FDCR alterations; and 25 studies used FDCR as an intervention outcome predictor, with 24 (96%) finding significant associations between FDCR markers and treatment outcomes. Conclusions and Relevance: Based on this systematic review and the proposed biomarker development framework, there is a pathway for the development and regulatory qualification of FDCR-based biomarkers of addiction and recovery. Further validation could support the use of FDCR-derived measures, potentially accelerating treatment development and improving diagnostic, prognostic, and predictive clinical judgments.
Assuntos
Biomarcadores , Sinais (Psicologia) , Imageamento por Ressonância Magnética , Transtornos Relacionados ao Uso de Substâncias , Humanos , Transtornos Relacionados ao Uso de Substâncias/fisiopatologia , Transtornos Relacionados ao Uso de Substâncias/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Encéfalo/metabolismo , Neuroimagem FuncionalRESUMO
The neural mechanisms behind cognitive deficits in schizophrenia still remain unclear. Functional neuroimaging studies on working memory (WM) yielded inconsistent results, suggesting task performance as a moderating variable of prefrontal activation. Beyond regional specific activation, disordered integration of brain regions was supposed as a critical pathophysiological mechanism of cognitive deficits in schizophrenia. Here, we first hypothesized that prefrontal activation implicated in WM depends primarily on task performance and therefore stratified participants into performance subgroups. Second, in line with the dysconnectivity hypothesis, we asked whether connectivity in the prefrontal-parietal network underlying WM is altered in all patients. We used functional magnetic resonance imaging in human subjects (41 schizophrenia patients, 42 healthy controls) and dynamic causal modeling to examine effective connectivity during a WM task. In line with our first hypothesis, we found that prefrontal activation was differentially modulated by task performance: there was a significant task by group by performance interaction revealing an increase of activation with performance in patients and a decrease with performance in controls. Beyond that, we show for the first time that WM-dependent effective connectivity from prefrontal to parietal cortex is reduced in all schizophrenia patients. This finding was independent of performance. In conclusion, our results are in line with the highly influential hypothesis that the relationship between WM performance and prefrontal activation follows an inverted U-shaped function. Moreover, this study in a large sample of patients reveals a mechanism underlying prefrontal inefficiency and cognitive deficits in schizophrenia, thereby providing direct experimental evidence for the dysconnectivity hypothesis.
Assuntos
Transtornos da Memória/fisiopatologia , Transtornos da Memória/psicologia , Memória de Curto Prazo/fisiologia , Lobo Parietal/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Esquizofrenia/fisiopatologia , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Transtornos da Memória/diagnóstico , Pessoa de Meia-Idade , Modelos Neurológicos , Vias Neurais/fisiopatologia , Lobo Parietal/citologia , Córtex Pré-Frontal/citologia , Esquizofrenia/diagnóstico , Psicologia do Esquizofrênico , Adulto JovemRESUMO
New episodic memory traces represent a record of the ongoing neocortical processing engaged during memory formation (encoding). Thus, during encoding, deep (semantic) processing typically establishes more distinctive and retrievable memory traces than does shallow (perceptual) processing, as assessed by later episodic memory tests. By contrast, the hippocampus appears to play a processing-independent role in encoding, because hippocampal lesions impair encoding regardless of level of processing. Here, we clarified the neural relationship between processing and encoding by examining hippocampal-cortical connectivity during deep and shallow encoding. Participants studied words during functional magnetic resonance imaging and freely recalled these words after distraction. Deep study processing led to better recall than shallow study processing. For both levels of processing, successful encoding elicited activations of bilateral hippocampus and left prefrontal cortex, and increased functional connectivity between left hippocampus and bilateral medial prefrontal, cingulate and extrastriate cortices. Successful encoding during deep processing was additionally associated with increased functional connectivity between left hippocampus and bilateral ventrolateral prefrontal cortex and right temporoparietal junction. In the shallow encoding condition, on the other hand, pronounced functional connectivity increases were observed between the right hippocampus and the frontoparietal attention network activated during shallow study processing. Our results further specify how the hippocampus coordinates recording of ongoing neocortical activity into long-term memory, and begin to provide a neural explanation for the typical advantage of deep over shallow study processing for later episodic memory.
Assuntos
Córtex Cerebral/fisiologia , Hipocampo/fisiologia , Memória Episódica , Vias Neurais/fisiologia , Adolescente , Adulto , Algoritmos , Análise de Variância , Mapeamento Encefálico , Interpretação Estatística de Dados , Feminino , Lateralidade Funcional/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Rememoração Mental/fisiologia , Modelos Estatísticos , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Psicofisiologia , Tempo de Reação/fisiologia , Leitura , Adulto JovemRESUMO
Fluid intelligence represents the capacity for flexible problem solving and rapid behavioral adaptation. Rewards drive flexible behavioral adaptation, in part via a teaching signal expressed as reward prediction errors in the ventral striatum, which has been associated with phasic dopamine release in animal studies. We examined a sample of 28 healthy male adults using multimodal imaging and biological parametric mapping with (1) functional magnetic resonance imaging during a reversal learning task and (2) in a subsample of 17 subjects also with positron emission tomography using 6-[(18) F]fluoro-L-DOPA to assess dopamine synthesis capacity. Fluid intelligence was measured using a battery of nine standard neuropsychological tests. Ventral striatal BOLD correlates of reward prediction errors were positively correlated with fluid intelligence and, in the right ventral striatum, also inversely correlated with dopamine synthesis capacity (FDOPA K inapp). When exploring aspects of fluid intelligence, we observed that prediction error signaling correlates with complex attention and reasoning. These findings indicate that individual differences in the capacity for flexible problem solving relate to ventral striatal activation during reward-related learning, which in turn proved to be inversely associated with ventral striatal dopamine synthesis capacity.
Assuntos
Gânglios da Base/metabolismo , Mapeamento Encefálico , Dopamina/biossíntese , Inteligência/fisiologia , Adulto , Gânglios da Base/diagnóstico por imagem , Mapeamento Encefálico/métodos , Humanos , Testes de Inteligência , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Resolução de Problemas/fisiologia , Adulto JovemRESUMO
Despite a rising social relevance of pathological computer game playing, it remains unclear whether the neurobiological basis of this addiction-like behavioral disorder and substance-related addiction are comparable. In substance-related addiction, attentional bias and cue reactivity are often observed. We conducted a functional magnetic resonance study using a dot probe paradigm with short-presentation (attentional bias) and long-presentation (cue reactivity) trials in eight male pathological computer game players (PCGPs) and nine healthy controls (HCs). Computer game-related and neutral computer-generated pictures, as well as pictures from the International Affective Picture System with positive and neutral valence, served as stimuli. PCGPs showed an attentional bias toward both game-related and affective stimuli with positive valence. In contrast, HCs showed no attentional bias effect at all. PCGPs showed stronger brain responses in short-presentation trials compared with HCs in medial prefrontal cortex (MPFC) and anterior cingulate gyrus and in long-presentation trials in lingual gyrus. In an exploratory post hoc functional connectivity analyses, for long-presentation trials, connectivity strength was higher between right inferior frontal gyrus, which was associated with inhibition processing in previous studies, and cue reactivity-related regions (left orbitofrontal cortex and ventral striatum) in PCGPs. We observed behavioral and neural effects in PCGPs, which are comparable with those found in substance-related addiction. However, cue-related brain responses were depending on duration of cue presentation. Together with the connectivity result, these findings suggest that top-down inhibitory processes might suppress the cue reactivity-related neural activity in long-presentation trials.
Assuntos
Atenção/fisiologia , Comportamento Aditivo/fisiopatologia , Córtex Cerebral/fisiopatologia , Sinais (Psicologia) , Inibição Psicológica , Jogos de Vídeo/psicologia , Adulto , Análise de Variância , Mapeamento Encefálico , Estudos de Casos e Controles , Hipocampo/fisiopatologia , Humanos , Processamento de Imagem Assistida por Computador , Internet , Modelos Lineares , Imageamento por Ressonância Magnética/métodos , Masculino , Testes Neuropsicológicos , Estimulação Luminosa/métodos , Tempo de Reação/fisiologia , Fatores de Tempo , Adulto JovemRESUMO
Social exclusion is a critical event for mental health. Patients with interpersonal dysfunction, e.g., with borderline personality disorder (BPD) or persistent depressive disorder (PDD), are particularly vulnerable, often based on their experiences of early adversity in life. The etiological pathways from childhood maltreatment (CM) to current behavior during social exclusion are still underexplored. This cross-diagnostic study investigated the relationship between self-reported CM and behavioral reaction to social exclusion in an experimental paradigm (Cyberball). Data from 140 subjects including patients with BPD and PDD as well as healthy controls were analyzed. The effect of CM (Childhood Trauma Questionnaire, CTQ) on behavior to social exclusion during Cyberball (ball tossing behavior) was analyzed including rejection sensitivity (RS) as a mediator. In the whole sample, the CTQ score (B = -.004, p < .05) as well as the emotional neglect subscore (B = -.016, p < .01) were associated with a reduced ball tossing behavior towards the excluder. There were no significant indirect effects involving RS. These current findings support the relationship between CM and an altered interpersonal response in critical interpersonal situations. Larger cohorts with multidimensional data in social domains are warranted to further investigate the link between CM and current interpersonal dysfunction.