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1.
Comput Psychiatr ; 5(1): 102-118, 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-35656356

RESUMO

Investing in strangers in a socio-economic exchange is risky, as we may be uncertain whether they will reciprocate. Nevertheless, the potential rewards for cooperating can be great. Here, we used a cross sectional sample (n = 784) to study how the challenges of cooperation versus defection are negotiated across an important period of the lifespan: from adolescence to young adulthood (ages 14 to 25). We quantified social behaviour using a multi round investor-trustee task, phenotyping individuals using a validated model whose parameters characterise patterns of real exchange and constitute latent social characteristics. We found highly significant differences in investment behaviour according to age, sex, socio-economic status and IQ. Consistent with the literature, we showed an overall trend towards higher trust from adolescence to young adulthood but, in a novel finding, we characterized key cognitive mechanisms explaining this, especially regarding socio-economic risk aversion. Males showed lower risk-aversion, associated with greater investments. We also found that inequality aversion was higher in females and, in a novel relation, that socio-economic deprivation was associated with more risk averse play.

2.
Neuropathol Appl Neurobiol ; 47(1): 3-16, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32935873

RESUMO

There is increasing evidence that patients with Coronavirus disease 19 (COVID-19) present with neurological and psychiatric symptoms. Anosmia, hypogeusia, headache, nausea and altered consciousness are commonly described, although there are emerging clinical reports of more serious and specific conditions such as acute cerebrovascular accident, encephalitis and demyelinating disease. Whether these presentations are directly due to viral invasion of the central nervous system (CNS) or caused by indirect mechanisms has yet to be established. Neuropathological examination of brain tissue at autopsy will be essential to establish the neuro-invasive potential of the SARS-CoV-2 virus but, to date, there have been few detailed studies. The pathological changes in the brain probably represent a combination of direct cytopathic effects mediated by SARS-CoV-2 replication or indirect effects due to respiratory failure, injurious cytokine reaction, reduced immune response and cerebrovascular accidents induced by viral infection. Further large-scale molecular and cellular investigations are warranted to clarify the neuropathological correlates of the neurological and psychiatric features seen clinically in COVID-19. In this review, we summarize the current reports of neuropathological examination in COVID-19 patients, in addition to our own experience, and discuss their contribution to the understanding of CNS involvement in this disease.


Assuntos
COVID-19/complicações , COVID-19/patologia , Doenças do Sistema Nervoso/patologia , Doenças do Sistema Nervoso/virologia , Feminino , Humanos , Masculino , SARS-CoV-2
3.
Sci Rep ; 10(1): 3402, 2020 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-32099008

RESUMO

Patterns of functional interactions across distributed brain regions are suggested to provide a scaffold for the conscious processing of information, with marked topological alterations observed in loss of consciousness. However, establishing a firm link between macro-scale brain network organisation and conscious cognition requires direct investigations into neuropsychologically-relevant architectural modifications across systematic reductions in consciousness. Here we assessed both global and regional disturbances to brain graphs in a group of healthy participants across baseline resting state fMRI as well as two distinct levels of propofol-induced sedation. We found a persistent modular architecture, yet significant reorganisation of brain hubs that formed parts of a wider rich-club collective. Furthermore, the reduction in the strength of rich-club connectivity was significantly associated with the participants' performance in a semantic judgment task, indicating the importance of this higher-order topological feature for conscious cognition. These results highlight a remarkable interplay between global and regional properties of brain functional interactions in supporting conscious cognition that is relevant to our understanding of clinical disorders of consciousness.


Assuntos
Encéfalo/fisiopatologia , Estado de Consciência , Rede Nervosa/fisiopatologia , Vias Neurais/fisiopatologia , Adulto , Encéfalo/diagnóstico por imagem , Sedação Consciente , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Propofol/administração & dosagem , Inconsciência/fisiopatologia
4.
Cereb Cortex ; 28(12): 4440-4453, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30307494

RESUMO

With increasing attention on the developmental causes of neuropsychiatric disorders, appropriate animal models are crucial to identifying causes and assessing potential interventions. The common marmoset is an ideal model as it has sophisticated social/emotional behavior, reaching adulthood within 2 years of birth. Magnetic resonance imaging was used in an accelerated longitudinal cohort (n = 41; aged 3-27 months; scanned 2-7 times over 2 years). Splines were used to model nonlinear trajectories of grey matter volume development in 53 cortical areas and 16 subcortical nuclei. Generally, volumes increased before puberty, peaked, and declined into adulthood. We identified 3 milestones of grey matter development: I) age at peak volume; II) age at onset of volume decline; and III) age at maximum rate of volume decline. These milestones differentiated growth trajectories of primary sensory/motor cortical areas from those of association cortex but also revealed distinct trajectories between association cortices. Cluster analysis of trajectories showed that prefrontal cortex was the most heterogenous of association regions, comprising areas with distinct milestones and developmental trajectories. These results highlight the potential of high-field structural MRI to define the dynamics of primate brain development and importantly to identify when specific prefrontal circuits may be most vulnerable to environmental impact.


Assuntos
Encéfalo/anatomia & histologia , Encéfalo/crescimento & desenvolvimento , Animais , Callithrix , Feminino , Substância Cinzenta/anatomia & histologia , Substância Cinzenta/crescimento & desenvolvimento , Imageamento por Ressonância Magnética , Masculino , Modelos Neurológicos
5.
Transl Psychiatry ; 7(8): e1208, 2017 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-28809860

RESUMO

Evidence on systemic inflammation as a risk factor for future depression is inconsistent, possibly due to a lack of regard for persistency of exposure. We examined whether being inflamed on multiple occasions increases risk of new depressive symptoms using prospective data from a population-based sample of adults aged 50 years or older (the English Longitudinal Study of Ageing). Participants with less than four of eight depressive symptoms in 2004/05 and 2008/09 based on the Eight-item Centre for Epidemiologic Studies Depression scale were analysed. The number of occasions with C-reactive protein ⩾3 mg l-1 over the same initial assessments (1 vs 0 occasion, and 2 vs 0 occasions) was examined in relation to change in depressive symptoms between 2008/09 and 2012/13 and odds of developing depressive symptomology (having more than or equal to four of eight symptoms) in 2012/13. In multivariable-adjusted regression models (n=2068), participants who were inflamed on 1 vs 0 occasion showed no increase in depressive symptoms nor raised odds of developing depressive symptomology; those inflamed on 2 vs 0 occasions showed a 0.10 (95% confidence intervals (CIs)=-0.07, 0.28) symptom increase and 1.60 (95% CI=1.00, 2.55) times higher odds. In further analyses, 2 vs 0 occasions of inflammation were associated with increased odds of developing depressive symptoms among women (odds ratio (OR)=2.75, 95% CI=1.53, 4.95), but not among men (OR=0.70, 95% CI=0.29, 1.68); P-for-sex interaction=0.035. In this cohort study of older adults, repeated but not transient exposure to systemic inflammation was associated with increased risk of future depressive symptoms among women; this subgroup finding requires confirmation of validity.


Assuntos
Depressão/complicações , Inflamação/complicações , Idoso , Estudos de Coortes , Depressão/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Estudos Prospectivos , Escalas de Graduação Psiquiátrica , Fatores de Risco
6.
Cereb Cortex ; 27(8): 4267-4276, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28633299

RESUMO

Background: While autism and attention-deficit/hyperactivity disorder (ADHD) are considered distinct conditions from a diagnostic perspective, clinically they share some phenotypic features and have high comorbidity. Regardless, most studies have focused on only one condition, with considerable heterogeneity in their results. Taking a dual-condition approach might help elucidate shared and distinct neural characteristics. Method: Graph theory was used to analyse topological properties of structural covariance networks across both conditions and relative to a neurotypical (NT; n = 87) group using data from the ABIDE (autism; n = 62) and ADHD-200 datasets (ADHD; n = 69). Regional cortical thickness was used to construct the structural covariance networks. This was analysed in a theoretical framework examining potential differences in long and short-range connectivity, with a specific focus on relation between central graph measures and cortical thickness. Results: We found convergence between autism and ADHD, where both conditions show an overall decrease in CT covariance with increased Euclidean distance between centroids compared with a NT population. The 2 conditions also show divergence. Namely, there is less modular overlap between the 2 conditions than there is between each condition and the NT group. The ADHD group also showed reduced cortical thickness and lower degree in hub regions than the autism group. Lastly, the ADHD group also showed reduced wiring costs compared with the autism groups. Conclusions: Our results indicate a need for taking an integrated approach when considering highly comorbid conditions such as autism and ADHD. Furthermore, autism and ADHD both showed alterations in the relation between inter-regional covariance and centroid distance, where both groups show a steeper decline in covariance as a function of distance. The 2 groups also diverge on modular organization, cortical thickness of hub regions and wiring cost of the covariance network. Thus, on some network features the groups are distinct, yet on others there is convergence.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico por imagem , Transtorno Autístico/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Transtorno do Deficit de Atenção com Hiperatividade/patologia , Transtorno Autístico/patologia , Encéfalo/patologia , Criança , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/diagnóstico por imagem , Vias Neurais/patologia , Tamanho do Órgão
7.
Psychopharmacology (Berl) ; 234(15): 2289-2297, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28551713

RESUMO

RATIONALE: Biased attention towards drug-related cues and reduced inhibitory control over the regulation of drug-intake characterize drug addiction. The noradrenaline system has been critically implicated in both attentional and response inhibitory processes and is directly affected by drugs such as cocaine. OBJECTIVES: We examined the potentially beneficial effects of the noradrenaline reuptake inhibitor atomoxetine in improving cognitive control during two tasks that used cocaine- and non-cocaine-related stimuli. METHODS: A double-blind, placebo-controlled, and cross-over psycho-pharmacological design was employed. A single oral dose of atomoxetine (40 mg) was administered to 28 cocaine-dependent individuals (CDIs) and 28 healthy controls. All participants performed a pictorial attentional bias task involving both cocaine- and non-cocaine-related pictures as well as a verbal go/no-go task composed of cocaine- and food-related words. RESULTS: As expected, CDIs showed attentional bias to cocaine-related cues whilst controls did not. More importantly, however, atomoxetine, relative to placebo, significantly attenuated attentional bias in CDIs (F 26 = 6.73, P = 0.01). During the go/no-go task, there was a treatment × trial × group interaction, although this finding only showed a trend towards statistical significance (F 26 = 3.38, P = 0.07). CONCLUSIONS: Our findings suggest that atomoxetine reduces attentional bias to drug-related cues in CDIs. This may result from atomoxetine's modulation of the balance between tonic/phasic activity in the locus coeruleus and the possibly parallel enhancement of noradrenergic neurotransmission within the prefrontal cortex. Studying how cognitive enhancers such as atomoxetine influence key neurocognitive indices in cocaine addiction may help to develop reliable biomarkers for patient stratification in future clinical trials.


Assuntos
Inibidores da Captação Adrenérgica/administração & dosagem , Cloridrato de Atomoxetina/administração & dosagem , Viés de Atenção/efeitos dos fármacos , Transtornos Relacionados ao Uso de Cocaína/psicologia , Sinais (Psicologia) , Administração Oral , Inibidores da Captação Adrenérgica/sangue , Adulto , Cloridrato de Atomoxetina/sangue , Atenção/efeitos dos fármacos , Atenção/fisiologia , Viés de Atenção/fisiologia , Transtornos Relacionados ao Uso de Cocaína/sangue , Transtornos Relacionados ao Uso de Cocaína/tratamento farmacológico , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa/métodos , Desempenho Psicomotor/efeitos dos fármacos , Desempenho Psicomotor/fisiologia , Resultado do Tratamento
8.
Psychol Med ; 47(13): 2312-2322, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28397612

RESUMO

BACKGROUND: Adolescence is a key time period for the emergence of psychosocial and mental health difficulties. To promote adolescent adaptive ('resilient') psychosocial functioning (PSF), appropriate conceptualisation and quantification of such functioning and its predictors is a crucial first step. Here, we quantify resilient functioning as the degree to which an individual functions better or worse than expected given their self-reported childhood family experiences, and relate this to adolescent family and friendship support. METHOD: We used Principal Component and regression analyses to investigate the relationship between childhood family experiences and PSF (psychiatric symptomatology, personality traits and mental wellbeing) in healthy adolescents (the Neuroscience in Psychiatry Network; N = 2389; ages 14-24). Residuals from the relation between childhood family experiences and PSF reflect resilient functioning; the degree to which an individual is functioning better, or worse, than expected given their childhood family experiences. Next, we relate family and friendship support with resilient functioning both cross-sectionally and 1 year later. RESULTS: Friendship and family support were positive predictors of immediate resilient PSF, with friendship support being the strongest predictor. However, whereas friendship support was a significant positive predictor of later resilient functioning, family support had a negative relationship with later resilient PSF. CONCLUSIONS: We show that friendship support, but not family support, is an important positive predictor of both immediate and later resilient PSF in adolescence and early adulthood. Interventions that promote the skills needed to acquire and sustain adolescent friendships may be crucial in increasing adolescent resilient PSF.


Assuntos
Família/psicologia , Amigos/psicologia , Transtornos Mentais/psicologia , Poder Familiar/psicologia , Satisfação Pessoal , Personalidade/fisiologia , Resiliência Psicológica , Apoio Social , Adolescente , Adulto , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Masculino , Transtornos Mentais/etiologia , Adulto Jovem
9.
Psychol Med ; 46(12): 2561-9, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27345441

RESUMO

BACKGROUND: Little is known about time perception, its putative role as cognitive endophenotype, and its neuroanatomical underpinnings in adults with attention deficit hyperactivity disorder (ADHD). METHOD: Twenty adults with ADHD, 20 unaffected first-degree relatives and 20 typically developing controls matched for age and gender undertook structural magnetic resonance imaging scans. Voxel-based morphometry with DARTEL was performed to obtain regional grey-matter volumes. Temporal processing was investigated as a putative cognitive endophenotype using a temporal reproduction paradigm. General linear modelling was employed to examine the relationship between temporal reproduction performances and grey-matter volumes. RESULTS: ADHD participants were impaired in temporal reproduction and unaffected first-degree relatives performed in between their ADHD probands and typically developing controls. Increased grey-matter volume in the cerebellum was associated with poorer temporal reproduction performance. CONCLUSIONS: Adults with ADHD are impaired in time reproduction. Performances of the unaffected first-degree relatives are in between ADHD relatives and controls, suggesting that time reproduction might be a cognitive endophenotype for adult ADHD. The cerebellum is involved in time reproduction and might play a role in driving time performances.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/patologia , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Substância Cinzenta/patologia , Percepção do Tempo/fisiologia , Adulto , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico por imagem , Endofenótipos , Feminino , Substância Cinzenta/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Núcleo Familiar , Adulto Jovem
10.
Cereb Cortex ; 26(7): 3297-309, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27130663

RESUMO

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition, which is accompanied by differences in gray matter neuroanatomy and white matter connectivity. However, it is unknown whether these differences are linked or reflect independent aetiologies. Using a multimodal neuroimaging approach, we therefore examined 51 male adults with ASD and 48 neurotypical controls to investigate the relationship between gray matter local gyrification (lGI) and white matter diffusivity in associated fiber tracts. First, ASD individuals had a significant increase in gyrification around the left pre- and post-central gyrus. Second, white matter fiber tracts originating and/or terminating in the cluster of increased lGI had a significant increase in axial diffusivity. This increase in diffusivity was predominantly observed in tracts in close proximity to the cortical sheet. Last, we demonstrate that the increase in lGI was significantly correlated with increased diffusivity of short tracts. This relationship was not significantly modulated by a main effect of group (i.e., ASD), which was more closely associated with gray matter gyrification than white matter diffusivity. Our findings suggest that differences in gray matter neuroanatomy and white matter connectivity are closely linked, and may reflect common rather than distinct aetiological pathways.


Assuntos
Transtorno do Espectro Autista/diagnóstico por imagem , Córtex Cerebral/diagnóstico por imagem , Substância Cinzenta/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adolescente , Adulto , Imagem de Tensor de Difusão , Humanos , Imageamento Tridimensional , Inteligência , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/diagnóstico por imagem , Tamanho do Órgão , Reconhecimento Automatizado de Padrão , Adulto Jovem
11.
Int J Obes (Lond) ; 40(7): 1177-82, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27089992

RESUMO

BACKGROUND: Although obesity is associated with structural changes in brain grey matter, findings have been inconsistent and the precise nature of these changes is unclear. Inconsistencies may partly be due to the use of different volumetric morphometry methods, and the inclusion of participants with comorbidities that exert independent effects on brain structure. The latter concern is particularly critical when sample sizes are modest. The purpose of the current study was to examine the relationship between cortical grey matter and body mass index (BMI), in healthy participants, excluding confounding comorbidities and using a large sample size. SUBJECTS: A total of 202 self-reported healthy volunteers were studied using surface-based morphometry, which permits the measurement of cortical thickness, surface area and cortical folding, independent of each other. RESULTS: Although increasing BMI was not associated with global cortical changes, a more precise, region-based analysis revealed significant thinning of the cortex in two areas: left lateral occipital cortex (LOC) and right ventromedial prefrontal cortex (vmPFC). An analogous region-based analysis failed to find an association between BMI and regional surface area or folding. Participants' age was also found to be negatively associated with cortical thickness of several brain regions; however, there was no overlap between the age- and BMI-related effects on cortical thinning. CONCLUSIONS: Our data suggest that the key effect of increasing BMI on cortical grey matter is a focal thinning in the left LOC and right vmPFC. Consistent implications of the latter region in reward valuation, and goal control of decision and action suggest a possible shift in these processes with increasing BMI.


Assuntos
Índice de Massa Corporal , Mapeamento Encefálico , Substância Cinzenta/patologia , Adolescente , Adulto , Imagem de Tensor de Difusão , Comportamento Alimentar , Feminino , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/metabolismo , Voluntários Saudáveis , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/patologia , Sobrepeso/complicações , Sobrepeso/patologia , Sobrepeso/fisiopatologia , Adulto Jovem
12.
Psychol Med ; 46(5): 897-907, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26809184

RESUMO

Abnormal brain connectivity or network dysfunction has been suggested as a paradigm to understand several psychiatric disorders. We here review the use of novel meta-analytic approaches in neuroscience that go beyond a summary description of existing results by applying network analysis methods to previously published studies and/or publicly accessible databases. We define this strategy of combining connectivity with other brain characteristics as 'meta-connectomics'. For example, we show how network analysis of task-based neuroimaging studies has been used to infer functional co-activation from primary data on regional activations. This approach has been able to relate cognition to functional network topology, demonstrating that the brain is composed of cognitively specialized functional subnetworks or modules, linked by a rich club of cognitively generalized regions that mediate many inter-modular connections. Another major application of meta-connectomics has been efforts to link meta-analytic maps of disorder-related abnormalities or MRI 'lesions' to the complex topology of the normative connectome. This work has highlighted the general importance of network hubs as hotspots for concentration of cortical grey-matter deficits in schizophrenia, Alzheimer's disease and other disorders. Finally, we show how by incorporating cellular and transcriptional data on individual nodes with network models of the connectome, studies have begun to elucidate the microscopic mechanisms underpinning the macroscopic organization of whole-brain networks. We argue that meta-connectomics is an exciting field, providing robust and integrative insights into brain organization that will likely play an important future role in consolidating network models of psychiatric disorders.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Conectoma/métodos , Substância Cinzenta/fisiopatologia , Rede Nervosa/fisiopatologia , Vias Neurais/fisiopatologia , Esquizofrenia/diagnóstico por imagem , Cognição , Humanos , Imageamento por Ressonância Magnética/métodos , Neuroimagem
13.
Neuroimage ; 125: 544-555, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26596551

RESUMO

A growing body of literature suggests that changes in consciousness are reflected in specific connectivity patterns of the brain as obtained from resting state fMRI (rs-fMRI). As simultaneous electroencephalography (EEG) is often unavailable, decoding of potentially confounding sleep patterns from rs-fMRI itself might be useful and improve data interpretation. Linear support vector machine classifiers were trained on combined rs-fMRI/EEG recordings from 25 subjects to separate wakefulness (S0) from non-rapid eye movement (NREM) sleep stages 1 (S1), 2 (S2), slow wave sleep (SW) and all three sleep stages combined (SX). Classifier performance was quantified by a leave-one-subject-out cross-validation (LOSO-CV) and on an independent validation dataset comprising 19 subjects. Results demonstrated excellent performance with areas under the receiver operating characteristics curve (AUCs) close to 1.0 for the discrimination of sleep from wakefulness (S0|SX), S0|S1, S0|S2 and S0|SW, and good to excellent performance for the classification between sleep stages (S1|S2:~0.9; S1|SW:~1.0; S2|SW:~0.8). Application windows of fMRI data from about 70 s were found as minimum to provide reliable classifications. Discrimination patterns pointed to subcortical-cortical connectivity and within-occipital lobe reorganization of connectivity as strongest carriers of discriminative information. In conclusion, we report that functional connectivity analysis allows valid classification of NREM sleep stages.


Assuntos
Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética/métodos , Fases do Sono/fisiologia , Máquina de Vetores de Suporte , Vigília/fisiologia , Encéfalo/fisiologia , Eletroencefalografia , Feminino , Humanos , Masculino , Descanso , Adulto Jovem
14.
Neuroimage Clin ; 9: 140-52, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26413477

RESUMO

Endophenotypes are heritable and quantifiable markers that may assist in the identification of the complex genetic underpinnings of psychiatric conditions. Here we examined global hypoconnectivity as an endophenotype of autism spectrum conditions (ASCs). We studied well-matched groups of adolescent males with autism, genetically-related siblings of individuals with autism, and typically-developing control participants. We parcellated the brain into 258 regions and used complex-network analysis to detect a robust hypoconnectivity endophenotype in our participant group. We observed that whole-brain functional connectivity was highest in controls, intermediate in siblings, and lowest in ASC, in task and rest conditions. We identified additional, local endophenotype effects in specific networks including the visual processing and default mode networks. Our analyses are the first to show that whole-brain functional hypoconnectivity is an endophenotype of autism in adolescence, and may thus underlie the heritable similarities seen in adolescents with ASC and their relatives.


Assuntos
Transtorno do Espectro Autista/patologia , Transtorno do Espectro Autista/fisiopatologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Adolescente , Mapeamento Encefálico , Endofenótipos , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Irmãos
15.
Transl Psychiatry ; 5: e582, 2015 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-26080317

RESUMO

Though stimulant drugs such as cocaine are considered highly addictive, some individuals report recreational use over long periods without developing dependence. Difficulties in response inhibition have been hypothesized to contribute to dependence, but previous studies investigating response inhibition in recreational cocaine users have reported conflicting results. Performance on a stop-signal task was examined in 24 recreational cocaine users and 32 healthy non-drug using control participants matched for age, gender and verbal intelligence during functional magnetic resonance imaging scanning. The two groups were further matched on traumatic childhood histories and the absence of family histories of addiction. Results revealed that recreational cocaine users did not significantly differ from controls on any index of task performance, including response execution and stop-signal reaction time, with the latter averaging 198 ms in both groups. Functional magnetic resonance imaging analyses indicated that, compared with controls, stopping in the recreational users was associated with increased activation in the pre-supplementary motor area but not the right inferior frontal cortex. Thus, findings imply intact response inhibition abilities in recreational cocaine users, though the distinct pattern of accompanying activation suggests increased recruitment of brain areas implicated in response inhibition. This increased recruitment could be attributed to compensatory mechanisms that enable preserved cognitive control in this group, possibly relating to their hypothetical resilience to stimulant drug dependence. Such overactivation, alternatively, may be attributable to prolonged cocaine use leading to neuroplastic adaptations.


Assuntos
Transtornos Relacionados ao Uso de Cocaína/psicologia , Função Executiva/fisiologia , Inibição Psicológica , Córtex Motor/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Adulto , Encéfalo/fisiopatologia , Estudos de Casos e Controles , Estimulantes do Sistema Nervoso Central , Cocaína , Transtornos Relacionados ao Uso de Cocaína/fisiopatologia , Feminino , Lobo Frontal/fisiopatologia , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Tempo de Reação , Análise e Desempenho de Tarefas , Adulto Jovem
16.
Transl Psychiatry ; 5: e540, 2015 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-25826115

RESUMO

Psychotic disorders such as schizophrenia are biologically complex and carry huge population morbidity due to their prevalence, persistence and associated disability. Defined by features such as delusions and hallucinations, they involve cognitive dysfunction and neurotransmitter dysregulations that appear mostly to involve the dopaminergic and glutamatergic systems. A number of genetic and environmental factors are associated with these disorders but it has been difficult to identify the biological pathways underlying the principal symptoms. The endophenotype concept of stable, heritable traits that form a mechanistic link between genes and an overt expression of the disorder has potential to reduce the complexity of psychiatric phenotypes. In this study, we used a genetically sensitive design with individuals with a first episode of psychosis, their non-affected first-degree relatives and non-related healthy controls. Metabolomic analysis was combined with neurocognitive assessment to identify multilevel endophenotypic patterns: one concerned reaction times during the performance of cognitive and emotional tests that have previously been associated with the glutamate neurotransmission system, the other involved metabolites involved directly and indirectly in the co-activation of the N-methyl-D-aspartate receptor, a major receptor of the glutamate system. These cognitive and metabolic endophenotypes may comprise a single construct, such that genetically mediated dysfunction in the glutamate system may be responsible for delays in response to cognitive and emotional functions in psychotic disorders. This focus on glutamatergic neurotransmission should guide drug discovery and experimental medicine programmes in schizophrenia and related disorders.


Assuntos
Endofenótipos/sangue , Aminoácidos Excitatórios/sangue , Predisposição Genética para Doença/genética , Transtornos Psicóticos/sangue , Transtornos Psicóticos/genética , Transmissão Sináptica/genética , Adulto , Análise de Variância , Cromatografia Líquida , Feminino , Ácido Glutâmico/sangue , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Espectrometria de Massas , Metabolômica , Testes Neuropsicológicos , Análise de Componente Principal , Transtornos Psicóticos/fisiopatologia , Tempo de Reação , Receptores de N-Metil-D-Aspartato/sangue , Transmissão Sináptica/fisiologia , Adulto Jovem
17.
Mol Psychiatry ; 20(3): 345-52, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24840709

RESUMO

Why do we repeat choices that we know are bad for us? Decision making is characterized by the parallel engagement of two distinct systems, goal-directed and habitual, thought to arise from two computational learning mechanisms, model-based and model-free. The habitual system is a candidate source of pathological fixedness. Using a decision task that measures the contribution to learning of either mechanism, we show a bias towards model-free (habit) acquisition in disorders involving both natural (binge eating) and artificial (methamphetamine) rewards, and obsessive-compulsive disorder. This favoring of model-free learning may underlie the repetitive behaviors that ultimately dominate in these disorders. Further, we show that the habit formation bias is associated with lower gray matter volumes in caudate and medial orbitofrontal cortex. Our findings suggest that the dysfunction in a common neurocomputational mechanism may underlie diverse disorders involving compulsion.


Assuntos
Viés , Hábitos , Aprendizagem/fisiologia , Transtorno Obsessivo-Compulsivo/fisiopatologia , Adulto , Algoritmos , Encéfalo/patologia , Estudos de Casos e Controles , Comportamento de Escolha , Simulação por Computador , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/patologia , Obesidade/psicologia , Transtorno Obsessivo-Compulsivo/etiologia , Transtorno Obsessivo-Compulsivo/patologia , Análise de Regressão , Recompensa , Transtornos Relacionados ao Uso de Substâncias/complicações , Transtornos Relacionados ao Uso de Substâncias/patologia , Transtornos Relacionados ao Uso de Substâncias/psicologia , Inquéritos e Questionários , Adulto Jovem
18.
Psychol Med ; 44(15): 3215-27, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25065819

RESUMO

BACKGROUND: Mentalizing deficits are a hallmark of the autism spectrum condition (ASC) and a potential endophenotype for atypical social cognition in ASC. Differences in performance and neural activation on the 'Reading the Mind in the Eyes' task (the Eyes task) have been identified in individuals with ASC in previous studies. METHOD: Performance on the Eyes task along with the associated neural activation was examined in adolescents with ASC (n = 50), their unaffected siblings (n = 40) and typically developing controls (n = 40). Based on prior literature that males and females with ASC display different cognitive and associated neural characteristics, analyses were stratified by sex. Three strategies were applied to test for endophenotypes at the level of neural activation: (1) identifying and locating conjunctions of ASC-control and sibling-control differences; (2) examining whether the sibling group is comparable to the ASC or intermediate between the ASC and control groups; and (3) examining spatial overlaps between ASC-control and sibling-control differences across multiple thresholds. RESULTS: Impaired behavioural performance on the Eyes task was observed in males with ASC compared to controls, but only at trend level in females; and no difference in performance was identified between sibling and same-sex control groups in both sexes. Neural activation showed a substantial endophenotype effect in the female groups but this was only modest in the male groups. CONCLUSIONS: Behavioural impairment on complex emotion recognition associated with mental state attribution is a phenotypic, rather than an endophenotypic, marker of ASC. However, the neural response during the Eyes task is a potential endophenotypic marker for ASC, particularly in females.


Assuntos
Encéfalo/fisiopatologia , Transtornos Globais do Desenvolvimento Infantil/fisiopatologia , Expressão Facial , Irmãos , Teoria da Mente/fisiologia , Adolescente , Endofenótipos , Olho , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Fatores Sexuais
19.
Transl Psychiatry ; 3: e257, 2013 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-23673468

RESUMO

Cognitive and neural abnormalities are known to accompany chronic drug abuse, with impairments in cognition and changes in cortical structure seen in stimulant-dependent individuals. However, premorbid differences have also been observed in the brains and behavior of individuals at risk for substance abuse, before they develop dependence. Endophenotype research has emerged as a useful method for assessing preclinical traits that may be risk factors for pathology by studying patient populations and their undiagnosed first-degree relatives. This study used the color-word Stroop task to assess executive functioning in stimulant-dependent individuals, their unaffected biological siblings and unrelated healthy control volunteers using a functional magnetic resonance imaging paradigm. Both the stimulant-dependent and sibling participants demonstrated impairments in cognitive control and processing speed on the task, registering significantly longer response latencies. However, the two groups generated very different neural responses, with the sibling participants exhibiting a significant decrease in activation in the inferior frontal gyrus compared with both stimulant-dependent individuals and control participants. Both target groups also demonstrated a decrease in hemispheric laterality throughout the task, exhibiting a disproportionate increase in right hemispheric activation, which was associated with their behavioral inefficiencies. These findings not only suggest a possible risk factor for stimulant abuse of poor inhibitory control and cortical inefficiency but they also demonstrate possible adaptations in the brains of stimulant users.


Assuntos
Transtornos Cognitivos/complicações , Lobo Frontal/fisiopatologia , Transtornos Relacionados ao Uso de Substâncias/complicações , Adulto , Transtornos Cognitivos/fisiopatologia , Transtornos Cognitivos/psicologia , Função Executiva/fisiologia , Feminino , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Irmãos , Teste de Stroop , Transtornos Relacionados ao Uso de Substâncias/fisiopatologia , Transtornos Relacionados ao Uso de Substâncias/psicologia
20.
Neurosci Biobehav Rev ; 37(10 Pt 1): 2438-44, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23563062

RESUMO

There are many new advances in neuroscience and mental health which should lead to a greater understanding of the neurobiological dysfunction in neuropsychiatric disorders and new developments for early, effective treatments. To do this, a biomarker approach combining genetic, neuroimaging, cognitive and other biological measures is needed. The aim of this article is to highlight novel approaches for pharmacological and non-pharmacological treatment development. This article suggests approaches that can be taken in the future including novel mechanisms with preliminary clinical validation to provide a toolbox for mechanistic studies and also examples of translation and back-translation. The review also emphasizes the need for clinician-scientists to be trained in a novel way in order to equip them with the conceptual and experimental techniques required, and emphasizes the need for private-public partnership and pre-competitive knowledge exchange. This should lead the way for important new holistic treatment developments to improve cognition, functional outcome and well-being of people with neuropsychiatric disorders.


Assuntos
Descoberta de Drogas/métodos , Transtornos Mentais/tratamento farmacológico , Animais , Biomarcadores , Encéfalo/efeitos dos fármacos , Encéfalo/crescimento & desenvolvimento , Intervenção Médica Precoce/métodos , Humanos , Terapia de Alvo Molecular/métodos , Apoio à Pesquisa como Assunto
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