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1.
Dev Cogn Neurosci ; 58: 101178, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36434964

RESUMO

Motion remains a significant technical hurdle in fMRI studies of young children. Our aim was to develop a straightforward and effective method for obtaining and preprocessing resting state data from a high-motion pediatric cohort. This approach combines real-time monitoring of head motion with a preprocessing pipeline that uses volume censoring and concatenation alongside independent component analysis based denoising. We evaluated this method using a sample of 108 first grade children (age 6-8) enrolled in a longitudinal study of math development. Data quality was assessed by analyzing the correlation between participant head motion and two key metrics for resting state data, temporal signal-to-noise and functional connectivity. These correlations should be minimal in the absence of noise-related artifacts. We compared these data quality indicators using several censoring thresholds to determine the necessary degree of censoring. Volume censoring was highly effective at removing motion-corrupted volumes and ICA denoising removed much of the remaining motion artifact. With the censoring threshold set to exclude volumes that exceeded a framewise displacement of 0.3 mm, preprocessed data met rigorous standards for data quality while retaining a large majority of subjects (83 % of participants). Overall, results show it is possible to obtain usable resting-state data despite extreme motion in a group of young, untrained subjects.


Assuntos
Mapeamento Encefálico , Processamento de Imagem Assistida por Computador , Humanos , Criança , Pré-Escolar , Mapeamento Encefálico/métodos , Processamento de Imagem Assistida por Computador/métodos , Estudos Longitudinais , Movimento (Física) , Artefatos , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem
2.
Dev Sci ; 25(3): e13194, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34800342

RESUMO

Children's ability to discriminate nonsymbolic number (e.g., the number of items in a set) is a commonly studied predictor of later math skills. Number discrimination improves throughout development, but what drives this improvement is unclear. Competing theories suggest that it may be due to a sharpening numerical representation or an improved ability to pay attention to number and filter out non-numerical information. We investigate this issue by studying change in children's performance (N = 65) on a nonsymbolic number comparison task, where children decide which of two dot arrays has more dots, from the middle to the end of 1st grade (mean age at time 1 = 6.85 years old). In this task, visual properties of the dot arrays such as surface area are either congruent (the more numerous array has more surface area) or incongruent. Children rely more on executive functions during incongruent trials, so improvements in each congruency condition provide information about the underlying cognitive mechanisms. We found that accuracy rates increased similarly for both conditions, indicating a sharpening sense of numerical magnitude, not simply improved attention to the numerical task dimension. Symbolic number skills predicted change in congruent trials, but executive function did not predict change in either condition. No factor predicted change in math achievement. Together, these findings suggest that nonsymbolic number processing undergoes development related to existing symbolic number skills, development that appears not to be driving math gains during this period. Children's ability to discriminate nonsymbolic number improves throughout development. Competing theories suggest improvement due to sharpening magnitude representations or changes in attention and inhibition. The current study investigates change in nonsymbolic number comparison performance during first grade and whether symbolic number skills, math skills, or executive function predict change. Children's performance increased across visual control conditions (i.e., congruent or incongruent with number) suggesting an overall sharpening of number processing. Symbolic number skills predicted change in nonsymbolic number comparison performance.


Assuntos
Logro , Função Executiva , Criança , Humanos , Inibição Psicológica , Matemática
3.
Neuropsychopharmacology ; 46(10): 1788-1801, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34035472

RESUMO

Broad-based cognitive deficits are an enduring and disabling symptom for many patients with severe mental illness, and these impairments are inadequately addressed by current medications. While novel drug targets for schizophrenia and depression have emerged from recent large-scale genome-wide association studies (GWAS) of these psychiatric disorders, GWAS of general cognitive ability can suggest potential targets for nootropic drug repurposing. Here, we (1) meta-analyze results from two recent cognitive GWAS to further enhance power for locus discovery; (2) employ several complementary transcriptomic methods to identify genes in these loci that are credibly associated with cognition; and (3) further annotate the resulting genes using multiple chemoinformatic databases to identify "druggable" targets. Using our meta-analytic data set (N = 373,617), we identified 241 independent cognition-associated loci (29 novel), and 76 genes were identified by 2 or more methods of gene identification. Actin and chromatin binding gene sets were identified as novel pathways that could be targeted via drug repurposing. Leveraging our transcriptomic and chemoinformatic databases, we identified 16 putative genes targeted by existing drugs potentially available for cognitive repurposing.


Assuntos
Nootrópicos , Esquizofrenia , Cognição , Estudo de Associação Genômica Ampla , Humanos , Esquizofrenia/tratamento farmacológico , Esquizofrenia/genética , Transcriptoma
4.
Schizophr Res ; 227: 10-17, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32402605

RESUMO

BACKGROUND: Malhi et al. in this issue critique the clinical high risk (CHR) syndrome for psychosis. METHOD: Response to points of critique. RESULTS: We agree that inconsistency in CHR nomenclature should be minimized. We respectfully disagree on other points. In our view: a) individuals with CHR and their families need help, using existing interventions, even though we do not yet fully understand disease mechanisms; b) substantial progress has been made in identification of biomarkers; c) symptoms used to identify CHR are specific to psychotic illnesses; d) CHR diagnosis is not "extremely difficult"; e) the pattern of progression, although heterogenous, is discernible; f) "psychosis-like symptoms" are common but are not used to identify CHR; and g) on the point described as 'the real risk,' CHR diagnosis does not frequently cause harmful stigma. DISCUSSION: Malhi et al.'s arguments do not fairly characterize progress in the CHR field nor efforts to minimize stigma. That said, much work remains in areas of consistent nomenclature, mechanisms of disease, dissecting heterogeneity, and biomarkers. With regard to what the authors term the "real risk" of stigma associated with a CHR "label," however, our view is that avoiding words like "risk" and "psychosis" reinforces the stigma that both they and we mean to oppose. Moreover, patients and their families benefit from being given a term that describes what is happening to them.


Assuntos
Transtornos Psicóticos , Humanos , Transtornos Psicóticos/diagnóstico , Transtornos Psicóticos/terapia , Estigma Social , Síndrome
5.
Am J Hum Genet ; 105(2): 334-350, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31374203

RESUMO

Susceptibility to schizophrenia is inversely correlated with general cognitive ability at both the phenotypic and the genetic level. Paradoxically, a modest but consistent positive genetic correlation has been reported between schizophrenia and educational attainment, despite the strong positive genetic correlation between cognitive ability and educational attainment. Here we leverage published genome-wide association studies (GWASs) in cognitive ability, education, and schizophrenia to parse biological mechanisms underlying these results. Association analysis based on subsets (ASSET), a pleiotropic meta-analytic technique, allowed jointly associated loci to be identified and characterized. Specifically, we identified subsets of variants associated in the expected ("concordant") direction across all three phenotypes (i.e., greater risk for schizophrenia, lower cognitive ability, and lower educational attainment); these were contrasted with variants that demonstrated the counterintuitive ("discordant") relationship between education and schizophrenia (i.e., greater risk for schizophrenia and higher educational attainment). ASSET analysis revealed 235 independent loci associated with cognitive ability, education, and/or schizophrenia at p < 5 × 10-8. Pleiotropic analysis successfully identified more than 100 loci that were not significant in the input GWASs. Many of these have been validated by larger, more recent single-phenotype GWASs. Leveraging the joint genetic correlations of cognitive ability, education, and schizophrenia, we were able to dissociate two distinct biological mechanisms-early neurodevelopmental pathways that characterize concordant allelic variation and adulthood synaptic pruning pathways-that were linked to the paradoxical positive genetic association between education and schizophrenia. Furthermore, genetic correlation analyses revealed that these mechanisms contribute not only to the etiopathogenesis of schizophrenia but also to the broader biological dimensions implicated in both general health outcomes and psychiatric illness.


Assuntos
Transtornos Cognitivos/fisiopatologia , Cognição/fisiologia , Escolaridade , Transtornos do Neurodesenvolvimento/etiologia , Polimorfismo de Nucleotídeo Único , Esquizofrenia/fisiopatologia , Transmissão Sináptica , Adulto , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Transtornos do Neurodesenvolvimento/patologia
6.
Brain Behav ; 8(6): e00988, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-30106252

RESUMO

INTRODUCTION: Working Memory and Task-Switching are essential components of cognitive control, which underlies many symptoms evident across multiple neuropsychiatric disorders, including psychotic and mood disorders. Vulnerability to these disorders has a substantial genetic component, suggesting that clinically unaffected first-degree relatives may carry some vulnerability-related traits. Converging evidence from animal and human studies demonstrates that dopamine transmission, striatal and frontal brain regions, and attention and switching behaviors are essential components of a multilevel circuit involved in salience, and disruptions in that circuit may lead to features of psychosis. Yet, it is possible that unaffected relatives may also possess characteristics that protect against development of illness. We hypothesized that reduced switch cost in a cued task-switching task, may be a behavioral expression of this "resilience" phenotype that will be observable in unaffected relatives. METHODS: We tested a large community sample (n = 536) via the web, to assess different subcomponents of cognitive control, including task-switching and working memory, as well as risk-taking, among individuals who report having an affected relative with a psychotic or mood disorder. RESULTS: Healthy individuals with suspected genetic risk due to a self-reported familial history of a psychotic disorder demonstrated better task-switching performance compared to healthy people without a psychiatrically ill relative and those with a relative with a mood disorder. This result was specific to illness status and task domain, in that individuals with a personal history of depression or anxiety did not show improved task-switching performance, and this improvement was selective to task-switching and not seen in other putative cognitive control domains (working memory or risk taking). CONCLUSIONS: Although this study has limitations and independent replication is needed, these preliminary findings suggest a potential avenue for understanding susceptibility to these disorders by highlighting possible protective as well as vulnerability-related aspects of risk phenotypes.


Assuntos
Atenção/fisiologia , Memória de Curto Prazo/fisiologia , Transtornos Psicóticos/psicologia , Adulto , Feminino , Lobo Frontal/fisiologia , Humanos , Masculino , Testes Neuropsicológicos , Fenótipo , Transtornos Psicóticos/genética , Tempo de Reação/fisiologia , Resiliência Psicológica , Fatores de Risco , Autorrelato , Memória Espacial/fisiologia , Adulto Jovem
7.
Twin Res Hum Genet ; 21(5): 394-397, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30001766

RESUMO

Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84-88) presented a critique of our recently published paper in Cell Reports entitled 'Large-Scale Cognitive GWAS Meta-Analysis Reveals Tissue-Specific Neural Expression and Potential Nootropic Drug Targets' (Lam et al., Cell Reports, Vol. 21, 2017, 2597-2613). Specifically, Hill offered several interrelated comments suggesting potential problems with our use of a new analytic method called Multi-Trait Analysis of GWAS (MTAG) (Turley et al., Nature Genetics, Vol. 50, 2018, 229-237). In this brief article, we respond to each of these concerns. Using empirical data, we conclude that our MTAG results do not suffer from 'inflation in the FDR [false discovery rate]', as suggested by Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84-88), and are not 'more relevant to the genetic contributions to education than they are to the genetic contributions to intelligence'.


Assuntos
Estudo de Associação Genômica Ampla , Nootrópicos , Cognição , Predisposição Genética para Doença , Humanos , Polimorfismo de Nucleotídeo Único
8.
Schizophr Bull ; 44(5): 1045-1052, 2018 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-29534239

RESUMO

Genetic risk variants for schizophrenia have been linked to many related clinical and biological phenotypes with the hopes of delineating how individual variation across thousands of variants corresponds to the clinical and etiologic heterogeneity within schizophrenia. This has primarily been done using risk score profiling, which aggregates effects across all variants into a single predictor. While effective, this method lacks flexibility in certain domains: risk scores cannot capture nonlinear effects and do not employ any variable selection. We used random forest, an algorithm with this flexibility designed to maximize predictive power, to predict 6 cognitive endophenotypes in a combined sample of psychiatric patients and controls (N = 739) using 77 genetic variants strongly associated with schizophrenia. Tenfold cross-validation was applied to the discovery sample and models were externally validated in an independent sample of similar ancestry (N = 336). Linear approaches, including linear regression and task-specific polygenic risk scores, were employed for comparison. Random forest models for processing speed (P = .019) and visual memory (P = .036) and risk scores developed for verbal (P = .042) and working memory (P = .037) successfully generalized to an independent sample with similar predictive strength and error. As such, we suggest that both methods may be useful for mapping a limited set of predetermined, disease-associated SNPs to related phenotypes. Incorporating random forest and other more flexible algorithms into genotype-phenotype mapping inquiries could contribute to parsing heterogeneity within schizophrenia; such algorithms can perform as well as standard methods and can capture a more comprehensive set of potential relationships.


Assuntos
Disfunção Cognitiva , Genótipo , Aprendizado de Máquina , Herança Multifatorial/fisiologia , Fenótipo , Sistema de Registros , Esquizofrenia , Adulto , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/genética , Disfunção Cognitiva/fisiopatologia , Endofenótipos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Herança Multifatorial/genética , Polimorfismo de Nucleotídeo Único , Esquizofrenia/complicações , Esquizofrenia/genética , Esquizofrenia/fisiopatologia , Suécia , Estados Unidos , Adulto Jovem
9.
Cell Rep ; 21(9): 2597-2613, 2017 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-29186694

RESUMO

Here, we present a large (n = 107,207) genome-wide association study (GWAS) of general cognitive ability ("g"), further enhanced by combining results with a large-scale GWAS of educational attainment. We identified 70 independent genomic loci associated with general cognitive ability. Results showed significant enrichment for genes causing Mendelian disorders with an intellectual disability phenotype. Competitive pathway analysis implicated the biological processes of neurogenesis and synaptic regulation, as well as the gene targets of two pharmacologic agents: cinnarizine, a T-type calcium channel blocker, and LY97241, a potassium channel inhibitor. Transcriptome-wide and epigenome-wide analysis revealed that the implicated loci were enriched for genes expressed across all brain regions (most strongly in the cerebellum). Enrichment was exclusive to genes expressed in neurons but not oligodendrocytes or astrocytes. Finally, we report genetic correlations between cognitive ability and disparate phenotypes including psychiatric disorders, several autoimmune disorders, longevity, and maternal age at first birth.


Assuntos
Estudo de Associação Genômica Ampla/métodos , Nootrópicos/farmacologia , Cefotaxima/análogos & derivados , Cefotaxima/farmacologia , Cognição/efeitos dos fármacos , Cognição/fisiologia , Feminino , Loci Gênicos/genética , Predisposição Genética para Doença/genética , Humanos , Masculino , Polimorfismo de Nucleotídeo Único/genética , Sinapses/efeitos dos fármacos , Sinapses/metabolismo
10.
Am J Drug Alcohol Abuse ; 43(3): 271-280, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-27439543

RESUMO

BACKGROUND: Smokers exhibit an unusually high willingness to forgo a delayed reward of greater magnitude to receive a smaller, more immediate reward. The functional form of such "delay discounting" behavior is central to the discounting-based operationalization of impulsivity, and has implications for theories regarding the basis of steep discounting among smokers and treatment approaches to addiction. OBJECTIVES: We examined the discounting behavior of current smokers, ex-smokers, and never-smokers to determine whether the functional form of discounting differs between these groups. METHODS: Participants completed a 27-item delay discounting questionnaire (25). We used finite mixture modeling in analyzing data as the product of two simultaneous data-generating processes (DGPs), a hyperbolic function and an exponential function, and compared results to a quasi-hyperbolic (QH) approximation, in a relatively large sample (n = 1205). RESULTS: Consistent with prior reports, current smokers exhibited steeper discounting relative to never-smokers across exponential, hyperbolic, and QH models. A mixture model provided significant support for exponential and hyperbolic discounting in the data, and both accounted for roughly 50% of the participants' choices. This mixture model showed a statistically significantly better fit to the data than the exponential, hyperbolic, or QH functions alone. Contrary to the prevailing view, current smokers were not more likely to discount hyperbolically than nonsmokers, and, thus, were not more prone to time-inconsistent discounting. CONCLUSIONS: The results inform the interpretation of steep discounting among smokers and suggest that treatment approaches could be tailored to the type of discounting behavior that smokers exhibit.


Assuntos
Desvalorização pelo Atraso , Comportamento Impulsivo , Modelos Estatísticos , Fumar/psicologia , Adulto , Comportamento de Escolha , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recompensa , Fumantes/psicologia , Inquéritos e Questionários , Adulto Jovem
11.
Schizophr Res ; 168(1-2): 223-30, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26299707

RESUMO

OBJECTIVE: Schizophrenia patients exhibit impaired working and episodic memory, but this may represent generalized impairment across memory modalities or performance deficits restricted to particular memory systems in subgroups of patients. Furthermore, it is unclear whether deficits are unique from those associated with other disorders. METHOD: Healthy controls (n=1101) and patients with schizophrenia (n=58), bipolar disorder (n=49) and attention-deficit-hyperactivity-disorder (n=46) performed 18 tasks addressing primarily verbal and spatial episodic and working memory. Effect sizes for group contrasts were compared across tasks and the consistency of subjects' distributional positions across memory domains was measured. RESULTS: Schizophrenia patients performed poorly relative to the other groups on every test. While low to moderate correlation was found between memory domains (r=.320), supporting modularity of these systems, there was limited agreement between measures regarding each individual's task performance (ICC=.292) and in identifying those individuals falling into the lowest quintile (kappa=0.259). A general ability factor accounted for nearly all of the group differences in performance and agreement across measures in classifying low performers. CONCLUSIONS: Pathophysiological processes involved in schizophrenia appear to act primarily on general abilities required in all tasks rather than on specific abilities within different memory domains and modalities. These effects represent a general shift in the overall distribution of general ability (i.e., each case functioning at a lower level than they would have if not for the illness), rather than presence of a generally low-performing subgroup of patients. There is little evidence that memory impairments in schizophrenia are shared with bipolar disorder and ADHD.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/psicologia , Transtorno Bipolar/psicologia , Transtornos da Memória/complicações , Psicologia do Esquizofrênico , Adulto , Cognição , Feminino , Humanos , Masculino , Memória Episódica , Memória de Curto Prazo , Pessoa de Meia-Idade , Testes Neuropsicológicos , Análise de Componente Principal , Escalas de Graduação Psiquiátrica , Esquizofrenia/complicações , Adulto Jovem
12.
J Neurosci ; 35(15): 5990-7, 2015 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-25878272

RESUMO

Motor response inhibition is mediated by neural circuits involving dopaminergic transmission; however, the relative contributions of dopaminergic signaling via D1- and D2-type receptors are unclear. Although evidence supports dissociable contributions of D1- and D2-type receptors to response inhibition in rats and associations of D2-type receptors to response inhibition in humans, the relationship between D1-type receptors and response inhibition has not been evaluated in humans. Here, we tested whether individual differences in striatal D1- and D2-type receptors are related to response inhibition in human subjects, possibly in opposing ways. Thirty-one volunteers participated. Response inhibition was indexed by stop-signal reaction time on the stop-signal task and commission errors on the continuous performance task, and tested for association with striatal D1- and D2-type receptor availability [binding potential referred to nondisplaceable uptake (BPND)], measured using positron emission tomography with [(11)C]NNC-112 and [(18)F]fallypride, respectively. Stop-signal reaction time was negatively correlated with D1- and D2-type BPND in whole striatum, with significant relationships involving the dorsal striatum, but not the ventral striatum, and no significant correlations involving the continuous performance task. The results indicate that dopamine D1- and D2-type receptors are associated with response inhibition, and identify the dorsal striatum as an important locus of dopaminergic control in stopping. Moreover, the similar contribution of both receptor subtypes suggests the importance of a relative balance between phasic and tonic dopaminergic activity subserved by D1- and D2-type receptors, respectively, in support of response inhibition. The results also suggest that the stop-signal task and the continuous performance task use different neurochemical mechanisms subserving motor response inhibition.


Assuntos
Corpo Estriado/fisiologia , Inibição Psicológica , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , Adulto , Benzamidas/farmacocinética , Benzazepinas/farmacocinética , Benzofuranos/farmacocinética , Comportamento de Escolha , Corpo Estriado/diagnóstico por imagem , Corpo Estriado/efeitos dos fármacos , Feminino , Fluordesoxiglucose F18/farmacocinética , Humanos , Imageamento Tridimensional , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Tomografia por Emissão de Pósitrons , Análise de Regressão , Adulto Jovem
13.
Br J Psychol ; 105(2): 254-72, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24754812

RESUMO

Sexual dimorphism in the brain and cognition is a topic of widespread interest. Many studies of sex differences have focused on visuospatial and verbal abilities, but few studies have investigated sex differences in executive functions. We examined two key components of executive function - response inhibition and response monitoring - in healthy men (n = 285) and women (n = 346) performing the Stop-signal task. In this task, participants are required to make a key press to a stimulus, unless a tone is presented at some delay following the initial stimulus presentation; on these infrequent trials, participants are instructed to inhibit their planned response. Response inhibition was assessed with an estimate of the latency needed to inhibit a response (stop-signal reaction time), and response monitoring was measured by calculating the degree to which participants adjusted their reaction times based on the immediately preceding trial (e.g., speeding following correct trials and slowing following errors). There were no sex differences in overall accuracy or response inhibition, but women showed greater sensitivity to trial history. Women sped up more than men following correct 'Go' trials, and slowed down more than men following errors. These small but statistically significant effects (Cohen's d = 0.25-0.3) suggest more flexible adjustments in speed-accuracy trade-offs in women and greater cognitive flexibility associated with the responsive control of action.


Assuntos
Atenção , Função Executiva/fisiologia , Inibição Psicológica , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Estimulação Acústica , Adulto , Cognição/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa , Fatores Sexuais , Adulto Jovem
14.
Psychiatry Res ; 222(1-2): 17-28, 2014 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-24581734

RESUMO

Studies of adults with attention-deficit/hyperactivity disorder (ADHD) have suggested that they have deficient response inhibition, but findings concerning the neural correlates of inhibition in this patient population are inconsistent. We used the Stop-Signal task and functional magnetic resonance imaging (fMRI) to compare neural activation associated with response inhibition between adults with ADHD (N=35) and healthy comparison subjects (N=62), and in follow-up tests to examine the effect of current medication use and symptom severity. There were no differences in Stop-Signal task performance or neural activation between ADHD and control participants. Among the ADHD participants, however, significant differences were associated with current medication, with individuals taking psychostimulants (N=25) showing less stopping-related activation than those not currently receiving psychostimulant medication (N=10). Follow-up analyses suggested that this difference in activation was independent of symptom severity. These results provide evidence that deficits in inhibition-related neural activation persist in a subset of adult ADHD individuals, namely those individuals currently taking psychostimulants. These findings help to explain some of the disparities in the literature, and advance our understanding of why deficits in response inhibition are more variable in adult, as compared with child and adolescent, ADHD patients.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Atenção/fisiologia , Encéfalo/fisiopatologia , Estimulantes do Sistema Nervoso Central/uso terapêutico , Inibição Psicológica , Imageamento por Ressonância Magnética/métodos , Adulto , Atenção/efeitos dos fármacos , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Transtorno do Deficit de Atenção com Hiperatividade/tratamento farmacológico , Encéfalo/efeitos dos fármacos , Mapeamento Encefálico , Estimulantes do Sistema Nervoso Central/farmacologia , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Índice de Gravidade de Doença , Análise e Desempenho de Tarefas , Adulto Jovem
15.
Proc Natl Acad Sci U S A ; 111(7): 2470-5, 2014 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-24550270

RESUMO

Previous research has implicated a large network of brain regions in the processing of risk during decision making. However, it has not yet been determined if activity in these regions is predictive of choices on future risky decisions. Here, we examined functional MRI data from a large sample of healthy subjects performing a naturalistic risk-taking task and used a classification analysis approach to predict whether individuals would choose risky or safe options on upcoming trials. We were able to predict choice category successfully in 71.8% of cases. Searchlight analysis revealed a network of brain regions where activity patterns were reliably predictive of subsequent risk-taking behavior, including a number of regions known to play a role in control processes. Searchlights with significant predictive accuracy were primarily located in regions more active when preparing to avoid a risk than when preparing to engage in one, suggesting that risk taking may be due, in part, to a failure of the control systems necessary to initiate a safe choice. Additional analyses revealed that subject choice can be successfully predicted with minimal decrements in accuracy using highly condensed data, suggesting that information relevant for risky choice behavior is encoded in coarse global patterns of activation as well as within highly local activation within searchlights.


Assuntos
Comportamento de Escolha/fisiologia , Rede Nervosa/fisiologia , Assunção de Riscos , Cognição/fisiologia , Humanos , Imageamento por Ressonância Magnética , Testes Neuropsicológicos
16.
J Cogn Neurosci ; 26(8): 1601-14, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24405185

RESUMO

The stop-signal task, in which participants must inhibit prepotent responses, has been used to identify neural systems that vary with individual differences in inhibitory control. To explore how these differences relate to other aspects of decision making, a drift-diffusion model of simple decisions was fitted to stop-signal task data from go trials to extract measures of caution, motor execution time, and stimulus processing speed for each of 123 participants. These values were used to probe fMRI data to explore individual differences in neural activation. Faster processing of the go stimulus correlated with greater activation in the right frontal pole for both go and stop trials. On stop trials, stimulus processing speed also correlated with regions implicated in inhibitory control, including the right inferior frontal gyrus, medial frontal gyrus, and BG. Individual differences in motor execution time correlated with activation of the right parietal cortex. These findings suggest a robust relationship between the speed of stimulus processing and inhibitory processing at the neural level. This model-based approach provides novel insight into the interrelationships among decision components involved in inhibitory control and raises interesting questions about strategic adjustments in performance and inhibitory deficits associated with psychopathology.


Assuntos
Tomada de Decisões/fisiologia , Função Executiva/fisiologia , Neuroimagem Funcional/métodos , Individualidade , Inibição Psicológica , Desempenho Psicomotor/fisiologia , Adulto , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Modelos Psicológicos , Córtex Pré-Frontal/fisiologia , Adulto Jovem
17.
Front Neurosci ; 7: 173, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24137106

RESUMO

Despite evidence supporting a relationship between impulsivity and naturalistic risk-taking, the relationship of impulsivity with laboratory-based measures of risky decision-making remains unclear. One factor contributing to this gap in our understanding is the degree to which different risky decision-making tasks vary in their details. We conducted an fMRI investigation of the Angling Risk Task (ART), which is an improved behavioral measure of risky decision-making. In order to examine whether the observed pattern of neural activation was specific to the ART or generalizable, we also examined correlates of the Balloon Analog Risk Taking (BART) task in the same sample of 23 healthy adults. Exploratory analyses were conducted to examine the relationship between neural activation, performance, impulsivity and self-reported risk-taking. While activation in a valuation network was associated with reward tracking during the ART but not the BART, increased fronto-cingulate activation was seen during risky choice trials in the BART as compared to the ART. Thus, neural activation during risky decision-making trials differed between the two tasks, and this observation was likely driven by differences in task parameters, namely the absence vs. presence of ambiguity and/or stationary vs. increasing probability of loss on the ART and BART, respectively. Exploratory association analyses suggest that sensitivity of neural response to the magnitude of potential reward during the ART was associated with a suboptimal performance strategy, higher scores on a scale of dysfunctional impulsivity (DI) and a greater likelihood of engaging in risky behaviors, while this pattern was not seen for the BART. Our results suggest that the ART is decomposable and associated with distinct patterns of neural activation; this represents a preliminary step toward characterizing a behavioral measure of risky decision-making that may support a better understanding of naturalistic risk-taking.

18.
J Abnorm Psychol ; 122(3): 917-27, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23647123

RESUMO

Systematic efforts are underway to address major flaws in the current diagnostic taxonomy of mental disorders, fostering hope that a new nosology might be based on brain biology. The National Institute of Mental Health Research Domains Criteria (RDoC) initiative aims to redefine mental illness leveraging information that spans molecular to behavioral levels of analysis. Major effort is still needed to forge multilevel conceptual and measurement models capable of representing knowledge within and across these levels. The development of such models may help refine and share complex hypotheses, and reduce the risk of replacing the current taxonomy with dimensions and/or categories that manifest little incremental biological validity. To create useful models we need to define concepts, relations among concepts, and links to supporting evidence. Some methods already enable representation of concepts and measures at the levels of behavioral and basic biological processes, but a major gap at the level of neural circuitry must be bridged to link basic biological and behavioral levels. We provide a schematic framework, using as an example the representation of selected "working memory" concepts and evidence across multiple levels of analysis as these have been described in the RDoC Workshops. This example illustrates multiple challenges and some possible solutions that may help clarify the aims of individual research projects and enable integration of diverse efforts on RDoC and related initiatives.


Assuntos
Transtornos Mentais/classificação , Modelos Neurológicos , Modelos Psicológicos , Humanos , Memória/fisiologia , Transtornos Mentais/fisiopatologia
19.
Psychol Assess ; 25(2): 631-42, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23544402

RESUMO

The Barratt Impulsiveness Scale (Version 11; BIS-11; Patton, Stanford, & Barratt, 1995) is a gold-standard measure that has been influential in shaping current theories of impulse control, and has played a key role in studies of impulsivity and its biological, psychological, and behavioral correlates. Psychometric research on the structure of the BIS-11, however, has been scant. We therefore applied exploratory and confirmatory factor analyses to data collected using the BIS-11 in a community sample (N = 691). Our goal was to test 4 theories of the BIS-11 structure: (a) a unidimensional model, (b) a 6 correlated first-order factor model, (c) a 3 second-order factor model, and (d) a bifactor model. Among the problems identified were (a) low or near-zero correlations of some items with others; (b) highly redundant content of numerous item pairs; (c) items with salient cross-loadings in multidimensional solutions; and, ultimately, (d) poor fit to confirmatory models. We conclude that use of the BIS-11 total score as reflecting individual differences on a common dimension of impulsivity presents challenges in interpretation. Also, the theory that the BIS-11 measures 3 subdomains of impulsivity (attention, motor, and nonplanning) was not empirically supported. A 2-factor model is offered as an alternative multidimensional structural representation.


Assuntos
Comportamento Impulsivo/diagnóstico , Escalas de Graduação Psiquiátrica/normas , Psicometria/normas , Adulto , Análise Fatorial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Teoria Psicológica , Sensibilidade e Especificidade , Adulto Jovem
20.
Brain Behav ; 3(5): 552-61, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24392276

RESUMO

Introduction Understanding the relationship between brain and complex latent behavioral constructs like cognitive control will require an inordinate amount of data. Internet-based methods can rapidly and efficiently refine behavioral measures in very large samples that are needed for genetics and behavioral research. Cognitive control is a multifactorial latent construct that is considered to be an endophenotype in numerous neuropsychiatric disorders, including attention deficit/hyperactivity disorder (ADHD). While previous studies have demonstrated high correlations between Web- and lab-based scores, skepticism remains for its broad implementation. Methods Here, we promote a different approach by characterizing a completely Web-recruited and tested community family sample on measures of cognitive control. We examine the prevalence of attention deficit symptoms in an online community sample of adolescents, demonstrate familial correlations in cognitive control measures, and use construct validation techniques to validate our high-throughput assessment approach. Results A total of 1214 participants performed Web-based tests of cognitive control with over 200 parent-child pairs analyzed as part of the primary study aims. The data show a wide range of "subclinical" symptomatology in a web community sample of adolescents that supports a dimensional view of attention and also provide preliminary narrow-sense heritability estimates for commonly used working memory and response inhibition tests. Conclusions Finally, we show strong face and construct validity for these measures of cognitive control that generally exceeds the evidence required of new lab-based measures. We discuss these results and how broad implementation of this platform may allow us to uncover important brain-behavior relationships quickly and efficiently.

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