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1.
Cogn Affect Behav Neurosci ; 24(4): 720-739, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38773022

RESUMO

"Pavlovian" or "motivational" biases describe the phenomenon that the valence of prospective outcomes modulates action invigoration: Reward prospect invigorates action, whereas punishment prospect suppresses it. The adaptive role of these biases in decision-making is still unclear. One idea is that they constitute a fast-and-frugal decision strategy in situations characterized by high arousal, e.g., in presence of a predator, which demand a quick response. In this pre-registered study (N = 35), we tested whether such a situation-induced via subliminally presented angry versus neutral faces-leads to increased reliance on Pavlovian biases. We measured trial-by-trial arousal by tracking pupil diameter while participants performed an orthogonalized Motivational Go/NoGo Task. Pavlovian biases were present in responses, reaction times, and even gaze, with lower gaze dispersion under aversive cues reflecting "freezing of gaze." The subliminally presented faces did not affect responses, reaction times, or pupil diameter, suggesting that the arousal manipulation was ineffective. However, pupil dilations reflected facets of bias suppression, specifically the physical (but not cognitive) effort needed to overcome aversive inhibition: Particularly strong and sustained dilations occurred when participants managed to perform Go responses to aversive cues. Conversely, no such dilations occurred when they managed to inhibit responses to Win cues. These results suggest that pupil diameter does not reflect response conflict per se nor the inhibition of prepotent responses, but specifically effortful action invigoration as needed to overcome aversive inhibition. We discuss our results in the context of the "value of work" theory of striatal dopamine.


Assuntos
Condicionamento Clássico , Motivação , Pupila , Tempo de Reação , Humanos , Pupila/fisiologia , Masculino , Feminino , Adulto Jovem , Adulto , Condicionamento Clássico/fisiologia , Tempo de Reação/fisiologia , Motivação/fisiologia , Nível de Alerta/fisiologia , Inibição Psicológica , Expressão Facial , Tomada de Decisões/fisiologia , Recompensa , Sinais (Psicologia)
2.
PLoS Biol ; 18(10): e3000908, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33108370

RESUMO

Flexible behavior is critical for everyday decision-making and has been implicated in restricted, repetitive behaviors (RRB) in autism spectrum disorder (ASD). However, how flexible behavior changes developmentally in ASD remains largely unknown. Here, we used a developmental approach and examined flexible behavior on a probabilistic reversal learning task in 572 children, adolescents, and adults (ASD N = 321; typical development [TD] N = 251). Using computational modeling, we quantified latent variables that index mechanisms underlying perseveration and feedback sensitivity. We then assessed these variables in relation to diagnosis, developmental stage, core autism symptomatology, and associated psychiatric symptoms. Autistic individuals showed on average more perseveration and less feedback sensitivity than TD individuals, and, across cases and controls, older age groups showed more feedback sensitivity than younger age groups. Computational modeling revealed that dominant learning mechanisms underpinning flexible behavior differed across developmental stages and reduced flexible behavior in ASD was driven by less optimal learning on average within each age group. In autistic children, perseverative errors were positively related to anxiety symptoms, and in autistic adults, perseveration (indexed by both task errors and model parameter estimates) was positively related to RRB. These findings provide novel insights into reduced flexible behavior in relation to clinical symptoms in ASD.


Assuntos
Envelhecimento/fisiologia , Transtorno Autístico/fisiopatologia , Comportamento , Aprendizagem/fisiologia , Modelos Biológicos , Adolescente , Adulto , Fatores Etários , Criança , Feminino , Humanos , Testes de Inteligência , Masculino , Reprodutibilidade dos Testes , Análise e Desempenho de Tarefas , Adulto Jovem
3.
Cereb Cortex ; 32(14): 2924-2942, 2022 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-34849626

RESUMO

Action selection is biased by the valence of anticipated outcomes. To assess mechanisms by which these motivational biases are expressed and controlled, we measured simultaneous EEG-fMRI during a motivational Go/NoGo learning task (N = 36), leveraging the temporal resolution of EEG and subcortical access of fMRI. VmPFC BOLD encoded cue valence, importantly predicting trial-by-trial valence-driven response speed differences and EEG theta power around cue onset. In contrast, striatal BOLD encoded selection of active Go responses and correlated with theta power around response time. Within trials, theta power ramped in the fashion of an evidence accumulation signal for the value of making a "Go" response, capturing the faster responding to reward cues. Our findings reveal a dual nature of midfrontal theta power, with early components reflecting the vmPFC contribution to motivational biases, and late components reflecting their striatal translation into behavior, in line with influential recent "value of work" theories of striatal processing.


Assuntos
Motivação , Ritmo Teta , Eletroencefalografia , Imageamento por Ressonância Magnética , Recompensa , Ritmo Teta/fisiologia
4.
Psychol Med ; 52(2): 303-313, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-32538342

RESUMO

BACKGROUND: Classic theories posit that depression is driven by a negative learning bias. Most studies supporting this proposition used small and selected samples, excluding patients with comorbidities. However, comorbidity between psychiatric disorders occurs in up to 70% of the population. Therefore, the generalizability of the negative bias hypothesis to a naturalistic psychiatric sample as well as the specificity of the bias to depression, remain unclear. In the present study, we tested the negative learning bias hypothesis in a large naturalistic sample of psychiatric patients, including depression, anxiety, addiction, attention-deficit/hyperactivity disorder, and/or autism. First, we assessed whether the negative bias hypothesis of depression generalized to a heterogeneous (and hence more naturalistic) depression sample compared with controls. Second, we assessed whether negative bias extends to other psychiatric disorders. Third, we adopted a dimensional approach, by using symptom severity as a way to assess associations across the sample. METHODS: We administered a probabilistic reversal learning task to 217 patients and 81 healthy controls. According to the negative bias hypothesis, participants with depression should exhibit enhanced learning and flexibility based on punishment v. reward. We combined analyses of traditional measures with more sensitive computational modeling. RESULTS: In contrast to previous findings, this sample of depressed patients with psychiatric comorbidities did not show a negative learning bias. CONCLUSIONS: These results speak against the generalizability of the negative learning bias hypothesis to depressed patients with comorbidities. This study highlights the importance of investigating unselected samples of psychiatric patients, which represent the vast majority of the psychiatric population.


Assuntos
Depressão , Reversão de Aprendizagem , Transtornos de Ansiedade/epidemiologia , Depressão/epidemiologia , Humanos , Punição , Recompensa
5.
Psychol Med ; : 1-12, 2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36411719

RESUMO

BACKGROUND: The non-selective serotonin 2A (5-HT2A) receptor agonist lysergic acid diethylamide (LSD) holds promise as a treatment for some psychiatric disorders. Psychedelic drugs such as LSD have been suggested to have therapeutic actions through their effects on learning. The behavioural effects of LSD in humans, however, remain incompletely understood. Here we examined how LSD affects probabilistic reversal learning (PRL) in healthy humans. METHODS: Healthy volunteers received intravenous LSD (75 µg in 10 mL saline) or placebo (10 mL saline) in a within-subjects design and completed a PRL task. Participants had to learn through trial and error which of three stimuli was rewarded most of the time, and these contingencies switched in a reversal phase. Computational models of reinforcement learning (RL) were fitted to the behavioural data to assess how LSD affected the updating ('learning rates') and deployment of value representations ('reinforcement sensitivity') during choice, as well as 'stimulus stickiness' (choice repetition irrespective of reinforcement history). RESULTS: Raw data measures assessing sensitivity to immediate feedback ('win-stay' and 'lose-shift' probabilities) were unaffected, whereas LSD increased the impact of the strength of initial learning on perseveration. Computational modelling revealed that the most pronounced effect of LSD was the enhancement of the reward learning rate. The punishment learning rate was also elevated. Stimulus stickiness was decreased by LSD, reflecting heightened exploration. Reinforcement sensitivity differed by phase. CONCLUSIONS: Increased RL rates suggest LSD induced a state of heightened plasticity. These results indicate a potential mechanism through which revision of maladaptive associations could occur in the clinical application of LSD.

6.
PLoS Biol ; 16(10): e2005979, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30335745

RESUMO

Motivation exerts control over behavior by eliciting Pavlovian responses, which can either match or conflict with instrumental action. We can overcome maladaptive motivational influences putatively through frontal cognitive control. However, the neurocomputational mechanisms subserving this control are unclear; does control entail up-regulating instrumental systems, down-regulating Pavlovian systems, or both? We combined electroencephalography (EEG) recordings with a motivational Go/NoGo learning task (N = 34), in which multiple Go options enabled us to disentangle selective action learning from nonselective Pavlovian responses. Midfrontal theta-band (4 Hz-8 Hz) activity covaried with the level of Pavlovian conflict and was associated with reduced Pavlovian biases rather than reduced instrumental learning biases. Motor and lateral prefrontal regions synchronized to the midfrontal cortex, and these network dynamics predicted the reduction of Pavlovian biases over and above local, midfrontal theta activity. This work links midfrontal processing to detecting Pavlovian conflict and highlights the importance of network processing in reducing the impact of maladaptive, Pavlovian biases.


Assuntos
Condicionamento Operante/fisiologia , Lobo Frontal/fisiologia , Motivação/fisiologia , Adolescente , Adulto , Viés , Comportamento de Escolha/fisiologia , Simulação por Computador , Tomada de Decisões/fisiologia , Eletroencefalografia/métodos , Feminino , Humanos , Aprendizagem/fisiologia , Masculino , Ritmo Teta
7.
Brain ; 143(11): 3422-3434, 2020 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-33147621

RESUMO

Parkinson's disease is clinically defined by bradykinesia, along with rigidity and tremor. However, the severity of these motor signs is greatly variable between individuals, particularly the presence or absence of tremor. This variability in tremor relates to variation in cognitive/motivational impairment, as well as the spatial distribution of neurodegeneration in the midbrain and dopamine depletion in the striatum. Here we ask whether interindividual heterogeneity in tremor symptoms could account for the puzzlingly large variability in the effects of dopaminergic medication on reinforcement learning, a fundamental cognitive function known to rely on dopamine. Given that tremor-dominant and non-tremor Parkinson's disease patients have different dopaminergic phenotypes, we hypothesized that effects of dopaminergic medication on reinforcement learning differ between tremor-dominant and non-tremor patients. Forty-three tremor-dominant and 20 non-tremor patients with Parkinson's disease were recruited to be tested both OFF and ON dopaminergic medication (200/50 mg levodopa-benserazide), while 22 age-matched control subjects were recruited to be tested twice OFF medication. Participants performed a reinforcement learning task designed to dissociate effects on learning rate from effects on motivational choice (i.e. the tendency to 'Go/NoGo' in the face of reward/threat of punishment). In non-tremor patients, dopaminergic medication improved reward-based choice, replicating previous studies. In contrast, in tremor-dominant patients, dopaminergic medication improved learning from punishment. Formal modelling showed divergent computational effects of dopaminergic medication as a function of Parkinson's disease motor phenotype, with a modulation of motivational choice bias and learning rate in non-tremor and tremor patients, respectively. This finding establishes a novel cognitive/motivational difference between tremor and non-tremor Parkinson's disease patients, and highlights the importance of considering motor phenotype in future work.


Assuntos
Condicionamento Operante , Aprendizagem , Doença de Parkinson/fisiopatologia , Doença de Parkinson/psicologia , Idoso , Antiparkinsonianos/efeitos adversos , Antiparkinsonianos/uso terapêutico , Benserazida/efeitos adversos , Benserazida/uso terapêutico , Simulação por Computador , Agonistas de Dopamina/efeitos adversos , Agonistas de Dopamina/uso terapêutico , Combinação de Medicamentos , Feminino , Humanos , Levodopa/efeitos adversos , Levodopa/uso terapêutico , Masculino , Pessoa de Meia-Idade , Motivação , Fenótipo , Punição , Recompensa , Tremor/fisiopatologia
8.
Hum Brain Mapp ; 41(4): 1017-1029, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31721369

RESUMO

Parkinson's disease is characterized by bradykinesia, rigidity, and tremor. These symptoms have been related to an increased gamma-aminobutyric acid (GABA)ergic inhibitory drive from globus pallidus onto the thalamus. However, in vivo empirical evidence for the role of GABA in Parkinson's disease is limited. Some discrepancies in the literature may be explained by the presence or absence of tremor. Specifically, recent functional magnetic resonance imaging (fMRI) findings suggest that Parkinson's tremor is associated with reduced, dopamine-dependent thalamic inhibition. Here, we tested the hypothesis that GABA in the thalamocortical motor circuit is increased in Parkinson's disease, and we explored differences between clinical phenotypes. We included 60 Parkinson patients with dopamine-resistant tremor (n = 17), dopamine-responsive tremor (n = 23), or no tremor (n = 20), and healthy controls (n = 22). Using magnetic resonance spectroscopy, we measured GABA-to-total-creatine ratio in motor cortex, thalamus, and a control region (visual cortex) on two separate days (ON and OFF dopaminergic medication). GABA levels were unaltered by Parkinson's disease, clinical phenotype, or medication. However, motor cortex GABA levels were inversely correlated with disease severity, particularly rigidity and tremor, both ON and OFF medication. We conclude that cortical GABA plays a beneficial rather than a detrimental role in Parkinson's disease, and that GABA depletion may contribute to increased motor symptom expression.


Assuntos
Córtex Motor/metabolismo , Rigidez Muscular/metabolismo , Rede Nervosa/metabolismo , Doença de Parkinson/metabolismo , Tálamo/metabolismo , Tremor/metabolismo , Ácido gama-Aminobutírico/metabolismo , Idoso , Creatina/metabolismo , Dopaminérgicos/farmacologia , Feminino , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Córtex Motor/diagnóstico por imagem , Rigidez Muscular/diagnóstico por imagem , Rigidez Muscular/etiologia , Rede Nervosa/diagnóstico por imagem , Doença de Parkinson/complicações , Doença de Parkinson/diagnóstico por imagem , Tálamo/diagnóstico por imagem , Tremor/diagnóstico por imagem , Tremor/tratamento farmacológico , Tremor/etiologia
9.
J Cogn Neurosci ; 30(10): 1379-1390, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29244641

RESUMO

To survive in complex environments, animals need to have mechanisms to select effective actions quickly, with minimal computational costs. As perhaps the computationally most parsimonious of these systems, Pavlovian control accomplishes this by hardwiring specific stereotyped responses to certain classes of stimuli. It is well documented that appetitive cues initiate a Pavlovian bias toward vigorous approach; however, Pavlovian responses to aversive stimuli are less well understood. Gaining a deeper understanding of aversive Pavlovian responses, such as active avoidance, is important given the critical role these behaviors play in several psychiatric conditions. The goal of the current study was to establish a behavioral and computational framework to examine aversive Pavlovian responses (activation vs. inhibition) depending on the proximity of an aversive state (escape vs. avoidance). We introduce a novel task in which participants are exposed to primary aversive (noise) stimuli and characterized behavior using a novel generative computational model. This model combines reinforcement learning and drift-diffusion models so as to capture effects of invigoration/inhibition in both explicit choice behavior as well as changes in RT. Choice and RT results both suggest that escape is associated with a bias for vigorous action, whereas avoidance is associated with behavioral inhibition. These results lay a foundation for future work seeking insights into typical and atypical aversive Pavlovian responses involved in psychiatric disorders, allowing us to quantify both implicit and explicit indices of vigorous choice behavior in the context of aversion.


Assuntos
Aprendizagem da Esquiva/fisiologia , Comportamento de Escolha/fisiologia , Condicionamento Clássico/fisiologia , Reação de Fuga/fisiologia , Tempo de Reação/fisiologia , Reforço Psicológico , Estimulação Acústica/métodos , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
10.
Brain ; 140(3): 721-734, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28073788

RESUMO

Parkinson's resting tremor is related to altered cerebral activity in the basal ganglia and the cerebello-thalamo-cortical circuit. Although Parkinson's disease is characterized by dopamine depletion in the basal ganglia, the dopaminergic basis of resting tremor remains unclear: dopaminergic medication reduces tremor in some patients, but many patients have a dopamine-resistant tremor. Using pharmacological functional magnetic resonance imaging, we test how a dopaminergic intervention influences the cerebral circuit involved in Parkinson's tremor. From a sample of 40 patients with Parkinson's disease, we selected 15 patients with a clearly tremor-dominant phenotype. We compared tremor-related activity and effective connectivity (using combined electromyography-functional magnetic resonance imaging) on two occasions: ON and OFF dopaminergic medication. Building on a recently developed cerebral model of Parkinson's tremor, we tested the effect of dopamine on cerebral activity associated with the onset of tremor episodes (in the basal ganglia) and with tremor amplitude (in the cerebello-thalamo-cortical circuit). Dopaminergic medication reduced clinical resting tremor scores (mean 28%, range -12 to 68%). Furthermore, dopaminergic medication reduced tremor onset-related activity in the globus pallidus and tremor amplitude-related activity in the thalamic ventral intermediate nucleus. Network analyses using dynamic causal modelling showed that dopamine directly increased self-inhibition of the ventral intermediate nucleus, rather than indirectly influencing the cerebello-thalamo-cortical circuit through the basal ganglia. Crucially, the magnitude of thalamic self-inhibition predicted the clinical dopamine response of tremor. Dopamine reduces resting tremor by potentiating inhibitory mechanisms in a cerebellar nucleus of the thalamus (ventral intermediate nucleus). This suggests that altered dopaminergic projections to the cerebello-thalamo-cortical circuit have a role in Parkinson's tremor.aww331media15307619934001.


Assuntos
Cerebelo/efeitos dos fármacos , Dopaminérgicos/uso terapêutico , Vias Neurais/efeitos dos fármacos , Doença de Parkinson/complicações , Tálamo/efeitos dos fármacos , Tremor/patologia , Tremor/terapia , Teorema de Bayes , Mapeamento Encefálico , Cerebelo/diagnóstico por imagem , Dopaminérgicos/farmacologia , Eletromiografia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Vias Neurais/diagnóstico por imagem , Dinâmica não Linear , Oxigênio/sangue , Doença de Parkinson/diagnóstico por imagem , Índice de Gravidade de Doença , Tálamo/diagnóstico por imagem , Tremor/diagnóstico por imagem
11.
Cereb Cortex ; 27(1): 485-495, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-26494799

RESUMO

Interactions between motivational, cognitive, and motor regions of the striatum are crucial for implementing behavioral control. Work with experimental animals indicates that such interactions are sensitive to modulation by dopamine. Using systematic pharmacological manipulation of dopamine D2-receptors and resting-state functional imaging, we defined the functional architecture of the human striatum and quantified the effects of dopaminergic drugs on intrinsic effective connectivity between striatal subregions. We found that dopamine modulates interactions between motivational and cognitive regions, as well cognitive and motor regions of the striatum. Stimulation and blockade of the dopamine D2-receptor had opposite (increasing and decreasing) effects on the efficacy of those interactions. Furthermore, trait impulsivity was specifically associated with dopaminergic modulation of ventral-to-dorsal striatal connectivity. Individuals with high trait impulsivity exhibited greater drug-induced increases (after stimulation) and decreases (after blockade) of ventral-to-dorsal striatal connectivity than those with low trait impulsivity. These observations establish a key link between dopamine, intrinsic effective connectivity between striatal subregions, and trait impulsivity.


Assuntos
Corpo Estriado/metabolismo , Dopamina/metabolismo , Comportamento Impulsivo/fisiologia , Vias Neurais/metabolismo , Adolescente , Adulto , Corpo Estriado/anatomia & histologia , Corpo Estriado/efeitos dos fármacos , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/anatomia & histologia , Vias Neurais/efeitos dos fármacos , Adulto Jovem
12.
J Neurosci ; 36(19): 5362-72, 2016 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-27170132

RESUMO

UNLABELLED: Parkinson's resting tremor has been linked to pathophysiological changes both in the basal ganglia and in a cerebello-thalamo-cortical motor loop, but the role of those circuits in initiating and maintaining tremor remains unclear. Here, we test whether and how the cerebello-thalamo-cortical loop is driven into a tremor-related state by virtue of its connectivity with the basal ganglia. An internal replication design on two independent cohorts of tremor-dominant Parkinson patients sampled brain activity and tremor with concurrent EMG-fMRI. Using dynamic causal modeling, we tested: (1) whether activity at the onset of tremor episodes drives tremulous network activity through the basal ganglia or the cerebello-thalamo-cortical loop and (2) whether the basal ganglia influence the cerebello-thalamo-cortical loop through connectivity with the cerebellum or motor cortex. We compared five physiologically plausible circuits, model families in which transient activity at the onset of tremor episodes (assessed using EMG) drove network activity through the internal globus pallidus (GPi), external globus pallidus, motor cortex, thalamus, or cerebellum. In each family, we compared two models in which the basal ganglia and cerebello-thalamo-cortical loop were connected through the cerebellum or motor cortex. In both cohorts, cerebral activity associated with changes in tremor amplitude (using peripheral EMG measures as a proxy for tremor-related neuronal activity) drove network activity through the GPi, which effectively influenced the cerebello-thalamo-cortical loop through the motor cortex. We conclude that cerebral activity related to Parkinson's tremor first arises in the GPi and is then propagated to the cerebello-thalamo-cortical circuit. SIGNIFICANCE STATEMENT: Parkinson's resting tremor has been linked to pathophysiological changes both in the basal ganglia and in a cerebello-thalamo-cortical motor loop, but the role of those circuits in initiating and maintaining tremor remains unclear. Using dynamic causal modeling of concurrently collected EMG-fMRI data in two cohorts of Parkinson's patients, we showed that cerebral activity associated with changes in tremor amplitude drives network activity through the basal ganglia. Furthermore, the basal ganglia effectively influenced the cerebello-thalamo-cortical circuit through the motor cortex (but not the cerebellum). Out findings suggest that Parkinson's tremor-related activity first arises in the basal ganglia and is then propagated to the cerebello-thalamo-cortical circuit.


Assuntos
Gânglios da Base/fisiopatologia , Conectoma , Córtex Motor/fisiopatologia , Transtornos Parkinsonianos/fisiopatologia , Tremor/fisiopatologia , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos Parkinsonianos/diagnóstico por imagem , Tremor/diagnóstico por imagem
13.
Neuroimage ; 125: 556-570, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26484827

RESUMO

High-resolution blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) at the sub-millimeter scale has become feasible with recent advances in MR technology. In principle, this would enable the study of layered cortical circuits, one of the fundaments of cortical computation. However, the spatial layout of cortical blood supply may become an important confound at such high resolution. In particular, venous blood draining back to the cortical surface perpendicularly to the layered structure is expected to influence the measured responses in different layers. Here, we present an extension of a hemodynamic model commonly used for analyzing fMRI data (in dynamic causal models or biophysical network models) that accounts for such blood draining effects by coupling local hemodynamics across layers. We illustrate the properties of the model and its inversion by a series of simulations and show that it successfully captures layered fMRI data obtained during a simple visual experiment. We conclude that for future studies of the dynamics of layered neuronal circuits with high-resolution fMRI, it will be pivotal to include effects of blood draining, particularly when trying to infer on the layer-specific connections in cortex--a theme of key relevance for brain disorders like schizophrenia and for theories of brain function such as predictive coding.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/irrigação sanguínea , Hemodinâmica/fisiologia , Imageamento por Ressonância Magnética/métodos , Modelos Neurológicos , Algoritmos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Modelos Teóricos , Oxigênio/sangue
14.
Cereb Cortex ; 25(6): 1527-34, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24343891

RESUMO

The prefrontal cortex and the basal ganglia interact to selectively gate a desired action. Recent studies have shown that this selective gating mechanism of the basal ganglia extends to the domain of attention. Here, we investigate the nature of this action-like gating mechanism for attention using a spatial attention-switching paradigm in combination with functional neuroimaging and dynamic causal modeling. We show that the basal ganglia guide attention by focally releasing inhibition of task-relevant representations, while simultaneously inhibiting task-irrelevant representations by selectively modulating prefrontal top-down connections. These results strengthen and specify the role of the basal ganglia in attention. Moreover, our findings have implications for psychological theorizing by suggesting that inhibition of unattended sensory regions is not only a consequence of mutual suppression, but is an active process, subserved by the basal ganglia.


Assuntos
Atenção/fisiologia , Gânglios da Base/fisiologia , Inibição Psicológica , Vias Neurais/fisiologia , Córtex Pré-Frontal/fisiologia , Adolescente , Adulto , Gânglios da Base/irrigação sanguínea , Feminino , Lateralidade Funcional , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Modelos Biológicos , Vias Neurais/irrigação sanguínea , Testes Neuropsicológicos , Dinâmica não Linear , Oxigênio/sangue , Córtex Pré-Frontal/irrigação sanguínea , Tempo de Reação , Campos Visuais/fisiologia , Adulto Jovem
15.
J Neurosci ; 33(48): 18932-9, 2013 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-24285898

RESUMO

Adaptive decision-making involves interaction between systems regulating Pavlovian and instrumental control of behavior. Here we investigate in humans the role of serotonin in such Pavlovian-instrumental transfer in both the aversive and the appetitive domain using acute tryptophan depletion, known to lower central serotonin levels. Acute tryptophan depletion attenuated the inhibiting effect of aversive Pavlovian cues on instrumental behavior, while leaving unaltered the activating effect of appetitive Pavlovian cues. These data suggest that serotonin is selectively involved in Pavlovian inhibition due to aversive expectations and have implications for our understanding of the mechanisms underlying a range of affective, impulsive, and aggressive neuropsychiatric disorders.


Assuntos
Comportamento/fisiologia , Condicionamento Clássico/fisiologia , Serotonina/fisiologia , Adolescente , Adulto , Afeto/fisiologia , Aminoácidos/metabolismo , Apetite/fisiologia , Sinais (Psicologia) , Interpretação Estatística de Dados , Tomada de Decisões , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Testes de Personalidade , Psicometria , Desempenho Psicomotor/fisiologia , Reforço Psicológico , Neurônios Serotoninérgicos/fisiologia , Serotonina/sangue , Triptofano/sangue , Triptofano/deficiência , Triptofano/fisiologia , Adulto Jovem
16.
J Neurosci ; 33(21): 8974-9, 2013 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-23699508

RESUMO

After a threatening event, the risk of developing social psychopathologies is increased in short-allele (s) carriers of the serotonin transporter gene. The amygdala becomes overresponsive to emotional stimuli, an effect that could be driven by local hypersensitivity or by reduced prefrontal regulation. This study distinguishes between these two hypotheses by using dynamic causal modeling of fMRI data acquired in a preselected cohort of human s-carriers and homozygous long-allele carriers. Increased amygdala activity in s-carriers originates from reduced prefrontal inhibitory regulation when social emotional behavior needs to be controlled, suggesting a mechanism for increased vulnerability to psychopathologies.


Assuntos
Tonsila do Cerebelo/fisiologia , Emoções/fisiologia , Córtex Pré-Frontal/fisiologia , Proteínas da Membrana Plasmática de Transporte de Serotonina/genética , Adulto , Tonsila do Cerebelo/irrigação sanguínea , Análise de Variância , Estudos de Coortes , Método Duplo-Cego , Genótipo , Heterozigoto , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/irrigação sanguínea , Vias Neurais/fisiologia , Oxigênio/sangue , Reconhecimento Visual de Modelos , Estimulação Luminosa , Polimorfismo Genético/genética , Córtex Pré-Frontal/irrigação sanguínea , Tempo de Reação/genética , Saliva/metabolismo , Adulto Jovem
17.
Nat Commun ; 15(1): 19, 2024 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-38168089

RESUMO

Actions are biased by the outcomes they can produce: Humans are more likely to show action under reward prospect, but hold back under punishment prospect. Such motivational biases derive not only from biased response selection, but also from biased learning: humans tend to attribute rewards to their own actions, but are reluctant to attribute punishments to having held back. The neural origin of these biases is unclear. Specifically, it remains open whether motivational biases arise primarily from the architecture of subcortical regions or also reflect cortical influences, the latter being typically associated with increased behavioral flexibility and control beyond stereotyped behaviors. Simultaneous EEG-fMRI allowed us to track which regions encoded biased prediction errors in which order. Biased prediction errors occurred in cortical regions (dorsal anterior and posterior cingulate cortices) before subcortical regions (striatum). These results highlight that biased learning is not a mere feature of the basal ganglia, but arises through prefrontal cortical contributions, revealing motivational biases to be a potentially flexible, sophisticated mechanism.


Assuntos
Corpo Estriado , Aprendizagem , Humanos , Aprendizagem/fisiologia , Corpo Estriado/diagnóstico por imagem , Corpo Estriado/fisiologia , Neostriado , Recompensa , Imageamento por Ressonância Magnética , Tomada de Decisões/fisiologia , Viés
18.
Elife ; 122024 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-39190585

RESUMO

Transcranial ultrasonic stimulation (TUS) is rapidly emerging as a promising non-invasive neuromodulation technique. TUS is already well-established in animal models, providing foundations to now optimize neuromodulatory efficacy for human applications. Across multiple studies, one promising protocol, pulsed at 1000 Hz, has consistently resulted in motor cortical inhibition in humans (Fomenko et al., 2020). At the same time, a parallel research line has highlighted the potentially confounding influence of peripheral auditory stimulation arising from TUS pulsing at audible frequencies. In this study, we disentangle direct neuromodulatory and indirect auditory contributions to motor inhibitory effects of TUS. To this end, we include tightly matched control conditions across four experiments, one preregistered, conducted independently at three institutions. We employed a combined transcranial ultrasonic and magnetic stimulation paradigm, where TMS-elicited motor-evoked potentials (MEPs) served as an index of corticospinal excitability. First, we replicated motor inhibitory effects of TUS but showed through both tight controls and manipulation of stimulation intensity, duration, and auditory masking conditions that this inhibition was driven by peripheral auditory stimulation, not direct neuromodulation. Furthermore, we consider neuromodulation beyond driving overall excitation/inhibition and show preliminary evidence of how TUS might interact with ongoing neural dynamics instead. Primarily, this study highlights the substantial shortcomings in accounting for the auditory confound in prior TUS-TMS work where only a flip-over sham and no active control was used. The field must critically reevaluate previous findings given the demonstrated impact of peripheral confounds. Furthermore, rigorous experimental design via (in)active control conditions is required to make substantiated claims in future TUS studies. Only when direct effects are disentangled from those driven by peripheral confounds can TUS fully realize its potential for research and clinical applications.


Assuntos
Estimulação Acústica , Potencial Evocado Motor , Córtex Motor , Estimulação Magnética Transcraniana , Humanos , Adulto , Feminino , Masculino , Estimulação Magnética Transcraniana/métodos , Potencial Evocado Motor/fisiologia , Córtex Motor/fisiologia , Adulto Jovem , Ondas Ultrassônicas
19.
J Cogn Neurosci ; 25(9): 1428-41, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23691985

RESUMO

Adaptive behavior involves interactions between systems regulating Pavlovian and instrumental control of actions. Here, we present the first investigation of the neural mechanisms underlying aversive Pavlovian-instrumental transfer using fMRI in humans. Recent evidence indicates that these Pavlovian influences on instrumental actions are action-specific: Instrumental approach is invigorated by appetitive Pavlovian cues but inhibited by aversive Pavlovian cues. Conversely, instrumental withdrawal is inhibited by appetitive Pavlovian cues but invigorated by aversive Pavlovian cues. We show that BOLD responses in the amygdala and the nucleus accumbens were associated with behavioral inhibition by aversive Pavlovian cues, irrespective of action context. Furthermore, BOLD responses in the ventromedial prefrontal cortex differed between approach and withdrawal actions. Aversive Pavlovian conditioned stimuli modulated connectivity between the ventromedial prefrontal cortex and the caudate nucleus. These results show that action-specific aversive control of instrumental behavior involves the modulation of fronto-striatal interactions by Pavlovian conditioned stimuli.


Assuntos
Aprendizagem da Esquiva/fisiologia , Encéfalo/fisiologia , Condicionamento Clássico/fisiologia , Condicionamento Operante/fisiologia , Adaptação Psicológica , Adulto , Análise de Variância , Encéfalo/irrigação sanguínea , Feminino , Generalização Psicológica , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Oxigênio/sangue , Estimulação Luminosa , Transferência de Experiência , Adulto Jovem
20.
J Exp Psychol Gen ; 152(10): 2941-2956, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37199975

RESUMO

Prospective outcomes bias behavior in a "Pavlovian" manner: Reward prospect invigorates action, while punishment prospect suppresses it. Theories have posited Pavlovian biases as global action "priors" in unfamiliar or uncontrollable environments. However, this account fails to explain the strength of these biases-causing frequent action slips-even in well-known environments. We propose that Pavlovian control is additionally useful if flexibly recruited by instrumental control. Specifically, instrumental action plans might shape selective attention to reward/punishment information and thus the input to Pavlovian control. In two eye-tracking samples (N = 35/64), we observed that Go/NoGo action plans influenced when and for how long participants attended to reward/punishment information, which in turn biased their responses in a Pavlovian manner. Participants with stronger attentional effects showed higher performance. Thus, humans appear to align Pavlovian control with their instrumental action plans, extending its role beyond action defaults to a powerful tool ensuring robust action execution. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Assuntos
Objetivos , Motivação , Humanos , Estudos Prospectivos , Recompensa , Viés
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