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1.
Neuroimage ; 181: 807-813, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-29729393

RESUMO

Neurofeedback - learning to modulate brain function through real-time monitoring of current brain state - is both a powerful method to perturb and probe brain function and an exciting potential clinical tool. For neurofeedback effects to be useful clinically, they must persist. Here we examine the time course of symptom change following neurofeedback in two clinical populations, combining data from two ongoing neurofeedback studies. This analysis reveals a shared pattern of symptom change, in which symptoms continue to improve for weeks after neurofeedback. This time course has several implications for future neurofeedback studies. Most neurofeedback studies are not designed to test an intervention with this temporal pattern of response. We recommend that new studies incorporate regular follow-up of subjects for weeks or months after the intervention to ensure that the time point of greatest effect is sampled. Furthermore, this time course of continuing clinical change has implications for crossover designs, which may attribute long-term, ongoing effects of real neurofeedback to the control intervention that follows. Finally, interleaving neurofeedback sessions with assessments and examining when clinical improvement peaks may not be an appropriate approach to determine the optimal number of sessions for an application.


Assuntos
Neuroimagem Funcional/métodos , Imageamento por Ressonância Magnética/métodos , Terapias Mente-Corpo/métodos , Neurorretroalimentação/fisiologia , Transtorno Obsessivo-Compulsivo/terapia , Avaliação de Resultados em Cuidados de Saúde , Reconhecimento Visual de Modelos/fisiologia , Córtex Pré-Frontal/fisiopatologia , Síndrome de Tourette/terapia , Adolescente , Adulto , Humanos , Pessoa de Meia-Idade , Córtex Pré-Frontal/diagnóstico por imagem , Fatores de Tempo
2.
JAMA Psychiatry ; 72(9): 882-91, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26267151

RESUMO

IMPORTANCE: Severe neuropsychiatric conditions, such as schizophrenia, affect distributed neural computations. One candidate system profoundly altered in chronic schizophrenia involves the thalamocortical networks. It is widely acknowledged that schizophrenia is a neurodevelopmental disorder that likely affects the brain before onset of clinical symptoms. However, no investigation has tested whether thalamocortical connectivity is altered in individuals at risk for psychosis or whether this pattern is more severe in individuals who later develop full-blown illness. OBJECTIVES: To determine whether baseline thalamocortical connectivity differs between individuals at clinical high risk for psychosis and healthy controls, whether this pattern is more severe in those who later convert to full-blown illness, and whether magnitude of thalamocortical dysconnectivity is associated with baseline prodromal symptom severity. DESIGN, SETTING, AND PARTICIPANTS: In this multicenter, 2-year follow-up, case-control study, we examined 397 participants aged 12-35 years of age (243 individuals at clinical high risk of psychosis, of whom 21 converted to full-blown illness, and 154 healthy controls). The baseline scan dates were January 15, 2010, to April 30, 2012. MAIN OUTCOMES AND MEASURES: Whole-brain thalamic functional connectivity maps were generated using individuals' anatomically defined thalamic seeds, measured using resting-state functional connectivity magnetic resonance imaging. RESULTS: Using baseline magnetic resonance images, we identified thalamocortical dysconnectivity in the 243 individuals at clinical high risk for psychosis, which was particularly pronounced in the 21 participants who converted to full-blown illness. The pattern involved widespread hypoconnectivity between the thalamus and prefrontal and cerebellar areas, which was more prominent in those who converted to full-blown illness (t(173) = 3.77, P < .001, Hedge g = 0.88). Conversely, there was marked thalamic hyperconnectivity with sensory motor areas, again most pronounced in those who converted to full-blown illness (t(173) = 2.85, P < .001, Hedge g = 0.66). Both patterns were significantly correlated with concurrent prodromal symptom severity (r = 0.27, P < 3.6 × 10(-8), Spearman ρ = 0.27, P < 4.75 × 10(-5), 2-tailed). CONCLUSIONS AND RELEVANCE: Thalamic dysconnectivity, resembling that seen in schizophrenia, was evident in individuals at clinical high risk for psychosis and more prominently in those who later converted to psychosis. Dysconnectivity correlated with symptom severity, supporting the idea that thalamic connectivity may have prognostic implications for risk of conversion to full-blown illness.


Assuntos
Cerebelo/fisiopatologia , Córtex Cerebral/fisiopatologia , Sintomas Prodrômicos , Transtornos Psicóticos/fisiopatologia , Esquizofrenia/fisiopatologia , Tálamo/fisiopatologia , Adolescente , Adulto , Mapeamento Encefálico , Estudos de Casos e Controles , Criança , Progressão da Doença , Feminino , Seguimentos , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/fisiopatologia , Risco , Adulto Jovem
3.
J Vis Exp ; (59)2012 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-22297729

RESUMO

We present a method for training subjects to control activity in a region of their orbitofrontal cortex associated with contamination anxiety using biofeedback of real-time functional magnetic resonance imaging (rt-fMRI) data. Increased activity of this region is seen in relationship with contamination anxiety both in control subjects and in individuals with obsessive-compulsive disorder (OCD), a relatively common and often debilitating psychiatric disorder involving contamination anxiety. Although many brain regions have been implicated in OCD, abnormality in the orbitofrontal cortex (OFC) is one of the most consistent findings. Furthermore, hyperactivity in the OFC has been found to correlate with OCD symptom severity and decreases in hyperactivity in this region have been reported to correlate with decreased symptom severity. Therefore, the ability to control this brain area may translate into clinical improvements in obsessive-compulsive symptoms including contamination anxiety. Biofeedback of rt-fMRI data is a new technique in which the temporal pattern of activity in a specific region (or associated with a specific distributed pattern of brain activity) in a subject's brain is provided as a feedback signal to the subject. Recent reports indicate that people are able to develop control over the activity of specific brain areas when provided with rt-fMRI biofeedback. In particular, several studies using this technique to target brain areas involved in emotion processing have reported success in training subjects to control these regions. In several cases, rt-fMRI biofeedback training has been reported to induce cognitive, emotional, or clinical changes in subjects. Here we illustrate this technique as applied to the treatment of contamination anxiety in healthy subjects. This biofeedback intervention will be a valuable basic research tool: it allows researchers to perturb brain function, measure the resulting changes in brain dynamics and relate those to changes in contamination anxiety or other behavioral measures. In addition, the establishment of this method serves as a first step towards the investigation of fMRI-based biofeedback as a therapeutic intervention for OCD. Given that approximately a quarter of patients with OCD receive little benefit from the currently available forms of treatment, and that those who do benefit rarely recover completely, new approaches for treating this population are urgently needed.


Assuntos
Ansiedade/fisiopatologia , Lobo Frontal/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Transtorno Obsessivo-Compulsivo/fisiopatologia , Biorretroalimentação Psicológica/fisiologia , Sistemas Computacionais , Humanos
4.
Brain Connect ; 1(1): 91-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22432958

RESUMO

Recent studies have reported that biofeedback of real-time functional magnetic resonance imaging data can enable people to gain control of activity in specific parts of their brain and can alter functional connectivity between brain areas. Here we describe a study using biofeedback of real-time functional magnetic resonance imaging data to train healthy subjects to control activity in their supplementary motor area (SMA), a region of interest in Tourette syndrome (TS). Although a significant increase in control over the SMA during biofeedback was not found, subjects were able to exert significant control over the SMA in later biofeedback sessions despite not having control in the first biofeedback session. Further, changes were found in their resting state functional connectivity. Specifically, when comparing functional connectivity to the SMA before and after biofeedback, the strength of functional connectivity with subcortical regions was reduced after the biofeedback. This suggests that biofeedback may allow subjects to develop greater conscious control over activity in their SMA by reducing the influence of corticostriatothalamocortical loops on the region. This possibility is promising for TS, where aberrant dynamics in corticostriatothalamocortical loops have long been suspected to give rise to tic symptoms. Further studies in TS patients are needed.


Assuntos
Biorretroalimentação Psicológica/métodos , Biorretroalimentação Psicológica/fisiologia , Sistemas Computacionais , Imageamento por Ressonância Magnética/métodos , Córtex Motor/fisiologia , Rede Nervosa/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vias Neurais/fisiologia , Estimulação Luminosa/métodos , Adulto Jovem
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