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1.
Front Psychiatry ; 14: 1250268, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38025434

RESUMO

Gut inflammation is thought to modify brain activity and behaviour via modulation of the gut-brain axis. However, how relapsing and remitting exposure to peripheral inflammation over the natural history of inflammatory bowel disease (IBD) contributes to altered brain dynamics is poorly understood. Here, we used electroencephalography (EEG) to characterise changes in spontaneous spatiotemporal brain states in Crohn's Disease (CD) (n = 40) and Ulcerative Colitis (UC) (n = 30), compared to healthy individuals (n = 28). We first provide evidence of a significantly perturbed and heterogeneous microbial profile in CD, consistent with previous work showing enduring and long-standing dysbiosis in clinical remission. Results from our brain state assessment show that CD and UC exhibit alterations in the temporal properties of states implicating default-mode network, parietal, and visual regions, reflecting a shift in the predominance from externally to internally-oriented attentional modes. We investigated these dynamics at a finer sub-network resolution, showing a CD-specific and highly selective enhancement of connectivity between the insula and medial prefrontal cortex (mPFC), regions implicated in cognitive-interoceptive appraisal mechanisms. Alongside overall higher anxiety scores in CD, we also provide preliminary support to suggest that the strength of chronic interoceptive hyper-signalling in the brain co-occurs with disease duration. Together, our results demonstrate that a long-standing diagnosis of CD is, in itself, a key factor in determining the risk of developing altered brain network signatures.

2.
Hum Brain Mapp ; 44(18): 6418-6428, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37853935

RESUMO

Current behavioural treatment of obsessive-compulsive disorder (OCD) is informed by fear conditioning and involves iteratively re-evaluating previously threatening stimuli as safe. However, there is limited research investigating the neurobiological response to conditioning and reversal of threatening stimuli in individuals with OCD. A clinical sample of individuals with OCD (N = 45) and matched healthy controls (N = 45) underwent functional magnetic resonance imaging. While in the scanner, participants completed a well-validated fear reversal task and a resting-state scan. We found no evidence for group differences in task-evoked brain activation or functional connectivity in OCD. Multivariate analyses encompassing all participants in the clinical and control groups suggested that subjective appraisal of threatening and safe stimuli were associated with a larger difference in brain activity than the contribution of OCD symptoms. In particular, we observed a brain-behaviour continuum whereby heightened affective appraisal was related to increased bilateral insula activation during the task (r = 0.39, pFWE = .001). These findings suggest that changes in conditioned threat-related processes may not be a core neurobiological feature of OCD and encourage further research on the role of subjective experience in fear conditioning.


Assuntos
Transtorno Obsessivo-Compulsivo , Humanos , Medo/fisiologia , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Córtex Insular , Mapeamento Encefálico
3.
Netw Neurosci ; 7(2): 557-577, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37397892

RESUMO

The dynamic integration of sensory and bodily signals is central to adaptive behaviour. Although the anterior cingulate cortex (ACC) and the anterior insular cortex (AIC) play key roles in this process, their context-dependent dynamic interactions remain unclear. Here, we studied the spectral features and interplay of these two brain regions using high-fidelity intracranial-EEG recordings from five patients (ACC: 13 contacts, AIC: 14 contacts) acquired during movie viewing with validation analyses performed on an independent resting intracranial-EEG dataset. ACC and AIC both showed a power peak and positive functional connectivity in the gamma (30-35 Hz) frequency while this power peak was absent in the resting data. We then used a neurobiologically informed computational model investigating dynamic effective connectivity asking how it linked to the movie's perceptual (visual, audio) features and the viewer's heart rate variability (HRV). Exteroceptive features related to effective connectivity of ACC highlighting its crucial role in processing ongoing sensory information. AIC connectivity was related to HRV and audio emphasising its core role in dynamically linking sensory and bodily signals. Our findings provide new evidence for complementary, yet dissociable, roles of neural dynamics between the ACC and the AIC in supporting brain-body interactions during an emotional experience.

4.
Elife ; 122023 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-37226880

RESUMO

External tasks evoke characteristic fMRI BOLD signal deactivations in the default mode network (DMN). However, for the corresponding metabolic glucose demands both decreases and increases have been reported. To resolve this discrepancy, functional PET/MRI data from 50 healthy subjects performing Tetris were combined with previously published data sets of working memory, visual and motor stimulation. We show that the glucose metabolism of the posteromedial DMN is dependent on the metabolic demands of the correspondingly engaged task-positive networks. Specifically, the dorsal attention and frontoparietal network shape the glucose metabolism of the posteromedial DMN in opposing directions. While tasks that mainly require an external focus of attention lead to a consistent downregulation of both metabolism and the BOLD signal in the posteromedial DMN, cognitive control during working memory requires a metabolically expensive BOLD suppression. This indicates that two types of BOLD deactivations with different oxygen-to-glucose index may occur in this region. We further speculate that consistent downregulation of the two signals is mediated by decreased glutamate signaling, while divergence may be subject to active GABAergic inhibition. The results demonstrate that the DMN relates to cognitive processing in a flexible manner and does not always act as a cohesive task-negative network in isolation.


Assuntos
Mapeamento Encefálico , Encéfalo , Humanos , Encéfalo/fisiologia , Rede de Modo Padrão , Memória de Curto Prazo/fisiologia , Atenção/fisiologia , Imageamento por Ressonância Magnética/métodos , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia
5.
Transl Psychiatry ; 13(1): 77, 2023 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-36864034

RESUMO

The mixed cognitive outcomes in early psychosis (EP) have important implications for recovery. In this longitudinal study, we asked whether baseline differences in the cognitive control system (CCS) in EP participants would revert toward a normative trajectory seen in healthy controls (HC). Thirty EP and 30 HC undertook functional MRI at baseline using the multi-source interference task-a paradigm that selectively introduces stimulus conflict-and 19 in each group repeated the task at 12 months. Activation of the left superior parietal cortex normalized over time for the EP group, relative to HC, coincident with improvements in reaction time and social-occupational functioning. To examine these group and timepoint differences, we used dynamic causal modeling to infer changes in effective connectivity between regions underlying the MSIT task execution, namely visual, anterior insula, anterior cingulate, and superior parietal cortical regions. To resolve stimulus conflict, EP participants transitioned from an indirect to a direct neuromodulation of sensory input to the anterior insula over timepoints, though not as strongly as HC participants. Stronger direct nonlinear modulation of the anterior insula by the superior parietal cortex at follow-up was associated with improved task performance. Overall, normalization of the CCS through adoption of more direct processing of complex sensory input to the anterior insula, was observed in EP after 12 months of treatment. Such processing of complex sensory input reflects a computational principle called gain control, which appears to track changes in cognitive trajectory within the EP group.


Assuntos
Transtornos Psicóticos , Humanos , Adulto Jovem , Cognição , Giro do Cíngulo , Estudos Longitudinais , Transtornos Psicóticos/diagnóstico por imagem
6.
Schizophr Bull ; 49(4): 987-996, 2023 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-36866458

RESUMO

BACKGROUND AND HYPOTHESIS: Impairments in the expression, experience, and recognition of emotion are common in early psychosis (EP). Computational accounts of psychosis suggest disrupted top-down modulation by the cognitive control system (CCS) on perceptual circuits underlies psychotic experiences, but their role in emotional deficits in EP is unknown. STUDY DESIGN: The affective go/no-go task was used to probe inhibitory control during the presentation of calm or fearful faces in young persons with EP and matched controls. Computational modeling of functional magnetic resonance imaging (fMRI) data were performed using dynamic causal modeling (DCM). The influence of the CCS on perceptual and emotional systems was examined using parametric empirical bayes. STUDY RESULTS: When inhibiting motor response to fearful faces, EP participants showed higher brain activity in the right posterior insula (PI). To explain this, we used DCM to model effective connectivity between the PI, regions from the CCS activated during inhibition (dorsolateral prefrontal cortex [DLPFC] and anterior insula [AI]), and a visual input region, the lateral occipital cortex (LOC). EP participants exerted a stronger top-down inhibition from the DLPFC to the LOC than controls. Within the EP cohort, increased top-down connectivity between the LOC and AI was associated with a higher burden of negative symptoms. CONCLUSIONS: Young persons with a recent onset of psychosis show a disturbance in the cognitive control of emotionally salient stimuli and the suppression of irrelevant distractors. These changes are associated with negative symptoms, suggesting new targets for the remediation of emotional deficits in young persons with EP.


Assuntos
Córtex Pré-Frontal , Transtornos Psicóticos , Humanos , Teorema de Bayes , Mapeamento Encefálico , Emoções/fisiologia , Transtornos Psicóticos/diagnóstico por imagem , Cognição/fisiologia , Imageamento por Ressonância Magnética
7.
Neuroimage Clin ; 37: 103324, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36638598

RESUMO

Following the published behavioral and cognitive results of this single-blind parallel sham-controlled randomized clinical trial, the current study aimed to explore the impact of intermittent theta burst stimulation (iTBS), a variant of excitatory transcranial magnetic stimulation, over the bilateral posterior superior temporal sulci (pSTS) on white matter macro/microstructure in intellectually able children and adolescents with autism. Participants were randomized and blindly received active or sham iTBS for 4 weeks (the single-blind sham-controlled phase). Then, all participants continued to receive active iTBS for another 4 weeks (the open-label phase). The clinical results were published elsewhere. Here, we present diffusion magnetic resonance imaging data on potential changes in white matter measures after iTBS. Twenty-two participants in Active-Active group and 27 participants in Sham-Active group underwent multi-shell high angular resolution diffusion imaging (64-direction for b = 2000 & 1000 s/mm2, respectively) at baseline, week 4, and week 8. With longitudinal fixel-based analysis, we found no white matter changes following iTBS from baseline to week 4 (a null treatment by time interaction and a null within-group paired comparison in the Active-Active group), nor from baseline to week 8 (null within-group paired comparisons in both Active-Active and Sham-Active groups). As for the brain-symptoms relationship, we did not find baseline white matter metrics associated with symptom changes at week 4 in either group. Our results raise the question of what the minimal cumulative stimulation dose required to induce the white matter plasticity is.


Assuntos
Transtorno Autístico , Estimulação Magnética Transcraniana , Humanos , Adolescente , Criança , Estimulação Magnética Transcraniana/métodos , Transtorno Autístico/diagnóstico por imagem , Método Simples-Cego , Ritmo Teta/fisiologia , Encéfalo/diagnóstico por imagem
8.
Brain ; 146(4): 1322-1327, 2023 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-36380526

RESUMO

The diagnosis of obsessive-compulsive disorder (OCD) has been linked with changes in frontostriatal resting-state connectivity. However, replication of prior findings is lacking, and the mechanistic understanding of these effects is incomplete. To confirm and advance knowledge on changes in frontostriatal functional connectivity in OCD, participants with OCD and matched healthy controls underwent resting-state functional, structural and diffusion neuroimaging. Functional connectivity changes in frontostriatal systems were here replicated in individuals with OCD (n = 52) compared with controls (n = 45). OCD participants showed greater functional connectivity (t = 4.3, PFWE = 0.01) between the nucleus accumbens (NAcc) and the orbitofrontal cortex (OFC) but lower functional connectivity between the dorsal putamen and lateral prefrontal cortex (t = 3.8, PFWE = 0.04) relative to controls. Computational modelling suggests that NAcc-OFC connectivity changes reflect an increased influence of NAcc over OFC activity and reduced OFC influence over NAcc activity (posterior probability, Pp > 0.66). Conversely, dorsal putamen showed reduced modulation over lateral prefrontal cortex activity (Pp > 0.90). These functional deregulations emerged on top of a generally intact anatomical substrate. We provide out-of-sample replication of opposite changes in ventro-anterior and dorso-posterior frontostriatal connectivity in OCD and advance the understanding of the neural underpinnings of these functional perturbations. These findings inform the development of targeted therapies normalizing frontostriatal dynamics in OCD.


Assuntos
Imageamento por Ressonância Magnética , Transtorno Obsessivo-Compulsivo , Humanos , Córtex Pré-Frontal/diagnóstico por imagem , Transtorno Obsessivo-Compulsivo/diagnóstico por imagem , Núcleo Accumbens , Putamen/diagnóstico por imagem , Mapeamento Encefálico
9.
Artigo em Inglês | MEDLINE | ID: mdl-36344036

Assuntos
Encéfalo , Humanos
10.
Elife ; 112022 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-36286251

RESUMO

The human brain is distinct from those of other species in terms of size, organization, and connectivity. How do structural evolutionary differences drive patterns of neural activity enabling brain function? Here, we combine brain imaging and biophysical modeling to show that the anatomical wiring of the human brain distinctly shapes neural dynamics. This shaping is characterized by a narrower distribution of dynamic ranges across brain regions compared with that of chimpanzees, our closest living primate relatives. We find that such a narrow dynamic range distribution supports faster integration between regions, particularly in transmodal systems. Conversely, a broad dynamic range distribution as seen in chimpanzees facilitates brain processes relying more on neural interactions within specialized local brain systems. These findings suggest that human brain dynamics have evolved to foster rapid associative processes in service of complex cognitive functions and behavior.


Assuntos
Conectoma , Humanos , Animais , Conectoma/métodos , Pan troglodytes , Encéfalo , Cognição , Evolução Biológica , Primatas , Imageamento por Ressonância Magnética/métodos , Rede Nervosa
11.
Mol Autism ; 13(1): 21, 2022 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-35585645

RESUMO

BACKGROUND: Neuroimage literature of autism spectrum disorder (ASD) has a moderate-to-high risk of bias, partially because those combined with intellectual impairment (II) and/or minimally verbal (MV) status are generally ignored. We aimed to provide more comprehensive insights into white matter alterations of ASD, inclusive of individuals with II (ASD-II-Only) or MV expression (ASD-MV). METHODS: Sixty-five participants with ASD (ASD-Whole; 16.6 ± 5.9 years; comprising 34 intellectually able youth, ASD-IA, and 31 intellectually impaired youth, ASD-II, including 24 ASD-II-Only plus 7 ASD-MV) and 38 demographic-matched typically developing controls (TDC; 17.3 ± 5.6 years) were scanned in accelerated diffusion-weighted MRI. Fixel-based analysis was undertaken to investigate the categorical differences in fiber density (FD), fiber cross section (FC), and a combined index (FDC), and brain symptom/cognition associations. RESULTS: ASD-Whole had reduced FD in the anterior and posterior corpus callosum and left cerebellum Crus I, and smaller FDC in right cerebellum Crus II, compared to TDC. ASD-IA, relative to TDC, had no significant discrepancies, while ASD-II showed almost identical alterations to those from ASD-Whole vs. TDC. ASD-II-Only had greater FD/FDC in the isthmus splenium of callosum than ASD-MV. Autistic severity negatively correlated with FC in right Crus I. Nonverbal full-scale IQ positively correlated with FC/FDC in cerebellum VI. FD/FDC of the right dorsolateral prefrontal cortex showed a diagnosis-by-executive function interaction. LIMITATIONS: We could not preclude the potential effects of age and sex from the ASD cohort, although statistical tests suggested that these factors were not influential. Our results could be confounded by variable psychiatric comorbidities and psychotropic medication uses in our ASD participants recruited from outpatient clinics, which is nevertheless closer to a real-world presentation of ASD. The outcomes related to ASD-MV were considered preliminaries due to the small sample size within this subgroup. Finally, our study design did not include intellectual impairment-only participants without ASD to disentangle the mixture of autistic and intellectual symptoms. CONCLUSIONS: ASD-associated white matter alterations appear driven by individuals with II and potentially further by MV. Results suggest that changes in the corpus callosum and cerebellum are key for psychopathology and cognition associated with ASD. Our work highlights an essential to include understudied subpopulations on the spectrum in research.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Substância Branca , Adolescente , Transtorno do Espectro Autista/diagnóstico por imagem , Transtorno do Espectro Autista/patologia , Transtorno Autístico/diagnóstico por imagem , Transtorno Autístico/patologia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Corpo Caloso/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Humanos , Substância Branca/diagnóstico por imagem , Substância Branca/patologia
12.
Nat Commun ; 13(1): 4, 2022 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-35013147

RESUMO

The emergence of distributed patterns of neural activity supporting brain functions and behavior can be understood by study of the brain's low-dimensional topology. Functional neuroimaging demonstrates that brain activity linked to adaptive behavior is constrained to low-dimensional manifolds. In human participants, we tested whether these low-dimensional constraints preserve working memory performance following local neuronal perturbations. We combined multi-session functional magnetic resonance imaging, non-invasive transcranial magnetic stimulation (TMS), and methods translated from the fields of complex systems and computational biology to assess the functional link between changes in local neural activity and the reshaping of task-related low dimensional trajectories of brain activity. We show that specific reconfigurations of low-dimensional trajectories of brain activity sustain effective working memory performance following TMS manipulation of local activity on, but not off, the space traversed by these trajectories. We highlight an association between the multi-scale changes in brain activity underpinning cognitive function.


Assuntos
Mapeamento Encefálico , Encéfalo/fisiologia , Cognição/fisiologia , Adolescente , Adulto , Mapeamento Encefálico/métodos , Feminino , Neuroimagem Funcional/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Memória de Curto Prazo/fisiologia , Estimulação Magnética Transcraniana/métodos
13.
Aust N Z J Psychiatry ; 56(8): 905-909, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-34969310

RESUMO

Following on from the publication of the Royal Australian and New Zealand Journal of Psychiatry Mood Disorder Clinical Practice Guidelines (2020) and criticisms of how these aberrantly addressed repetitive transcranial magnetic stimulation treatment of depression, questions have continued to be raised in the journal about this treatment by a small group of authors, whose views we contend do not reflect the broad acceptance of this treatment nationally and internationally. In fact, the evidence supporting the use of repetitive transcranial magnetic stimulation treatment in depression is unambiguous and substantial, consisting of an extensive series of clinical trials supported by multiple meta-analyses, network meta-analysis and umbrella reviews. Importantly, the use of repetitive transcranial magnetic stimulation treatment in depression has also been subject to a series of health economic analyses. These indicate that repetitive transcranial magnetic stimulation is a cost-effective therapy and have been used in some jurisdictions, including Australia, in support of public funding. An argument has been made that offering repetitive transcranial magnetic stimulation treatment may delay potentially effective pharmacotherapy. In fact, there is considerably greater danger of the opposite happening. Repetitive transcranial magnetic stimulation is as, if not more effective, than antidepressant medication after two unsuccessful medication trials and should be a consideration for all patients under these circumstances where available. There is no meaningful ongoing debate about the use of repetitive transcranial magnetic stimulation treatment in depression - it is a safe, effective and cost-effective treatment.


Assuntos
Depressão , Estimulação Magnética Transcraniana , Depressão/terapia , Humanos , Estimulação Magnética Transcraniana/efeitos adversos , Estimulação Magnética Transcraniana/economia , Resultado do Tratamento
14.
Cereb Cortex ; 32(11): 2385-2397, 2022 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-34585721

RESUMO

In utero brain development underpins brain health across the lifespan but is vulnerable to physiological and pharmacological perturbation. Here, we show that antiepileptic medication during pregnancy impacts on cortical activity during neonatal sleep, a potent indicator of newborn brain health. These effects are evident in frequency-specific functional brain networks and carry prognostic information for later neurodevelopment. Notably, such effects differ between different antiepileptic drugs that suggest neurodevelopmental adversity from exposure to antiepileptic drugs and not maternal epilepsy per se. This work provides translatable bedside metrics of brain health that are sensitive to the effects of antiepileptic drugs on postnatal neurodevelopment and carry direct prognostic value.


Assuntos
Epilepsia , Fenômenos Fisiológicos do Sistema Nervoso , Complicações na Gravidez , Efeitos Tardios da Exposição Pré-Natal , Anticonvulsivantes/efeitos adversos , Encéfalo , Epilepsia/tratamento farmacológico , Feminino , Humanos , Recém-Nascido , Gravidez , Complicações na Gravidez/tratamento farmacológico , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente
15.
Hum Brain Mapp ; 43(2): 733-749, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34811847

RESUMO

There is growing recognition that the composition of the gut microbiota influences behaviour, including responses to threat. The cognitive-interoceptive appraisal of threat-related stimuli relies on dynamic neural computations between the anterior insular (AIC) and the dorsal anterior cingulate (dACC) cortices. If, to what extent, and how microbial consortia influence the activity of this cortical threat processing circuitry is unclear. We addressed this question by combining a threat processing task, neuroimaging, 16S rRNA profiling and computational modelling in healthy participants. Results showed interactions between high-level ecological indices with threat-related AIC-dACC neural dynamics. At finer taxonomic resolutions, the abundance of Ruminococcus was differentially linked to connectivity between, and activity within the AIC and dACC during threat updating. Functional inference analysis provides a strong rationale to motivate future investigations of microbiota-derived metabolites in the observed relationship with threat-related brain processes.


Assuntos
Conectoma , Medo/fisiologia , Microbioma Gastrointestinal/fisiologia , Giro do Cíngulo/fisiologia , Córtex Insular/fisiologia , Rede Nervosa/fisiologia , Adulto , Condicionamento Clássico/fisiologia , Feminino , Giro do Cíngulo/diagnóstico por imagem , Humanos , Córtex Insular/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Modelos Teóricos , Rede Nervosa/diagnóstico por imagem , RNA Ribossômico 16S , Adulto Jovem
16.
Trials ; 22(1): 918, 2021 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-34903265

RESUMO

BACKGROUND: Schizophrenia is a persistent psychotic disorder often accompanied by severe disability and premature mortality. New pharmacological treatments are urgently needed. Sodium benzoate, a common food preservative holds potential to be an effective, accessible treatment for schizophrenia, though the optimal dosing and mechanism of action of the compound requires further investigation. METHODS: Individuals with persistent treatment-refractory schizophrenia (n=52) will be recruited. Patients will be randomised in a 1:1:1:1 ratio to receive treatment of one of three active doses (1000, 2000 or 4000 mg daily) of sodium benzoate or placebo for 6 weeks duration. The primary outcome measurement is change in the Positive and Negative Syndrome Scale (PANSS) total score. Secondary outcome measurements are PANSS subscales, Global Assessment of Function (GAF), Clinical Global Impression (CGI) and Patient Global Impression (PGI-I). Change in concentrations of peripheral amino acids (D-alanine, L-alanine, D-serine, L-serine, glycine and glutamate), plasma sodium benzoate, plasma catalase, 3-nitrotyrosine, malondialdehyde and high-sensitivity C-reactive protein (hs-CRP) will be determined as tertiary measures. DISCUSSION: This trial seeks to build upon previous research indicating potential efficacy of sodium benzoate for reduction of symptoms in individuals with treatment-refractory schizophrenia. The trial aims to improve the understanding of the mechanism of action of the compound. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12621000327886 . Registered on 23 March 2021.


Assuntos
Antipsicóticos , Esquizofrenia , Antipsicóticos/efeitos adversos , Austrália , Método Duplo-Cego , Humanos , Esquizofrenia/diagnóstico , Esquizofrenia/tratamento farmacológico , Esquizofrenia Resistente ao Tratamento , Benzoato de Sódio/efeitos adversos , Resultado do Tratamento
17.
Transl Psychiatry ; 11(1): 549, 2021 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-34707092

RESUMO

Executive dysfunctions in early psychosis (EP) are subtle but persistent, hindering recovery. We asked whether changes in the cognitive control system (CCS) disrupt the response to increased cognitive load in persons with EP. In all, 30 EP and 30 control participants undertook multimodal MRI. Computational models of structural and effective connectivity amongst regions in the CCS were informed by cortical responses to the multi-source interference task, a paradigm that selectively introduces stimulus conflict. EP participants showed greater activation of CCS regions, including the superior parietal cortex, and were disproportionately slower at resolving stimulus conflict in the task. Computational models of the effective connectivity underlying this behavioral response suggest that the normative (control) group resolved stimulus conflict through an efficient and direct modulation of gain between the visual cortex and the anterior insula (AI). In contrast, the EP group utilized an indirect path, with parallel and multi-region hops to resolve stimulus conflict at the AI. Individual differences in task performance were dependent on initial linear gain modulations in the EP group versus a single nonlinear modulation in the control group. Effective connectivity in the EP group was associated with reduced structural integration amongst those connections critical for task execution. CCS engagement during stimulus conflict is hampered in EP owing to inefficient use of higher-order network interactions, with high tonic gain impeding task-relevant (phasic) signal amplification.


Assuntos
Transtornos Psicóticos , Córtex Visual , Mapeamento Encefálico , Cognição , Humanos , Imageamento por Ressonância Magnética , Lobo Parietal , Transtornos Psicóticos/diagnóstico por imagem , Adulto Jovem
18.
Hum Brain Mapp ; 42(13): 4155-4172, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33544411

RESUMO

Repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) is an established treatment for refractory depression, however, therapeutic outcomes vary. Mounting evidence suggests that clinical response relates to functional connectivity with the subgenual cingulate cortex (SGC) at the precise DLPFC stimulation site. Critically, SGC-related network architecture shows considerable interindividual variation across the spatial extent of the DLPFC, indicating that connectivity-based target personalization could potentially be necessary to improve treatment outcomes. However, to date accurate personalization has not appeared feasible, with recent work indicating that the intraindividual reproducibility of optimal targets is limited to 3.5 cm. Here we developed reliable and accurate methodologies to compute individualized connectivity-guided stimulation targets. In resting-state functional MRI scans acquired across 1,000 healthy adults, we demonstrate that, using this approach, personalized targets can be reliably and robustly pinpointed, with a median accuracy of ~2 mm between scans repeated across separate days. These targets remained highly stable, even after 1 year, with a median intraindividual distance between coordinates of only 2.7 mm. Interindividual spatial variation in personalized targets exceeded intraindividual variation by a factor of up to 6.85, suggesting that personalized targets did not trivially converge to a group-average site. Moreover, personalized targets were heritable, suggesting that connectivity-guided rTMS personalization is stable over time and under genetic control. This computational framework provides capacity for personalized connectivity-guided TMS targets to be robustly computed with high precision and has the flexibly to advance research in other basic research and clinical applications.


Assuntos
Conectoma/normas , Transtorno Depressivo Resistente a Tratamento/terapia , Córtex Pré-Frontal Dorsolateral , Estimulação Magnética Transcraniana/normas , Adulto , Conectoma/métodos , Transtorno Depressivo Resistente a Tratamento/diagnóstico por imagem , Córtex Pré-Frontal Dorsolateral/diagnóstico por imagem , Estudos de Viabilidade , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Reprodutibilidade dos Testes , Estimulação Magnética Transcraniana/métodos , Adulto Jovem
19.
Mol Psychiatry ; 26(8): 4036-4045, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-31666679

RESUMO

Adults with childhood-onset attention-deficit hyperactivity disorder (ADHD) show altered whole-brain connectivity. However, the relationship between structural and functional brain abnormalities, the implications for the development of life-long debilitating symptoms, and the underlying mechanisms remain uncharted. We recruited a unique sample of 80 medication-naive adults with a clinical diagnosis of childhood-onset ADHD without psychiatric comorbidities, and 123 age-, sex-, and intelligence-matched healthy controls. Structural and functional connectivity matrices were derived from diffusion spectrum imaging and multi-echo resting-state functional MRI data. Hub, feeder, and local connections were defined using diffusion data. Individual-level measures of structural connectivity and structure-function coupling were used to contrast groups and link behavior to brain abnormalities. Computational modeling was used to test possible neural mechanisms underpinning observed group differences in the structure-function coupling. Structural connectivity did not significantly differ between groups but, relative to controls, ADHD showed a reduction in structure-function coupling in feeder connections linking hubs with peripheral regions. This abnormality involved connections linking fronto-parietal control systems with sensory networks. Crucially, lower structure-function coupling was associated with higher ADHD symptoms. Results from our computational model further suggest that the observed structure-function decoupling in ADHD is driven by heterogeneity in neural noise variability across brain regions. By highlighting a neural cause of a clinically meaningful breakdown in the structure-function relationship, our work provides novel information on the nature of chronic ADHD. The current results encourage future work assessing the genetic and neurobiological underpinnings of neural noise in ADHD, particularly in brain regions encompassed by fronto-parietal systems.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Adulto , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Humanos , Imageamento por Ressonância Magnética , Vias Neurais/diagnóstico por imagem
20.
Mol Psychiatry ; 26(7): 3512-3523, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-32963336

RESUMO

The heterogeneity of schizophrenia has defied efforts to derive reproducible and definitive anatomical maps of structural brain changes associated with the disorder. We aimed to map deviations from normative ranges of brain structure for individual patients and evaluate whether the loci of individual deviations recapitulated group-average brain maps of schizophrenia pathology. For each of 48 white matter tracts and 68 cortical regions, normative percentiles of variation in fractional anisotropy (FA) and cortical thickness (CT) were established using diffusion-weighted and structural MRI from healthy adults (n = 195). Individuals with schizophrenia (n = 322) were classified as either within the normative range for healthy individuals of the same age and sex (5-95% percentiles), infra-normal (<5% percentile) or supra-normal (>95% percentile). Repeating this classification for each tract and region yielded a deviation map for each individual. Compared to the healthy comparison group, the schizophrenia group showed widespread reductions in FA and CT, involving virtually all white matter tracts and cortical regions. Paradoxically, however, no more than 15-20% of patients deviated from the normative range for any single tract or region. Furthermore, 79% of patients showed infra-normal deviations for at least one locus (healthy individuals: 59 ± 2%, p < 0.001). Thus, while infra-normal deviations were common among patients, their anatomical loci were highly inconsistent between individuals. Higher polygenic risk for schizophrenia associated with a greater number of regions with infra-normal deviations in CT (r = -0.17, p = 0.006). We conclude that anatomical loci of schizophrenia-related changes are highly heterogeneous across individuals to the extent that group-consensus pathological maps are not representative of most individual patients. Normative modeling can aid in parsing schizophrenia heterogeneity and guiding personalized interventions.


Assuntos
Esquizofrenia , Substância Branca , Adulto , Anisotropia , Encéfalo/diagnóstico por imagem , Estudos Transversais , Humanos , Esquizofrenia/diagnóstico por imagem , Esquizofrenia/genética , Substância Branca/diagnóstico por imagem
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