JOAO RICARDO SATO
Projetos de Pesquisa
Unidades Organizacionais
LIM/44 - Laboratório de Ressonância Magnética em Neurorradiologia, Hospital das Clínicas, Faculdade de Medicina
5 resultados
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- Temporal Stability of Network Centrality in Control and Default Mode Networks: Specific Associations with Externalizing Psychopathology in Children and Adolescents(2015) SATO, Joao Ricardo; BIAZOLI JR., Claudinei Eduardo; SALUM, Giovanni Abrahao; GADELHA, Ary; CROSSLEY, Nicolas; SATTERTHWAITE, Theodore D.; VIEIRA, Gilson; ZUGMAN, Andre; PICON, Felipe Almeida; PAN, Pedro Mario; HOEXTER, Marcelo Queiroz; ANES, Mauricio; MOURA, Luciana Monteiro; DEL'AQUILLA, Marco Antonio Gomes; AMARO JR., Edson; MCGUIRE, Philip; LACERDA, Acioly L. T.; ROHDE, Luis Augusto; MIGUEL, Euripedes Constantino; JACKOWSKI, Andrea Parolin; BRESSAN, Rodrigo AffonsecaAbnormal connectivity patterns have frequently been reported as involved in pathological mental states. However, most studies focus on ""static,"" stationary patterns of connectivity, which may miss crucial biological information. Recent methodological advances have allowed the investigation of dynamic functional connectivity patterns that describe non-stationary properties of brain networks. Here, we introduce a novel graphical measure of dynamic connectivity, called time-varying eigenvector centrality (tv-EVC). In a sample 655 children and adolescents (7-15 years old) from the Brazilian ""High Risk Cohort Study for Psychiatric Disorders"" who were imaged using resting-state fMRI, we used this measure to investigate age effects in the temporal in control and default-mode networks (CN/DMN). Using support vector regression, we propose a network maturation index based on the temporal stability of tv-EVC. Moreover, we investigated whether the network maturation is associated with the overall presence of behavioral and emotional problems with the Child Behavior Checklist. As hypothesized, we found that the tv-EVC at each node of CN/DMN become more stable with increasing age (P < 0.001 for all nodes). In addition, the maturity index for this particular network is indeed associated with general psychopathology in children assessed by the total score of Child Behavior Checklist (P = 0.027). Moreover, immaturity of the network was mainly correlated with externalizing behavior dimensions. Taken together, these results suggest that changes in functional network dynamics during neurodevelopment may provide unique insights regarding pathophysiology. (C) 2015 Wiley Periodicals, Inc.
- Decreased centrality of subcortical regions during the transition to adolescence: A functional connectivity study(2015) SATO, Joao Ricardo; SALUM, Giovanni Abrahao; GADELHA, Ary; VIEIRA, Gilson; ZUGMAN, Andre; PICON, Felipe Almeida; PAN, Pedro Mario; HOEXTER, Marcelo Queiroz; ANES, Mauricio; MOURA, Luciana Monteiro; DEL'AQUILLA, Marco Antonio Gomes; CROSSLEY, Nicolas; AMARO JUNIOR, Edson; MCGUIRE, Philip; LACERDA, Acioly L. T.; ROHDE, Luis Augusto; MIGUEL, Euripedes Constantino; JACKOWSKI, Andrea Parolin; BRESSAN, Rodrigo AffonsecaInvestigations of brain maturation processes are a key step to understand the cognitive and emotional changes of adolescence. Although structural imaging findings have delineated clear brain developmental trajectories for typically developing individuals, less is known about the functional changes of this sensitive development period. Developmental changes, such as abstract thought, complex reasoning, and emotional and inhibitory control, have been associated with more prominent cortical control. The aim of this study is to assess brain networks connectivity changes in a large sample of 7- to 15-year-old subjects, testing the hypothesis that cortical regions will present an increasing relevance in commanding the global network. Functional magnetic resonance imaging (fMRI) data were collected in a sample of 447 typically developing children from a Brazilian community sample who were submitted to a resting state acquisition protocol. The fMRI data were used to build a functional weighted graph from which eigenvector centrality (EVC) was extracted. For each brain region (a node of the graph), the age-dependent effect on EVC was statistically tested and the developmental trajectories were estimated using polynomial functions. Our findings show that angular gyrus become more central during this maturation period, while the caudate; cerebellar tonsils, pyramis, thalamus; fusiform, parahippocampal and inferior semilunar lobe become less central. In conclusion, we report a novel finding of an increasing centrality of the angular gyrus during the transition to adolescence, with a decreasing centrality of many subcortical and cerebellar regions.
- Multimodal imaging of mild traumatic brain injury and persistent postconcussion syndrome(2015) DEAN, Philip J. A.; SATO, Joao R.; VIEIRA, Gilson; MCNAMARA, Adam; STERR, AnnetteBackground: Persistent postconcussion syndrome (PCS) occurs in around 5-10% of individuals after mild traumatic brain injury (mTBI), but research into the underlying biology of these ongoing symptoms is limited and inconsistent. One reason for this could be the heterogeneity inherent to mTBI, with individualized injury mechanisms and psychological factors. A multimodal imaging study may be able to characterize the injury better. Aim: To look at the relationship between functional (fMRI), structural (diffusion tensor imaging), and metabolic (magnetic resonance spectroscopy) data in the same participants in the long term (>1year) after injury. It was hypothesized that only those mTBI participants with persistent PCS would show functional changes, and that these changes would be related to reduced structural integrity and altered metabolite concentrations. Methods: Functional changes associated with persistent PCS after mTBI (>1year postinjury) were investigated in participants with and without PCS (both n=8) and non-head injured participants (n=9) during performance of working memory and attention/processing speed tasks. Correlation analyses were performed to look at the relationship between the functional data and structural and metabolic alterations in the same participants. Results: There were no behavioral differences between the groups, but participants with greater PCS symptoms exhibited greater activation in attention-related areas (anterior cingulate), along with reduced activation in temporal, default mode network, and working memory areas (left prefrontal) as cognitive load was increased from the easiest to the most difficult task. Functional changes in these areas correlated with reduced structural integrity in corpus callosum and anterior white matter, and reduced creatine concentration in right dorsolateral prefrontal cortex. Conclusion: These data suggest that the top-down attentional regulation and deactivation of task-irrelevant areas may be compensating for the reduction in working memory capacity and variation in white matter transmission caused by the structural and metabolic changes after injury. This may in turn be contributing to secondary PCS symptoms such as fatigue and headache. Further research is required using multimodal data to investigate the mechanisms of injury after mTBI, but also to aid individualized diagnosis and prognosis.
- Defining Multivariate Normative Rules for Healthy Aging using Neuroimaging and Machine Learning: An Application to Alzheimer's Disease(2015) OLIVEIRA, Ailton Andrade de; CARTHERY-GOULART, Maria Teresa; OLIVEIRA JUNIOR, Pedro Paulo de Magalhaes; CARRETTIERO, Daniel Carneiro; SATO, Joao RicardoBackground: Neuroimaging techniques combined with computational neuroanatomy have been playing a role in the investigation of healthy aging and Alzheimer's disease (AD). The definition of normative rules for brain features is a crucial step to establish typical and atypical aging trajectories. Objective: To introduce an unsupervised pattern recognition method; to define multivariate normative rules of neuroanatomical measures; and to propose a brain abnormality index. Methods: This study was based on a machine learning approach (one class classification or novelty detection) to neuroanatomical measures (brain regions, volume, and cortical thickness) extracted from the Alzheimer's Disease Neuroimaging Initiative (ADNI)'s database. We applied nu-One-Class Support Vector Machine (nu-OC-SVM) trained with data from healthy subjects to build an abnormality index, which was compared with subjects diagnosed with mild cognitive impairment and AD. Results: The method was able to classify AD subjects as outliers with an accuracy of 84.3% at a false alarm rate of 32.5%. The proposed brain abnormality index was found to be significantly associated with group diagnosis, clinical data, biomarkers, and future conversion to AD. Conclusion: These results suggest that one-class classification may be a promising approach to help in the detection of disease conditions. Our findings support a framework considering the continuum of brain abnormalities from healthy aging to AD, which is correlated with cognitive impairment and biomarkers measurements.
- Long-term structural changes after mTBI and their relation to post-concussion symptoms(2015) DEAN, Philip J. A.; SATO, Joao Ricardo; VIEIRA, Gilson; MCNAMARA, Adam; STERR, AnnettePrimary objective: To investigate sustained structural changes in the long-term (>1 year) after mild traumatic brain injury (mTBI) and their relationship to ongoing post-concussion syndrome (PCS). Research design: Morphological and structural connectivity magnetic resonance imaging (MRI) data were acquired from 16 participants with mTBI and nine participants without previous head injury. Main outcomes and results: Participants with mTBI had less prefrontal grey matter and lower fractional anisotropy (FA) in the anterior corona radiata and internal capsule. Furthermore, PCS severity was associated with less parietal lobe grey matter and lower FA in the corpus callosum. Conclusions: There is evidence for both white and grey matter damage in participants with mTBI over 1 year after injury. Furthermore, these structural changes are greater in those that report more PCS symptoms, suggesting a neurophysiological basis for these persistent symptoms.