ABSTRACT
BACKGROUND AND PURPOSE: Cognitive dysfunction is common in multiple sclerosis (MS). The dorsal anterior insula (dAI) is a key hub of the salience network (SN) orchestrating access to critical cognitive brain regions. The aim of this study was to assess whole-brain dAI intrinsic functional connectivity (iFC) using resting-state functional MRI (rs-fMRI) in people with MS and healthy controls (HC) and test the relationship between cognitive reserve (CR) and dAI iFC in people with MS. METHODS: We studied 28 people with relapsing-remitting MS and 28 HC. CR index was quantified by combining premorbid IQ, leisure activities, and education level. For whole-brain iFC analyses, the bilateral dAI were used as seeds. Individual subject correlation maps were entered into general linear models for group comparison and to analyze the effect of CR index on dAI iFC, controlling for multiple comparisons. The correlation between CR index and iFC was assessed using a linear regression model. RESULTS: rs-fMRI analyses revealed a negative relationship between CR index and iFC within the left dAI and a left occipital cluster in people with MS including regions of the cuneus, superior occipital gyrus, and parieto-occipital sulcus. The regression analysis showed that people with MS and a higher CR index had a statistically significantly reduced iFC within the left dAI and the cluster. CONCLUSIONS: CR is relevant to functional connectivity within one of the main nodes of the SN, the dAI, and occipital regions in MS. These results have implications for how CR may modulate the susceptibility to cognitive dysfunction in MS.
Subject(s)
Cerebral Cortex/physiopathology , Cognitive Reserve , Multiple Sclerosis, Relapsing-Remitting/physiopathology , Nerve Net/physiopathology , Rest/physiology , Adult , Cerebral Cortex/diagnostic imaging , Humans , Magnetic Resonance Imaging , Male , Multiple Sclerosis, Relapsing-Remitting/diagnostic imaging , Nerve Net/diagnostic imagingABSTRACT
BACKGROUND AND PURPOSE: The purpose of this study was to investigate differences in brain cortical thickness of systemic lupus erythematosus (SLE) patients with and without episodic memory impairment and healthy controls. METHODS: We studied 51 patients divided in 2 groups (SLE with episodic memory deficit, n = 17; SLE without episodic memory deficit, n = 34) by the Rey Auditory Verbal Learning Test and 34 healthy controls. Groups were paired based on sex, age, education, Mini-Mental State Examination score, and accumulation of disease burden. Cortical thickness from magnetic resonance imaging scans was determined using the FreeSurfer software package. RESULTS: SLE patients with episodic memory deficits presented reduced cortical thickness in the left supramarginal cortex and superior temporal gyrus when compared to the control group and in the right superior frontal, caudal, and rostral middle frontal and precentral gyri when compared to the SLE group without episodic memory impairment considering time since diagnosis of SLE as covaried. There were no significant differences in the cortical thickness between the SLE without episodic memory and control groups. CONCLUSIONS: Different memory-related cortical regions thinning were found in the episodic memory deficit group when individually compared to the groups of patients without memory impairment and healthy controls.
Subject(s)
Cerebral Cortex/diagnostic imaging , Cognitive Dysfunction/diagnostic imaging , Lupus Erythematosus, Systemic/complications , Memory Disorders/etiology , Adult , Cerebral Cortex/pathology , Cognitive Dysfunction/etiology , Cross-Sectional Studies , Humans , Magnetic Resonance Imaging , Memory, Episodic , Middle Aged , Young AdultABSTRACT
OBJETIVO: Investigar a relação entre a espessura cortical medida pela ressonância magnética em regiões frontais e o desempenho em instrumentos que avaliam funções executivas em pacientes com HIV positivo. MATERIAIS E MÉTODOS: Participaram deste estudo 22 pacientes HIV-positivos, com déficits em funções executivas, sob terapia antirretroviral, idades entre 45 e 65 anos e escolaridade entre 3 e 20 anos. Foi realizada ressonância magnética com sequências convencionais, T1 3D, processado pelo Freesurfer para verificar espessura cortical. Instrumentos de avaliação das funções executivas: Teste de Trilhas, Wisconsin, Hayling, Dígitos (WAIS-III), fluência verbal ortográfica e Stroop. Para análise da relação espessura versus cognição, utilizou-se coeficiente de correlação de Pearson. RESULTADOS: Correlações significativas foram encontradas entre escores de: Wisconsin e espessura das regiões pré-central e orbitofrontal lateral à direita e pré-central esquerda; Teste de Trilhas e espessura da área pré-central direita e cíngulo anterior caudal esquerdo; e Teste Hayling e espessura da área lateral orbitofrontal esquerda. CONCLUSÃO: As correlações existentes entre medidas de espessura cortical pela ressonância magnética e desempenho cognitivo sugerem que os déficits executivos em pacientes HIV-positivos relacionam-se a uma redução da espessura cortical das regiões frontais.
OBJECTIVE: To investigate the correlation between frontal regions cortical thickness measured by magnetic resonance imaging of HIV-positive patients and their performance on instruments for assessing executive functions. MATERIALS AND METHODS: The present study included 22 HIV-positive patients in the age range from 45 to 65, schooling ranging between three and 20 years, with executive functions deficit and undergoing antiretroviral therapy. Magnetic resonance imaging was performed with conventional T1-weighted, 3D sequences and the images were processed with the Freesurfer software to measure cortical thickness. The following instruments were utilized to evaluate the patients' executive functions: Trail Making, Wisconsin, Hayling, working memory (WAIS-III), verbal fluency and Stroop tests. The Pearson's correlation coefficient was utilized in the data statistical analysis. RESULTS: Significant correlations were found between: Wisconsin scores and the thickness of the right pre-central, lateral and left pre-central orbitofrontal regions; Trail Making scores and thickness of right pre-central and left anterior caudal cingulate areas; and Hayling Test scores and thickness of the left lateral orbitofrontal area. CONCLUSION: Correlations between cortical thickness measurements by magnetic resonance imaging and cognitive performance suggest that the executive function deficit in HIV-positive patients are related to a reduction in the thickness of the frontal cortex.