A Multimodal Structural and Functional Neuroimaging Study of Amnestic Mild Cognitive Impairment.

Examination of brain structural and functional abnormalities in amnestic mild cognitive impairment (aMCI) has the potential to enhance our understanding of the initial pathophysiological changes in dementia. We examined gray matter volumes and white matter microstructural integrity, as well as resting state functional connectivity (rsFC) in patients with aMCI (N = 48) in comparison to elderly cognitively healthy comparison subjects (N = 48). Brain volumetric comparisons were carried out using voxel-based morphometric analysis of T1-weighted images using the FMRIB Software Library. White matter microstructural integrity was examined using whole-brain tract-based spatial statistics analysis of fractional anisotropy maps generated from diffusion tensor imaging data. Finally, rsFC differences between the samples were examined by Multivariate Exploratory Linear Optimised Decomposition into Independent Components of the resting state functional magnetic resonance imaging time series, followed by between-group comparisons of selected networks using dual regression analysis. Patients with aMCI showed significant gray matter volumetric reductions in bilateral parahippocampal gyri as well as multiple other brain regions including frontal, temporal, and parietal cortices. Additionally, reduced rsFC in the anterior subdivision of the default mode network (DMN) and increased rsFC in the executive network were noted in the absence of demonstrable impairment of white matter microstructural integrity. We conclude that the demonstrable neuroimaging findings in aMCI include significant gray matter volumetric reductions in the fronto-temporo-parietal structures as well as resting state functional connectivity disturbances in DMN and executive network. These findings differentiate aMCI from healthy aging and could constitute the earliest demonstrable neuroimaging findings of incipient dementia.

Bharath S ，Joshi H ，John JP ，Balachandar R ，Sadanand S ，Saini J ，Kumar KJ ，Varghese M ... -  《-》

Differentiation of Early Alzheimer's Disease, Mild Cognitive Impairment, and Cognitively Healthy Elderly Samples Using Multimodal Neuroimaging Indices.

Joshi H ，Bharath S ，Balachandar R ，Sadanand S ，Vishwakarma HV ，Aiyappan S ，Saini J ，Kumar KJ ，John JP ，Varghese M ... -  《-》

Resting state functional connectivity abnormalities and delayed recall performance in patients with amnestic mild cognitive impairment.

Joshi H ，Bharath S ，John JP ，Sadanand S ，Saini J ，Kumar K ，Varghese M ... -  《-》

Altered functional connectivity in the default mode network is associated with cognitive impairment and brain anatomical changes in Parkinson's disease.

To assess whether functional neural connectivity is disrupted between the regions of the default mode network (DMN) in Parkinson's disease (PD) and how this connectivity is related to cognition, brain gray matter structure and white matter integrity and diffusivity. Thirty-seven PD patients and 16 healthy controls were evaluated, using resting-state functional magnetic resonance imaging (MRI), T1-weighted MRI, diffusion-weighted imaging and a battery of cognitive tests. Functional connectivity between the regions of the DMN, specifically in the precuneus, anterior and posterior cingulate, medial prefrontal and temporal and inferior parietal cortices was assessed with seed-to-voxel connectivity; gray matter volume and white matter values were determined using voxel-based morphometry and tract-based spatial statistics. Reduced functional connectivity was observed between the posterior cingulate and medial temporal lobe in PD. Lower cognitive performance, gray matter loss in posterior, medial temporal and parietal areas, and fractional anisotropy reduction in the white matter adjacent to DMN regions were also observed in PD patients compared with healthy controls. Lower DMN functional connectivity correlated with lower verbal and visual memory and visual abilities performance in PD. In addition, lower DMN functional connectivity correlated with lower gray matter volume in the posterior cingulate and precuneus, and with lower white matter fractional anisotropy of the inferior longitudinal and posterior cingulate fasciculi in PD. By combining different neuroimaging techniques and cognitive data, results showed that functional connectivity alteration between the regions of the DMN is associated with lower cognitive performance and gray and white matter abnormalities in PD.

Lucas-Jiménez O ，Ojeda N ，Peña J ，Díez-Cirarda M ，Cabrera-Zubizarreta A ，Gómez-Esteban JC ，Gómez-Beldarrain MÁ ，Ibarretxe-Bilbao N ... -  《-》

Diffuse alterations in grey and white matter associated with cognitive impairment in Shwachman-Diamond syndrome: evidence from a multimodal approach.

Perobelli S ，Alessandrini F ，Zoccatelli G ，Nicolis E ，Beltramello A ，Assael BM ，Cipolli M ... -  《NeuroImage-Clinical》