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White matter hyperintensity (WMH) is a common finding in aging population and considered to be a contributor to cognitive decline. Our study aimed to characterize the spatial patterns of WMH in different severities and explore its impact on cognition and brain microstructure in non-demented elderly. Lesions were both qualitatively (Fazekas scale) and quantitatively assessed among 321 community-dwelled individuals with MRI scanning. Voxel- and atlas-based analyses of the whole-brain white matter microstructure were performed. The WMH of the same severities was found to occur uniformly with a specific pattern of lesions. The severity of WMH had a significant negative association with the performance of working and episodic memory, beginning to appear in Fazekas 3 and 4. The white matter tracts presented significant impairments in Fazekas 3, which showed brain-wide changes above Fazekas 4. Lower FA in the superior cerebellar peduncle and left posterior thalamic radiation was mainly associated with episodic memory, and the middle cerebellar peduncle was significantly associated with working memory. These results support that memory is the primary domain to be affected by WMH, and the effect may potentially be influenced by tract-specific WM abnormalities. Fazekas scale 3 might be the critical stage predicting a future decline in cognition. [ABSTRACT FROM AUTHOR]

Patients with type 2 diabetes mellitus (T2DM) have a considerably high risk of developing dementia, especially for those with mild cognitive impairment (MCI). The investigation of the microstructural change of white matter (WM) between T2DM with amnesic MCI (T2DM-aMCI) and T2DM with normal cognition (T2DM-NC) and their relationships to cognitive performances can help to understand the brain variations in T2DM-related amnesic cognitive impairment. In the current study, 36 T2DM-aMCI patients, 40 T2DM-NC patients, and 40 healthy control (HC) individuals underwent diffusion tensor image and T1-weighted MRI scans and comprehensive cognition assessments. All of these cognitive functions exhibited intergroup ranking differences in patients. The T2DM-NC patients and HC individuals did not reveal any significant differences in WM integrity. The T2DM-aMCI patients showed disrupted integrity in multiple WM tracts compared with HC and T2DM-NC. Specifically, the damaged WM integrity of the right inferior fronto-occipital fasciculus and the right inferior longitudinal fasciculus exhibited significant correlations with episodic memory and attention function impairment in T2DM patients. Furthermore, cognitive impairment-related WM microstructural damage was associated with the degeneration of cortex connected to the affected WM tract. These findings indicate that degeneration exists extensively in WM tracts in T2DM-aMCI, whereas no brain WM damage is evident in T2DM-NC. [ABSTRACT FROM AUTHOR]

Response conflict can be induced by priming multiple responses competing for control of action in trials. The N2 is one functionally-related cognitive control index for response conflict. And yet the underlying whiter matter neural substrates of inter-individual difference in conflict N2 remain unclear. So the aim of present study was to address the white matter microstructure of the N2 responsible for conflict by directly relating the amplitude cost of the event-related potential (ERP) N2 component to diffusion tensor imaging (DTI) indices in healthy subjects. Thirty healthy subjects underwent DTI scanning and electrophysiology recording during a modified Flanker task. N2 was a stimulus-locked negative ERP component. Fractional anisotropy (FA) was calculated based on DTI measures and was assumed to reflect the integrity of myelinate fiber bundles. Therefore, we tested the relationship between N2 amplitude and FA in brain white matter. Results showed that FA, an index for white matter characteristics, in the right superior longitudinal fasciculus (SLF) was significantly positively associated with N2 amplitude cost. The N2 amplitude cost also predicted response time (RT) cost in the Flanker task. Higher FA was associated with larger N2 amplitude cost, suggesting that changes in white matter integrity in the SLF may account for changes in efficient transmission of fronto-parietal modulatory conflict signals. [ABSTRACT FROM AUTHOR]