Abnormal Local Brain Activity in SCA3 Patients with Cognitive Impairment: A Resting-State Functional MRI Study

Cerebellar Alteration in Resting-State Functional Connectivity Among Kratom (Mitragyna speciosa) Users: Insights from Functional MRI.

Prefrontal Neurovascular Coupling Abnormalities Associated With Cognitive Performance in Multiple Sclerosis

ABSTRACT Background Cognitive impairment is a prevalent and debilitating feature in multiple sclerosis (MS), yet its pathophysiology remains incompletely understood. Dysfunction of the neurovascular unit (NVU) and impaired neurovascular coupling (NVC) may be related to cognitive performance in MS, but this pathway remains insufficiently studied. This study investigated whether NVC abnormalities are associated with cognitive performance in MS. Methods Ninety‐seven MS patients and 83 healthy controls (HCs) underwent resting‐state functional magnetic resonance imaging (rs‐fMRI) and arterial spin labeling (ASL) perfusion MRI acquisition. The amplitude of low‐frequency fluctuations (ALFF) was used as an index of regional spontaneous neuronal activity, and cerebral blood flow (CBF) was quantified. NVC was quantified globally (CBF‐ALFF correlation) and regionally (CBF/ALFF ratio). We analyzed the correlations between regional NVC metrics and cognitive performance and Expanded Disability Status Scale (EDSS) scores. Sensitivity analyses tested robustness across alternative functional metrics, gray matter volume (GMV), T2 lesion volume, disability severity, treatment status, and the relapsing‐remitting multiple sclerosis (RRMS) subgroup. Results Compared with HCs, MS patients demonstrated (1) reduced CBF‐ALFF coupling in the ALFF‐based analysis, and (2) increased CBF/ALFF ratios in the bilateral medial prefrontal cortex (mPFC). The regional mPFC finding, particularly on the left, remained robust across sensitivity analyses and was associated with worse cognitive performance and higher EDSS scores. Conclusion These findings suggest altered NVC in MS, with regional prefrontal abnormalities representing the most robust and clinically relevant finding. Regional prefrontal NVC abnormalities may provide a potential imaging correlate of cognitive performance in MS.

Spatial correspondence between altered brain function and normative neurotransmitter density maps in Type 1 diabetes mellitus.

Abnormal coordination of executive control network and default mode network in cognitive impairment after deep nuclei intracerebral hemorrhage

This study investigated the macroscopic neural mechanisms of cognitive impairment after Deep Nuclei Intracerebral Hemorrhage (DNICH) from the dimensions of brain activity and brain networks, and further identified characteristic fingerprints of cognitive representation. Patients with cognitive impairment after DNICH and healthy controls (HC) were prospectively and consecutively enrolled. Resting-state fMRI (rs-fMRI) data and the cognitive scale Mini-Mental State Examination (MMSE) were collected. Spontaneous brain activity measured by fractional Amplitude of Low-Frequency Fluctuations (fALFF) was used to identify hub brain regions of cognitive representation, which were then used as Regions of Interest (ROI) for Functional Connectivity (FC) analysis, in order to investigate the potential mechanisms after DNICH cognitive impairment and identify characteristic fingerprints for distinguishing patients with dementia (dementia was defined as MMSE ≤ 17). This study enrolled 139 patients with DNICH and 100 HC. There were no significant differences in baseline characteristics including age, gender, years of education, height, and weight between the two groups. Hematomas were predominantly located in the bilateral basal ganglia, more commonly on the left side, with varying degrees of thalamic and white matter involvement. Whole-brain zfALFF analysis showed that MMSE scores were significantly correlated with zfALFF values in brain regions including right dorsolateral prefrontal cortex (R-DLPFC) and posterior cingulate cortex (PCC), with R-DLPFC positively correlated and PCC negatively correlated with cognition (AlphaSim correction, p < 0.01; cluster size >19). In addition, FC within the executive control network (ECN) and default mode network (DMN) was abnormally altered in patients with cognitive impairment and was closely associated with cognitive function ( r = −0.29–0.51). FC fingerprints demonstrated stable predictive ability for dementia status (AUC = 0.70–0.73). Abnormal coordination of intra-network and inter-network FC of ECN and DMN may represent a shared neural mechanism of cognitive impairment after DNICH. Modulating FC between these hub brain regions (R-DLPFC and PCC) may provide new therapeutic strategies for cognitive recovery after DNICH.

Substantia nigra iron-related alterations, white matter disruption, and functional network dysconnectivity in temporal lobe epilepsy: a multimodal neuroimaging study

The authors' multimodal findings suggest subregion- and laterality-specific alterations in the SN of patients with TLE, with patterns differing between RTLE and LTLE.

Reduced amplitude of low frequency fluctuation in the sensorimotor cortex in early psychosis: association with motor dexterity and hyperconnectivity

Previous studies have demonstrated widespread regional abnormalities in blood oxygen level-dependent (BOLD) amplitude of low frequency fluctuation (ALFF) in psychotic disorders. How regional ALFF is related to functional connectivity and behavior in psychotic illness, however, is poorly understood. Here we examined voxelwise ALFF across the brains of subjects with early psychosis (EP) vs. healthy controls (HCs) as well as its relationships to functional connectivity and task performance. Resting state fMRI data from 55 HCs and 109 participants with EP from the Human Connectome Project—Early Psychosis were analyzed. Our analytic strategy was to examine ALFF across the whole brain to determine what regions showed significant differences in the psychosis group and then determine how those regional abnormalities in ALFF were related to connectivity patterns with other brain areas. We then examined correlations between these measures and performance on task-relevant to the observed circuitry. Significantly lower ALFF was observed in the sensorimotor cortex in participants with EP vs. HC. Decreased sensorimotor ALFF in EP, furthermore, was associated with poor motor dexterity and cognitive function. Finally, in participants with EP, ALFF showed increased connectivity with the cerebellum, anterior cingulate, and insula. Our results suggest that spontaneous low-frequency blood oxygen level-dependent fluctuation amplitude is significantly lower in sensorimotor cortex in EP, and that this change is associated with poor motor skills and cognition. Hyperconnectivity within the observed circuits in participants with EP may indicate more widespread pathology with areas that show abnormally low levels of baseline BOLD fluctuation.