The Cerebellar Connectome Disruptions in Ischemic Stroke

TL;DR

This study shows that ischemic stroke disrupts the brain's functional connections, especially between the cerebellum and other brain regions, which could help explain post-stroke impairments.

Contribution

The study reveals novel patterns of cerebellar connectome disruptions in ischemic stroke patients and links them to stroke severity and lesion size.

Findings

Stroke patients showed increased intra-hemispheric and decreased inter-hemispheric cerebral connectivity.

Cerebellar inter-module connectivity increased, while connectivity between ipsilesional cerebral and cerebellar modules decreased.

Connectivity changes correlated with stroke severity and lesion size, suggesting a link to clinical outcomes.

Abstract

Supratentorial focal lesions following ischemic stroke can lead to crossed cerebellar diaschisis (CCD). However, it remains unclear how CCD affects the functional connectivity between the cerebellum and the rest of the brain in ischemic stroke patients.

This case–control study involved resting‐state fMRI data from 65 patients with basal ganglia ischemic stroke (Stroke) and 72 healthy controls (HC). Cerebral, cerebellar, and cerebrocerebellar inter‐module functional connectivity in both 7‐module and 17‐module conditions were calculated and compared between the Stroke and HC groups. Spearman correlation analyses were further conducted to examine the relationships between connectivity alterations and both stroke severity and lesion size in Stroke patients.

The Stroke patients exhibited disrupted inter‐module functional connectivity, characterized by increased intra‐hemispheric and decreased inter‐hemispheric connectivity between cerebral modules, increased inter‐module connectivity in the cerebellum, and reduced connectivity between ipsilesional cerebral modules and cerebellar modules while increasing connectivity between contralesional cerebral modules and cerebellar modules. Moreover, these connectivity changes, particularly disruptions in the cerebellar connectome, may be associated with lesion size and stroke severity in Stroke patients.

These findings highlight the importance of cerebellar connectome disruptions in ischemic stroke, which may provide valuable insights into the disease's underlying brain mechanisms.

Ischemic stroke disrupts the brain's modular organization (based on the Yeo/Buckner template). In patients with basal ganglia ischemic stroke, inter‐module functional connectivity is altered, characterized by increased intra‐cerebellar connectivity, reduced connectivity between ipsilesional cerebral and cerebellar modules, and enhanced connectivity between contralesional cerebral and cerebellar modules. Moreover, these cerebellar connectivity changes showed preliminary correlations with lesion size and clinical severity in exploratory analyses. These distinct network disruptions provide novel insights into post‐stroke deficits and potential targets for neuromodulation therapies.

Figures