Diaschisis as Cerebello-Cortical Loop Dysfunction in Acute Ischemic Stroke: A Network Framework for Outcome Variability.

Clinical outcomes after acute ischemic stroke remain highly heterogeneous, even among patients with comparable lesion characteristics and successful reperfusion, challenging traditional lesion-based models. Increasing evidence suggests that stroke should be conceptualized as a disorder of distributed brain networks, yet the mechanisms linking focal ischemia to large-scale dysfunction remain incompletely understood. In this review, we propose that diaschisis constitutes a central physiological mechanism underlying this transition from focal injury to network-level impairment. Building on advances in functional imaging, connectomics, and cerebellar physiology, we propose that diaschisis may be conceptualized, at least in part, as a disruption of cerebello-cortical loop dynamics rather than solely a nonspecific remote effect. These closed, polysynaptic circuits linking cortex, cerebellum, and thalamus support the integration of motor and cognitive processes and are particularly vulnerable to perturbation. Focal ischemia may therefore induce a cascade of dysfunction that propagates across these loops, leading to widespread impairment despite limited structural damage. Within this framework, outcome variability emerges from the interaction of three key factors: lesion characteristics, brain reserve and network vulnerability, and the extent of diaschisis. We further highlight that functional suppression of cerebellar output, even in the absence of structural degeneration, may play a critical role in mediating network dysfunction. This circuit-based perspective provides a mechanistic explanation for inter-individual variability in stroke outcomes and shifts the focus from lesion localization to network dynamics. Understanding diaschisis as a potential manifestation of cerebello-cortical loop dysfunction opens new avenues for prognosis and therapeutic intervention, emphasizing the potential of targeting network-level restoration to improve recovery after stroke.