# Criticality and increased intrinsic neural timescales in stroke

## TL;DR

This study shows that stroke causes lasting changes in brain activity timing, which could help predict recovery and guide treatment.

## Contribution

The study introduces intrinsic neural timescales as potential biomarkers for stroke recovery and links them to criticality in brain dynamics.

## Key findings

- Stroke patients showed prolonged intrinsic neural timescales in multiple cortical regions.
- Dynamic changes in brain timing were more severe in patients with poor recovery outcomes.
- Computational models suggest stroke-induced changes reflect a shift toward criticality in brain dynamics.

## Abstract

Stroke disrupts brain function beyond focal lesions, altering multiscale temporal dynamics essential for information processing. We investigated intrinsic neural timescales (INT) and other properties of long-range temporal correlations, using longitudinal fMRI data from 15 ischemic stroke patients across 6 months, and compared them to age-matched controls. Results show that stroke patients exhibited significantly prolonged INT in multiple cortical regions, reflecting slowed temporal dynamics and disrupted hierarchy. These dynamic changes persisted through recovery and were more pronounced in patients with poor outcomes, especially within cognitive control networks. Computational modeling suggested that stroke-induced INT prolongation driven by heightened neuronal excitability reflects a dynamic shift towards criticality. Our findings position long-range temporal correlations and INT as potential biomarkers for monitoring and predicting functional recovery. This framework provides a novel perspective on stroke-induced brain changes and suggests avenues for targeted neurorehabilitation using interventions aiming at restoring intrinsic temporal dynamics.