Deep Cerebellar Low-Intensity Focused Ultrasound Stimulation Restores Interhemispheric Balance after Ischemic Stroke in Mice

Abstract

Ischemic damage after stroke disrupts the complex balance of inhibitory and excitatory activity within cortical network causing brain functional asymmetry. Cerebellar deep nuclei with its extensive projections to cortical regions could be a prospective target for stimulation to restore inter-hemispheric balance and enhance neural plasticity after stroke. In our study, we repeatedly stimulated the lateral cerebellar nucleus (LCN) by low-intensity focused ultrasound (LIFU) for 3 days to enhance rehabilitation after middle cerebral artery occlusion (MCAO) in a mouse stroke model. The neural activity of the mice sensorimotor cortex was measured using epidural electrodes and analyzed with quantified electroencephalography (qEEG). Pairwise derived Brain Symmetry Index (pdBSI) and delta power were used to assess the neurorehabilitative effect of LIFU stimulation. Compared to the Stroke (non-treated) group, the LIFU group exhibited a decrease in cortical pathological delta activity, significant recovery in pdBSI and enhanced performance on the balance beam walking test. These results suggest that cerebellar LIFU stimulation could be a non-invasive method for stroke rehabilitation through the restoration of interhemispheric balance.