Low-Frequency Intracortical Electrical Stimulation Decreases Sensorimotor Cortex Hyperexcitability in the Acute Phase of Ischemic Stroke

Ischemic stroke causes a series of complex pathophysiological events in the brain. Electrical stimulation of the brain has been considered as a novel neuroprotection intervention to save the penumbra. However, the effect on the cells' responsiveness and their ability to survive has yet to be established. The objective of the present study was to investigate the effects of low-frequency intracortical electrical stimulation (lf-ICES) applied to the ischemia-affected sensorimotor cortex immediately following ischemic stroke. Twenty male Sprague-Dawley rats were instrumented with an intracortical microelectrode array (IC MEA) and a cuff-electrode around the sciatic nerve. Photothrombosis intervention was performed within the sensorimotor cortex and the electrophysiological changes were assessed by analysis of the neural responses to stimulation of the sciatic nerve. Neuroprotection intervention consisted of eight 23 min lf-ICES blocks applied to the IC MEA during the initial 4 h following photothrombosis. Our results revealed that the area and magnitude of the sensorimotor cortex response significantly increased if ischemic stroke was allowed to progress uninterrupted, whereas this was not observed for the group of rats subjected to lf-ICES. Our findings indicate that low-frequency electrical stimulation is able to minimize hyperexcitability and may therefore be a candidate as neuroprotection intervention in the future.