Bilateral cerebral hemodynamic response during unilateral direct electrical stimulation in the mouse somatosensory cortex

Abstract

We examined the effects of direct cortical electrical stimulation on the perfusion and the oximetry signals in the whole mouse cortex. An intrinsic optical imaging technique was used to assess the effects of stimulation on cerebral hemodynamics and lateralization. In anesthetized mouse, electrical stimulations with frequencies ranging from 50 to 250 Hz cause bilateral changes in cerebral blood flow and hemoglobin oxygenation signals. In the ipsilateral hemisphere, direct electrical stimulation brings about immediate increases in deoxy-hemoglobin concentration and cerebral blood flow. In the contralateral hemisphere, the stimulation also causes immediate weak increases in the deoxy-hemoglobin concentration and immediate intense increases in the blood flow. Overall, the unilateral direct cortical stimulation elicits significant hemodynamic changes in both the ipsi- and the contralateral sides in the somatosensory cortex of mice and these responses exhibit a frequency dependence. Our data show bilateral hemodynamic changes in the response to electrical stimulation and suggest the likely existence of brain lateralization of neurovascular coupling in the mouse somatosensory cortex.