Figure 1.

The role of sensory stimulation during the acute phase of ischemic stroke. The cerebral blood flow threshold for neuronal activation increases with time elapsed after arterial occlusion. Therefore, early sensory stimulation is more likely to activate viable cortical areas than delayed stimulation, e.g. 3 h after stroke onset (blue box). Cortical activation increases the regional oxygen demand and might lead to supply–demand mismatch in case of insufficient collateral flow. Supply–demand mismatch transients may in turn trigger peri-infarct depolarizations that worsen stroke outcome (red box). Conversely, cortical activation induced by early stimulation leads to neurovascular coupling that enhances collateral flow through an efficient system of cerebral anastomoses. Enhanced collateral flow is the supposed mechanism that mediates reperfusion and improves clinical outcome in the concept of early sensory stimulation-induced neuroprotection (green box).