We assessed the cerebral blood flow (CBF) response to electrical stimulation of the contralateral forearm over the primary somatosensory cortex (S-I) in anesthetized cats. CBF was monitored continuously using laser-Doppler flowmetry (LDF). In the first set of experiments, the effects of varying stimulus frequency and intensity were examined. During stimulation, CBF in S-I was increased significantly. At high stimulus intensity, response reached a near-plateau level. In the second set of experiments, the CBF response after introduction of an intracerebral mass was investigated using a mechanical microballoon model to simulate an intracerebral hematoma. A microballoon was inserted into the ventral posterolateral nucleus of the thalamus (VPL). Following gradual balloon inflation, there was a rapid reduction in CBF response. We conclude that CBF regulation to neuronal activation is affected by stimulation parameters, and is impaired by an intracerebral mass obstructing the afferent sensory pathway.