Pure cortical ischemia versus striatal ischemia. Circulatory, metabolic, and neuropathologic consequences.

Selective ischemic damage was produced either involving only the cortex or together with the striatum by occlusion of the middle cerebral artery proximal or distal to the lenticulostriate artery in the rat. The consequences in local cerebral blood flow, local cerebral glucose utilization, and neuropathology were investigated in the acute stage of ischemia. Caudate damage produced by proximal occlusion resulted in such secondary alterations as enhanced blood flow and metabolism in areas remote from the main lesion, such as in the globus pallidus and substantia nigra ipsilateral to occlusion. After distal occlusion, however, there were two patterns distinctly different from each other in the appearance of the autoradiograms. One was ipsilateral and the other was contralateral enhancement of blood flow and metabolism involving the striato-pallido-nigral axis without any striatal damage. We therefore suggest that these secondary alterations in circulation and metabolism contribute to a varied neurological dysfunction after focal cerebral ischemia. Furthermore, our currently introduced model of selective ischemic lesioning is important in studying the roles of cortical and striatal influences in ischemic pathophysiology.