Electrophysiological changes in the surrounding brain tissue of photochemically induced cortical infarcts in the rat.

Small infarctions in the parietal cortex of Wistar rats were produced photochemically using the Rose Bengal technique. The infarctions evoked reproducible cortical lesions of about 2 mm diameter. In the surrounding brain tissue changes in electrophysiological responses occurred. Whereas in control animals a paired-pulse inhibition could be evoked all over the neocortex, in infarcted animals the paired-pulse inhibition was significantly reduced or even absent within an area extending up to 5 mm lateral from the lesion center. The changes in paired-pulse inhibition were already present on the first day and persisted at least up to 60 days after infarction. These functional changes may contribute to neurological deficits occurring after cerebral infarcts.