Electrophysiological transcortical diaschisis after middle cerebral arteryocclusion (MCAO) in rats

Remote changes in brain function following stroke are called diaschisis. Th ese remote effects may contribute to the neurological deficit following bra in infarction; in addition they may lead to post-stroke epilepsy and affect functional recovery. In the present study we addressed the question of whe ther an increase in excitability can be observed contralateral to middle ce rebral artery (MCA) infarction. Permanent occlusion of the middle cerebral artery (MCAO) was induced experimentally in rats with an intraluminal silic on-coated filament. Seven days later, brain excitability was tested with ex tracellulare recording techniques in neocortical coronal brain slices using a paired-pulse stimulus protocol. In rats with MCAO, excitability was incr eased in the neocortex contralateral to the infarction compared with the co ntrol group. These alterations extended through wide parts of the contralat eral neocortex. The study demonstrates that MCAO causes transcallosal elect rophysiological diaschisis. Together with results obtained previously with photothrombotic cortical lesions, it can be concluded that these remote eff ects are not due to characteristics of the individual lesion model, but are common consequences of brain lesions. (C) 1999 Published by Elsevier Scien ce Ireland Ltd. All rights reserved.