An immunocytochemical method for marking microelectrode tracks following single-unit recordings in long surviving,...

We describe an immunocytochemical method for marking microelectrode tracks made during single-unit recordings in long surviving, awake monkeys. This procedure detects the increase in glial fibrillary acidic protein in the glial cells along a microelectrode track using commercially available antibodies. We have successfully marked electrode tracks in tissue from preparations having postrecording survival times ranging into months even though the gliosis can no longer be detected with conventional stains for cell bodies. When this method is combined with data from electrophysiological recordings in chronic preparations it will be possible to reconstruct functional architecture using chronic preparations, as has been done previously with acute preparations.