Following the completion of testing, rats were overdosed on isoflurane and transcardially perfused with 4% paraformaldehyde (PFA). The electrode assembly was removed from the skull and brains were extracted. Brains were postfixed for 48 h in 4% PFA before being moved to a 30% sucrose solution for cryoprotection. Following cryoprotection, brains were blocked, flash-frozen in alcohol, and sectioned on a freezing microtome. The 40-µm coronal sections were cut throughout the extent of the ACC and DMS. Sections were collected, mounted to positively charged Superfrost slides, and underwent Nissl staining. Slides were viewed under a light microscope, and the extent of the lesion and presence or absence of electrode tracks were verified and cross-referenced with score sheets demarcating electrode assembly advancement. Traces of the lesion and electrode tracks were placed on coordinate matched printouts of stereotaxic space.
