The effects of selective septal lesions on theta production in CA1 and the dentate gyrus of the hippocampus

The effects of selective lesions of the lateral, medial or entire septum on theta production in CA1 and dentate were studied in the chronically implanted rat. It was found that lateral septal lesions disrupted theta production in the CA1 area of the hippocampus but did not affect dentate theta. Small medial septal lesions affected both CA1 and dentate theta. Total septal lesions abolished both CA1 and dentate theta. These results suggest that the pathways mediating the theta inputs to the CA1 and dentate generators are at one point anatomically distinct.