Effects of sensory stimuli on single cell activity in the septum of the cat

Abstract

Single cell activity was studied in the diagonal band of Broca and the medial septal nucleus in cats. The average rate of the spontaneous firing was higher in the diagonal band and showed more burst activity than in the medial nucleus. Photic, sciatic, and acoustic stimulation significantly changed the rate of firing of most of the septal units with about equal numbers showing facilitation and inhibition. Statistical analysis has demonstrated that the average spontaneous activity of the facilitatory units was lower than that of the inhibitory cells for each of the three sensory modalities. The septal units have demonstrated a very high degree of sensory convergence on the same cell. Chloralose anesthesia decreased the spontaneous activity and the degree of sensory responsiveness of the septal units. The possible afferent pathways affecting septal unit activity and its significance are discussed.