Basal Tegmental Self-Stimulation After Septal Ablation in Rats

Olds⁸ showed that stimulation of one of many areas of the brain could be used as a "reward" to maintain bar pressing and other behavior. Except for the amygdala, the areas most effective in sustaining high rates of responding were near the midline and extended continuously from the basal tegmentum through the hypothalamus and preoptic areas to the septum. The neurological basis for the "rewarding" effects elicited from these areas remains unknown. Several lines of evidence suggest that activity in some portion or portions of the rhinencephalon is involved in sustained self-stimulation behavior. MacLean and co-workers^6,7 have reported that septal or hippocampal stimulation may result in hippocampal seizure activity, which is followed by a period of electrical after-discharge. Behaviorally these animals show an immobilization phenomenon described as "catatonic-like" during the seizure itself, and "enhanced grooming" and "enhanced pleasure" reactions during the period of the after-discharge. That such a