Formation of a conditioned "passive" avoidance reaction following ablation of the midbrain central gray]

Formation of conditioned "passive" avoidance reaction was studied in rats with a single pain reinforcement after electrolythic destruction of mesencephalic part of the central gray substance (CGS). The ablation of CGS ventral nuclei at the level of the midbrain rostral part led to a decrease in emotional reaction of "fears" and to disturbance of avoidance conditioning. The participation of midbrain limbic structures in learning and memory is discussed.