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Open-field behaviour and emotionally differently reinforced learning were studied in male Wistar rats with bilaterally ablated Locus coeruleus. Histochemical analysis of the hypothalamic structures was carried out. Decrease of investigating activity and attention was found as well as disturbances of learning with emotionally-negative (painful) reinforcement. By means of histochemical methods, fluorescence characteristic for catecholamines was found to decrease sharply in paraventricular and supraoptic hypothalamic nuclei, eminentia medialis and the posterior lobe of the hypophysis.

A study was made on 79 Wistar male rats of the influence of destruction of single nuclei in the brain serotonin- and noradrenergic systems on their learning with alimentary and pain reinforcements. Electrolytic lesion of the raphe dorsal and medial nuclei hindered the formation of alimentary conditioned reflexes, while facilitating the elaboration of a conditioned active avoidance reaction. Destruction of the locus coeruleus was attended with improved alimentary learning, while the elaboration of conditioned active avoidance reaction proved to be more difficult as compared with that in the control animals. A conclusion is drawn that the nature of the influence of local ablation of individual nuclei in the brain serotonin- and noradrenergic systems on animals' learning is determined by the emotional sign of the reinforcing stimulus.