CHARACTERISTICS OF BEHAVIOR AND NEURONAL-ACTIVITY DURING OPERANT REWARD LEARNING AND FEEDING IN RABBITS WITH INSULIN DEFICIENCY

Behavioural changes during operant learning and feeding were studied in rabbits with insulin deficiency (ID) in chronic ditizone diabetes. Unit activity in the motor and sensorimotor cortex of freely moving rabbits was also studied during the operant behaviour. It was shown that the rabbits with ID displayed much more searching behaviour during learning than the intact ones, although the mean evaluations of the other types of behaviour (grooming, resting, alertness etc.) did not differ significantly. Acceleration of reward learning in the rabbits with ID was also observed. After injection of insulin (2-4 units) an hour before the operant feeding test an extreme reduction of searching behaviour was observed in the rabbits with ID in comparison with the control values as well as an enhancement of grooming, resting and other types of behaviour. Nevertheless, the amount of the operant feeding in this case did not change. Almost a half of neurons (46%) recorded in rabbits with ID manifested prolong activation correlated with the reward and/or food consuming. This proportion of <<feeding>> neurons in rabbits with ID was much higher than that in control ones (12%). The presented data indicate a significant transformation of behavioural and neuronal patterns in diabetic rabbits during operant reward learning and feeding and allow to consider the enhanced food motivation under ID as the main factor of learning acceleration.