Bindu P N, Desiraju T
Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bangalore.
Indian J Physiol Pharmacol. 1988 Oct-Dec;32(4):231-51.
In conscious Wistar rats neuromuscularly paralysed by gallamine, operantly conditioned reduction of heart rate was achieved under both negative and positive reinforcement schedules using the tail shock avoidance or the rewarding brain-stimulations in 20-min test sessions. The primary aim was to assess whether it would be possible to achieve operant conditioning of the heart rate, evoked not as a secondary reflex response of any voluntary skeletal muscular contractions of trunk but as a conditioned voluntary function of the central autonomic regulation of a visceral organ, since this entire subject was peculiarly left in confusion by Miller (5, 8) who wanted that others should independently study it. This study revealed interestingly that not every subject might be able to achieve the visceral learning in a given set of conditions, and suggested that this type of a special learning might be dependent on individual predisposition in the central nervous system. In the present study, 15 showed the learning, out of the 58 subjects assessed. It was also observed that there was a variation in the magnitude of the learning response among different learners, and, also, in the same subject in different sessions conducted on different days. This is considered as an indication that this type of conditioned autonomic function is probably not easily recruited into the long-term memory mechanisms. The overall average of the operant lowering of the heart rate progressively achieved by the end part of the learning session was about 10.5% from the basal average rate, and the score of reinforcement (per cent of painful tail shocks avoided, or of increase in number of brain shocks achieved) was over 80%. The extinction test confirmed the learning. Control experiments revealed that the conditioned heart rate changes were not due to any unconditioned stimulus effects. The learning observed under the brain-stimulation reinforcement was confirmed by losing the learning response after lesioning the site of the rewarding stimulation. The visceral operant learning occurring in state of somatomotor paralysis under both negative and positive types of reinforcement was blocked by haloperidol. Morphine delayed the onset of the pain avoidance operant learning, whereas it speeded up the hedonic brain-stimulation operant learning. The results, considered from all the above angles, dispell the doubt previously expressed about the occurrence of the operant conditioning of heart rate under a visceral learning paradigm.
在由加拉明导致神经肌肉麻痹的清醒Wistar大鼠中，在20分钟的测试时段内，通过尾部电击回避或奖励性脑刺激，在负强化和正强化程序下均实现了操作性条件反射性心率降低。主要目的是评估是否有可能实现心率的操作性条件反射，这种反射不是作为躯干任何随意骨骼肌收缩的次级反射反应而诱发，而是作为内脏器官中枢自主调节的条件性随意功能而诱发，因为米勒（5, 8）对整个这个主题特别感到困惑，他希望其他人能独立研究它。这项研究有趣地揭示，并非每个受试者在给定的一组条件下都能实现内脏学习，并表明这种特殊类型的学习可能取决于中枢神经系统中的个体易感性。在本研究中，在评估的58个受试者中，有15个表现出了学习能力。还观察到，不同学习者之间以及同一受试者在不同日期进行的不同时段中，学习反应的幅度存在差异。这被认为表明这种类型的条件性自主功能可能不容易被纳入长期记忆机制。在学习时段结束时逐渐实现的心率操作性降低的总体平均值相对于基础平均心率约为10.5%，强化得分（避免的痛苦尾部电击百分比或获得的脑电击次数增加百分比）超过80%。消退测试证实了学习。对照实验表明，条件性心率变化不是由于任何非条件刺激效应。在奖励性刺激部位损伤后失去学习反应，证实了在脑刺激强化下观察到的学习。氟哌啶醇阻断了在负强化和正强化两种类型下，躯体运动麻痹状态下发生的内脏操作性学习。吗啡延迟了疼痛回避操作性学习的开始，而加速了享乐性脑刺激操作性学习。从上述所有角度考虑，这些结果消除了先前对在内脏学习范式下心率操作性条件反射发生的怀疑。
