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在猕猴执行随机延缓反应作业的同时,观察了微电泳多巴胺及其受体阻断剂氟哌啶醇对额叶作业相关神经元自发放电活动和诱发反应的影响。在该作业中,延缓期在1～4秒之间随机变化,在延缓期动物必须高度注意黄灯信号的出现,如稍不注意就会导致操作错误。在反应期,动物要在1秒钟内作出放开杠杆的反应。在实验中,对109个作业相关神经元观察了多巴胺的效应,这些神经元在作业间期共表现出神经元反应134个。神经元反应多出现在延缓期(48个)和反应期(72个),约占反应总数的90%。有近60%的神经元(61/109)对多巴胺敏感,多巴胺对神经元的自发放电活动既有兴奋效应(21/61),又有抑制效应(40/61),但以抑制效应为主。在延缓期出现反应的神经元中有31个(31/48)对多巴胺敏感,多巴胺对神经元的诱发反应主要起抑制作用(23/31);在反应期出现反应的神经元中有44个(44/72)对多巴胺敏感,多巴胺也以抑制作用为主(32/44),即使神经元的放电活动减弱。对54个(54/61)多巴胺敏感神经元观察了氟哌啶醇的效应,氟哌啶醇的效应与多巴胺相反,并能阻断多巴胺的效应。形态学检查表明,多巴胺敏感性神经元主要分布在大脑额叶弓状沟上支的内侧部。本实验表明,在延缓期和反应期出现放电变化的额叶神经元半数以上都对多巴胺敏感,且以抑制效应为主。由于作业的这两个时期分别与注意和视觉指导下的运动有关,因此,在视-运动耦合以及注意等过程中,在大脑额叶有多巴胺敏感神经元参与,而且主要是参与神经元活动的抑制过程。
In this study, we investigated the effects of micro-electrophoresis of dopamine and its receptor antagonist haloperidol on spontaneous firing activities and induced responses in frontal lobe-exposed neurons. In this operation, the delay period varies randomly between 1 and 4 seconds. During the delay period, the animal must pay close attention to the appearance of the yellow light signal. If it is ignored, the operation error will be caused. During the reaction period, the animal takes a one-second reaction to release the lever. In experiments, dopamine effects were observed on 109 home-working neurons that showed a total of 134 neuronal responses during the intervening period. Neuronal reaction occurred in the delay period (48) and the reaction period (72), accounting for about 90% of the total reaction. Nearly 60% of neurons (61/109) are sensitive to dopamine. Both dopamine and dopamine have both excitatory effects (21/61) and inhibitory effects (40/61) on the spontaneous firing activities of neurons, but mainly inhibitory effects . Thirty-one (31/48) of the neurons that reacted during the delay period were sensitive to dopamine, while dopamine predominantly inhibited the neuronal response (23/31). Of the neurons that reacted during the reaction period, 44 (44/72) were sensitive to dopamine, and dopamine was also predominantly inhibited (32/44), even though the neuronal discharge activity was weakened. Haloperidol effects were observed in 54 (54/61) dopamine-sensitive neurons. Haloperidol reversed the effect of dopamine and blocked the effects of dopamine. Morphological examination showed that dopamine-sensitive neurons mainly distributed in the medial part of the superior branch of the frontal lobe arcuate groove. This experiment showed that more than half of the frontal lobe neurons with discharge changes during the delay and reaction periods were sensitive to dopamine, and the predominant effect was inhibition. Because the two periods of operation are related to the attention and the movement under visual guidance respectively, dopamine-sensitive neurons are involved in the frontal lobe of the brain in the process of optic-motor coupling and attention, and are mainly involved in the activities of neurons Inhibit the process.