去甲肾上腺素对猕猴额叶延缓辨别作业相关神经元活动的效应

为了研究去甲肾上腺素在大脑认知功能中的作用,在3只猕猴进行延缓辨别作业的同时,在额叶弓状沟上支内侧部的皮层区,记录了230个作业相关神经元的电活动。对其中159个神经元观察了微量电泳去甲肾上腺素、妥拉苏林或心得安的效应。这些神经元在作业各期的分布是:开始期11个,暗示期28个,延缓期66个,反应期54个。约2/3的神经元在作业中出现兴奋反应(放电增多),1/3为抑制反应(放电减少)。在延缓期出现抑制反应的神经元,绝大多数对去甲肾上腺素敏感。在电泳去甲肾上腺素时,神经元的自发放电减少,延缓期的抑制加深。电泳妥拉苏林或心得安则出现相反的效应,即自发放电增多,延缓期的抑制减弱或不出现抑制,并可拮抗电泳去甲肾上腺素的抑制效应。实验结果提示,在额叶弓状沟上支内侧皮层神经元的注意、短时记忆等认知功能中,可能有去甲肾上腺素参与作用,主要参与神经活动的抑制过程。

EFFECT OF NOREPINEPHRINE ON THE FRONTAL NEURON ACTIVITY RELATED TO DELAYED DISCRIMINATION TASK IN MONKEYS

To study the role of norepinephrine (NE) in the cognitive function of thebrain, the effects of NE, tolazoline (TOL) and propranolol (PR) on the activityof frontal neurons were examined in 3 rhesus monkeys (Macaca mulatta) duringthe performance of a delayed visual discrimination go/no-go task. Of the 230task-related neurons recorded from the area medial to the superior ramus of thearcuate sulcus, 159 neurons were tested with NE applied microiontophoretically.Of these tested neurons, 11 neurons were related to starting period, 28 neurons tocue period, 66 neurons to delay period and 54 neurons to response period. About2/3 of these neurons increased in discharge rate in the task, and the rest decreased.For most of the neurons with decrease of discharge rate in the delay period, thedischarge rate was further decreased during application of NE. During applicationof TOL or PR, the discharge rate was increased and the effect of NE was anta-gonized. The present results suggest that NE may play a role in the cognitive func-tion of the frontal neurons, particularly in attention and short-term memory, andmay be involved in the inhibitory process of the neuronal activities.