Conditioned responses of monkey locus coeruleus neurons anticipate acquisition of discriminative behavior in a vigilance task
Conditioned responses of monkey locus coeruleus neurons anticipate acquisition of discriminative behavior in a vigilance task
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DOI：
10.1016/s0306-4522(97)00060-2
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发表时间：
1997-10-01
期刊：
影响因子：
3.3
通讯作者：
Kubiak, P
中科院分区：
文献类型：
--
作者：
AstonJones, G;Rajkowski, J;Kubiak, P
实验记录了三只食蟹猴执行视觉辨别（警觉）任务时蓝斑核去肾上腺素能神经元的细胞外冲动活动。对于果汁奖励，受试者被要求对一个不可能的目标刺激（20%的试验）迅速释放一个杠杆，这个目标刺激随机混合在视频显示器上的非目标刺激中。在本实验中，所有蓝斑神经元均被目标刺激选择性地激活。其他任务事件（果汁奖励、杠杆释放、固定点刺激、非目标刺激）没有引起这些神经元的一致反应。随着任务偶然性的逆转，蓝斑神经元停止对前目标刺激的反应，并开始对新目标（旧的非目标）刺激作出反应。此外，逆转后蓝斑对目标刺激的反应潜伏期增加（约140 ms），同时行为反应潜伏期也有类似的增加。这些结果表明，条件蓝斑反应反映了刺激意义和认知加工，而不是由物理感觉属性驱动的。值得注意的是，任务逆转后蓝斑对刺激反应的逆转发生迅速，在数百次试验之前，逆转在行为反应中表现出来。这些结果表明，蓝斑神经元的条件反应具有可塑性，容易因刺激意义的改变而改变，蓝斑可能在学习行为重要刺激的意义方面发挥积极作用。(c) 1997年。Elsevier Science Ltd.出版。
Impulse activity was recorded extracellularly from noradrenergic neurons in the nucleus locus coeruleus of three cynomolgus monkeys performing a visual discrimination (vigilance) task. For juice reward, the subjects were required to release a lever rapidly in response to an improbable target stimulus (20% of trials) that was randomly intermixed with non-target stimuli presented on a video display. All locus coeruleus neurons examined were phasically and selectively activated by target stimuli in this task. Other task events elicited no consistent response from these neurons (juice reward, lever release, fix spot stimuli, non-target stimuli). With reversal of the task contingency, locus coeruleus neurons ceased responding to the former target stimuli, and began responding instead to the new target (old non-target) stimuli. In addition, the latency of locus coeruleus response to target stimuli increased after reversal (by about 140 ms) in parallel with a similar increase in the latency of the behavioral response. These results indicate that the conditioned locus coeruleus responses reflect stimulus meaning and cognitive processing, and are not driven by physical sensory attributes. Notably, the reversal in locus coeruleus response to stimuli after task reversal occurred rapidly, hundreds of trials before reversal was expressed in behavioral responses.These findings indicate that conditioned responses of locus coeruleus neurons are plastic and easily altered by changes in stimulus meaning, and that the locus coeruleus may play an active role in learning the significance of behaviorally important stimuli. (C) 1997 IBRO. Published by Elsevier Science Ltd.