Activation of monkey locus coeruleus neurons varies with difficulty and performance in a target detection task.
Activation of monkey locus coeruleus neurons varies with difficulty and performance in a target detection task.
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猴子蓝斑神经元的激活随着目标检测任务的难度和表现而变化。
DOI：
10.1152/jn.00673.2003
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
Aston-Jones,Gary
中科院分区：
文献类型：
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作者：
Rajkowski,Janusz;Majczynski,Henryk;Clayton,Edwin;Aston-Jones,Gary
我们以前曾报道，在目标检测任务中，猴子蓝斑(LC)中的去甲肾上腺素能神经元被目标刺激选择性地激活。在这里，我们改变了这项任务的辨别难度，并记录了LC神经元的脉冲活动，以分析错误试验中的LC反应及其与行为反应时间(RTS)的关系。在易分辨和难分辨条件下，LC神经元对靶刺激的反应优先，呈时相激活。无论任务难度如何，这些反应总是先于行为反应。与容易辨别试验相比，困难试验的LC和行为反应潜伏期类似地增加。无论难度如何，快速RT试验的LC反应潜伏期也比慢速RT试验短，这表明LC和行为反应之间存在密切的时间关系。这种关系被LC活动的反应锁定直方图所证实，该直方图比刺激锁定直方图产生更多的时间同步LC反应。LC活性的总体直方图显示，导致错误警报反应的非靶标刺激产生阶段性LC激活(尽管比靶标命中试验要小)，而导致正确排斥反应的非靶标刺激对LC活性产生轻微的抑制。群体分析还显示，LC反应包括一个以前没有检测到的早期、小的兴奋成分。这种早期反应是非歧视的，因为靶向刺激试验和非靶向刺激试验是相似的。这些结果表明，LC神经元表现出与感觉刺激密切相关的早期小幅度反应。此外，这些细胞表现出较晚的、更大的反应，这种反应在时间上与行为反应有关。这些结果和其他结果引导我们假设LC反应是由决策过程驱动的，并有助于促进后续的行为反应。
We previously reported that noradrenergic neurons in the monkey locus coeruleus (LC) are activated selectively by target stimuli in a target detection task. Here, we varied the discrimination difficulty in this task and recorded impulse activity of LC neurons to analyze LC responses on error trials and in relation to behavioral response times (RTs). In easy and difficult discrimination conditions, LC neurons responded preferentially to target stimuli with phasic activation. These responses consistently preceded behavioral responses regardless of task difficulty. Latencies for LC and behavioral responses increased similarly for difficult compared with easy discrimination trials. LC response latencies were also shorter for fast RT trials compared with slow RT trials regardless of difficulty, indicating a close temporal relationship between LC and behavioral responses. This relationship was confirmed with response-locked histograms of LC activity, which yielded more temporally synchronized LC responses than stimulus-locked histograms. Population histograms of LC activity revealed that nontarget stimuli resulting in false alarm responses produced phasic LC activation (although smaller than for target-hit trials), and nontarget stimuli resulting in correct rejection responses yielded a small inhibition in LC activity. Population analyses also revealed that LC responses included an early, small excitatory component that was not previously detected. This early response was nondiscriminative because it was similar for target and nontarget stimulus trials. These results indicate that LC neurons exhibit early small magnitude responses that are closely linked to sensory stimuli. In addition, these cells show a later, larger magnitude response that is temporally linked to behavioral responses. These and other results lead us to hypothesize that LC responses are driven by decision processes and help facilitate subsequent behavioral responses.