Bushnell M C, Duncan G H, Dubner R, He L F
J Neurophysiol. 1984 Jul;52(1):170-87. doi: 10.1152/jn.1984.52.1.170.
We analyzed the activity of 51 trigeminothalamic neurons in the medullary dorsal horn (trigeminal nucleus caudalis) of monkeys during the performance of behavioral tasks requiring the monkeys to discriminate innocuous and noxious thermal stimuli applied to the face and to detect the onset of visual stimuli. Static properties of trigeminothalamic neurons in behaving monkeys were similar to those in anesthetized monkeys. Responses to passively presented mechanical and thermal stimuli, receptive-field properties, and conduction velocities did not differ in the awake and anesthetized states. For most wide dynamic range and nociceptive-specific trigeminothalamic neurons, there was a negative correlation between the magnitude of thermally evoked activity and behavioral latencies to discriminate 47 and 49 degrees C stimuli. Thus, both groups of neurons provide information that could be used by the monkey to discriminate noxious thermal stimuli. The magnitude of thermal responses of trigeminothalamic neurons was modulated by the behavioral significance of the stimulus. Behaviorally relevant thermal stimuli presented during the thermal discrimination task produced a greater neuronal response than equivalent irrelevant thermal stimuli presented between behavioral trials or presented while the monkey performed the visual detection task. Neurons whose activity is modulated by behavioral state are likely to be involved in discrimination of thermal stimuli, since the activity of these neurons correlates with the behavioral response to the stimuli and information from the modulated neurons is sent to the thalamus. Some trigeminothalamic neurons that exhibited somatosensory responses also responded to behaviorally relevant stimuli and events associated with trial initiation and receipt of reward in the behavioral tasks. Similar events outside a behavioral task evoked no neuronal responses. These task-related responses were similar to those described previously for medullary dorsal horn neurons not identified as to projection sites (14).(ABSTRACT TRUNCATED AT 400 WORDS)
我们分析了猴子延髓背角（三叉神经尾侧核）中51个三叉丘脑神经元在执行行为任务期间的活动，这些任务要求猴子辨别施加于面部的无害和有害热刺激，并检测视觉刺激的开始。行为猴子中三叉丘脑神经元的静态特性与麻醉猴子中的相似。在清醒和麻醉状态下，对被动呈现的机械和热刺激的反应、感受野特性以及传导速度并无差异。对于大多数广动态范围和伤害性特异的三叉丘脑神经元，热诱发活动的幅度与辨别47和49摄氏度刺激的行为潜伏期之间存在负相关。因此，这两组神经元都提供了猴子可用于辨别有害热刺激的信息。三叉丘脑神经元的热反应幅度受刺激的行为意义调节。在热辨别任务期间呈现的与行为相关的热刺激比在行为试验之间呈现的等效无关热刺激或猴子执行视觉检测任务时呈现的热刺激产生更大的神经元反应。其活动受行为状态调节的神经元可能参与热刺激的辨别，因为这些神经元的活动与对刺激的行为反应相关，并且来自被调节神经元的信息被发送到丘脑。一些表现出躯体感觉反应的三叉丘脑神经元也对与行为任务中的试验开始和奖励接收相关的行为相关刺激和事件做出反应。行为任务之外的类似事件未诱发神经元反应。这些与任务相关的反应与先前描述的未确定投射部位的延髓背角神经元的反应相似（14）。（摘要截短于400字）
