To investigate neuronal activity involved in responses to noxious stimuli in conscious monkeys, the animals were subjected to a task that required them to detect a small change in facial skin temperature or light (second temperature: T2, second light: V2) relative to an initial condition (T1 or V1), and to detect changes in V2 along with a heat task. Recordings were obtained from 57 neurons in the ventral premotor cortex (PMv) during the heat or light detection task. T1 neurons and T2 neurons showed increased activity only during T1 or T2, and T1/T2 neurons were activated by both T1 and T2 stimuli. T1/T2 neurons showed an increase in firing at higher T1 temperatures, whereas T1 neurons did not. About half of the non-light/heat-sensitive T1/T2 neurons showed increased firing at higher T2 temperatures, whereas T2 neurons showed no such increase. The heat responses of heat-sensitive PMv neurons were significantly suppressed when monkeys shifted their attention from heat to light. The present findings suggest that heat-sensitive PMv neurons may be involved in motor responses to noxious heat, whereas light/heat-PMv neurons may be involved in emotional and motivational aspects of pain and inappropriate motor responses to allow escape from noxious stimuli.

为了研究清醒猴子对有害刺激的反应所涉及的神经元活动，对动物进行了一项任务，要求它们检测面部皮肤温度或光照（第二温度：T2，第二光照：V2）相对于初始皮肤的微小变化。条件（T1或V1），并检测热任务中V2的变化。在热或光检测任务期间，从腹前运动皮层（PMv）中的57个神经元获得了记录。T1神经元和T2神经元仅在T1或T2期间显示增加的活动，并且T1 / T2神经元被T1和T2刺激激活。T1 / T2神经元在较高的T1温度下显示出放电增加，而T1神经元则没有。大约一半的非光敏/热敏T1 / T2神经元在较高的T2温度下显示出增加的放电，而T2神经元没有显示出这种增加。当猴子将注意力从热转移到光时，热敏感的PMv神经元的热反应被显着抑制。目前的发现表明，热敏感的PMv神经元可能参与对有害热的运动反应，而光/热PMv神经元可能参与疼痛和不适当的运动反应的情绪和动机方面，从而逃避了有害刺激。