Miyazato H, Skinner R D, Reese N B, Mukawa J, Garcia-Rill E
Department of Neurosurgery, University of The Ryukyus, Okinawa, Japan.
Neuroscience. 1996 Nov;75(1):289-300. doi: 10.1016/0306-4522(96)00176-5.
The P13 midlatency auditory evoked potential in the rat is (i) sleep state dependent, (ii) undergoes rapid habituation and (iii) is blocked by the cholinergic antagonist scopolamine. As such, the P13 potential in the rat shows the same characteristics as the P1 (or P50) potential in the human. These potentials are thought to be mediated, at least in part, by the cholinergic arm of the reticular activating system. Previous studies have linked the reticular activating system with the startle response. The present study was undertaken to explore this relationship by simultaneously recording the P13 potential and the electromyographically recorded startle response using stimuli designed to elicit each response. Simultaneous recordings from the vertex and neck musculature following auditory click stimuli showed that: (i) the mean threshold of the P13 potential was 69.3 +/- 1.9 dB, while that for the startle response was 87.9 +/- 6.4 dB; (ii) the P13 potential was present during waking and paradoxical sleep, but absent during slow-wave sleep, while the startle response was present reliably only during waking; (iii) both responses habituated in response to paired stimuli, but the startle response was more habituated than the P13 potential; and (iv) both responses were facilitated by trains of stimuli in a similar manner. Recordings carried out from the auditory cortex verified that the primary cortical response had properties different from the P13 potential; i.e. it was present during all sleep-wake states, had a lower threshold and did not habituate rapidly. Finally, different patterns of startle responses were detected in the neck muscles. In every case, the P13 potential occurred during the middle, inhibitory phase of the startle response. These results suggest that the P13 potential and the startle response share response features, but the P13 potential appears to be more sensitive to auditory stimulation and to sleep-wake states. The startle response may be modulating descending systems by priming the spinal cord to respond in a "fight vs flight" fashion. On the other hand, the P13 response may be modulating ascending systems by triggering thalamocortical activity and resetting descending systems to allow novel motor strategies.
大鼠的P13中潜伏期听觉诱发电位具有以下特点：（i）依赖睡眠状态；（ii）会迅速产生习惯化；（iii）会被胆碱能拮抗剂东莨菪碱阻断。因此，大鼠的P13电位与人类的P1（或P50）电位具有相同的特征。这些电位被认为至少部分是由网状激活系统的胆碱能分支介导的。先前的研究已将网状激活系统与惊吓反应联系起来。本研究旨在通过使用旨在引发每种反应的刺激同时记录P13电位和肌电图记录的惊吓反应来探索这种关系。在听觉点击刺激后从头顶和颈部肌肉组织进行的同步记录显示：（i）P13电位的平均阈值为69.3±1.9dB，而惊吓反应的平均阈值为87.9±6.4dB；（ii）P13电位在清醒和异相睡眠期间出现，但在慢波睡眠期间不存在，而惊吓反应仅在清醒时可靠出现；（iii）两种反应在对配对刺激的反应中都会产生习惯化，但惊吓反应比P13电位更易产生习惯化；（iv）两种反应都以类似的方式受到刺激序列的促进。从听觉皮层进行的记录证实，初级皮层反应具有与P13电位不同的特性；即它在所有睡眠-觉醒状态下都存在，阈值较低且不会迅速产生习惯化。最后，在颈部肌肉中检测到不同模式的惊吓反应。在每种情况下，P13电位都出现在惊吓反应的中间抑制阶段。这些结果表明，P13电位和惊吓反应具有共同的反应特征，但P13电位似乎对听觉刺激和睡眠-觉醒状态更敏感。惊吓反应可能通过使脊髓做好以“战斗或逃跑”方式做出反应的准备来调节下行系统。另一方面，P13反应可能通过触发丘脑皮质活动并重置下行系统以允许新的运动策略来调节上行系统。
