Mays L E, Morrisse D W
School of Optometry, University of Alabama at Birmingham 35294, USA.
J Am Optom Assoc. 1995 Jul;66(7):419-22.
Single-unit recordings of pontine omnipause neurons (OPN) in the monkey have shown that these neurons cease firing for saccades in all directions. OPNs are located in pontine nucleus raphe' interpositus and are known to inhibit a variety of target neurons, including saccadic burst neurons. Recently, a single-unit investigation of these same OPNs revealed that they pause for blinks as well as saccades. Electrical microstimulation of the OPN area has been shown to inhibit saccadic eye movements in all directions. The present study is designed to determine if OPN area microstimulation inhibits blinks as well as saccades.
Two rhesus monkeys were trained to track visual targets for a reward. Eye and lid position were measured using the electromagnetic search coil technique. The pontine OPN area was located using single-unit recording and microstimulation techniques. OPN stimulation was delivered just before and during the presentation of air puffs to elicit blinks.
OPN are microstimulation inhibited air puff-induced blinks as well as saccades. The threshold current for inhibiting blinks was generally slightly higher than for inhibiting saccades.
Although OPN area stimulation inhibits blinks as well as saccades, the mechanisms for inhibiting these behaviors appears to be different. OPNs are known to inhibit saccadic burst neurons, but there is no evidence that these neurons inhibit orbicularis oculi motoneurons which burst for blinks. Moreover, the temporal pattern of OPN activity makes it unlikely that they directly suppress blinks. The OPN region appears to be important for eye retraction during blinks and may be associated with other pontine areas which control blinks.
对猴子脑桥全暂停神经元（OPN）的单神经元记录表明，这些神经元在所有方向的扫视过程中都会停止放电。OPN位于脑桥中间缝际核，已知其能抑制多种靶神经元，包括扫视爆发神经元。最近，对这些相同OPN的单神经元研究表明，它们在眨眼以及扫视时都会暂停。对OPN区域进行电微刺激已被证明能抑制所有方向的眼球扫视运动。本研究旨在确定对OPN区域进行微刺激是否也能抑制眨眼和扫视。
训练两只恒河猴追踪视觉目标以获取奖励。使用电磁搜索线圈技术测量眼睛和眼睑位置。利用单神经元记录和微刺激技术定位脑桥OPN区域。在吹气诱发眨眼之前和期间进行OPN刺激。
对OPN进行微刺激可抑制吹气诱发的眨眼以及扫视。抑制眨眼的阈值电流通常略高于抑制扫视的阈值电流。
虽然对OPN区域进行刺激可抑制眨眼和扫视，但抑制这些行为的机制似乎有所不同。已知OPN能抑制扫视爆发神经元，但没有证据表明这些神经元能抑制因眨眼而爆发的眼轮匝肌运动神经元。此外，OPN活动的时间模式使其不太可能直接抑制眨眼。OPN区域似乎在眨眼时眼球后缩过程中很重要，并且可能与其他控制眨眼的脑桥区域有关。
