RETICULOSPINAL NEURONS PARTICIPATING IN THE CONTROL OF SYNERGIC EYE AND HEAD MOVEMENTS DURING ORIENTING IN THE CAT .1. BEHAVIORAL PROPERTIES
RETICULOSPINAL NEURONS PARTICIPATING IN THE CONTROL OF SYNERGIC EYE AND HEAD MOVEMENTS DURING ORIENTING IN THE CAT .1. BEHAVIORAL PROPERTIES
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DOI：
10.1007/bf00243309
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发表时间：
1987-01-01
影响因子：
2
通讯作者：
BERTHOZ, A
中科院分区：
文献类型：
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作者：
GRANTYN, A;BERTHOZ, A
通过C1-C2水平的反向刺激，在清醒的头固定猫的脑桥轴突内记录了24个网状脊髓神经元（RSN）在自发注视转移和朝向新目标时的活动。分析神经元放电与眼球跳动、固定位置及颈背肌肌电图的关系。本报告描述了一组14个RSN在眼-头协同作用中表现出与运动参数相似类型的相关性的行为特性。这些“眼颈”RSN （EN-RSN）与同侧颈部肌电图的相相成分同步产生脉冲，并以可变的提前时间导致负向扫视。即使眼偏心位置保持不变并伴有持续的颈部肌肉活动，脉冲后也会有长时间的放电，其频率也会衰减。en - rsn的发射速率取决于眼睛的位置：当眼睛偏离对侧一半的动眼肌范围时，当同侧颈部肌肉放松时，en - rsn在其on方向上的扫视是沉默的。当眼睛穿过垂直经络时，与眼-头协同有关的相位和滋补成分的频率随着同侧眼位置的增加而成比例增加。14个en - rsn中的10个位于脑桥网状结构，接受来自对侧上丘的单突触输入。其中2个通过轴突内注射HRP标记，发现外展、面、内侧和外侧前庭核、前庭核和胼胝体间核以及尾侧脑桥和球网状结构中有广泛的分支。结论是，包括外展核前面的区域在内的尾侧桥状被盖含有rsn，其信号似乎适合于控制相颈肌肉活动，并投射到与眼部和面部运动相关的结构。与背前束的顶叶神经元的活动比较，揭示了在代表顶叶-网状-脊髓通路一级中继神经元的en - rsn水平上下降信号的深刻转变。
The activity of 24 reticulo-spinal neurons (RSN) identified by antidromic stimulation at the C1-C2 level has been recorded intra-axonally in the pons of alert head-fixed cats during spontaneous gaze shifts and orienting towards novel targets. Relationship of neuronal discharge to saccadic eye movements, positions of fixation and EMG of dorsal neck muscles were analysed. The present report describes behavioral properties of a group of 14 RSN showing similar types of correlations with motor parameters during eye-head synergies. These "eye-neck" RSN (EN-RSN) generate bursts in synchrony with phasic components of ipsilateral neck EMG and leading ipsiversive saccades by a variable lead time. Bursts are followed by a prolonged discharge whose frequency decays even when eccentric eye position is maintained constant and accompanied by sustained neck muscle activity. The firing rate of EN-RSNs depends on eye position: they are silent with saccades in their ON-direction when the eyes are deviated towards the contralateral half of the oculomotor range and the ipsilateral neck muscles are relaxed. When the eyes cross the vertical meridian, the frequency of phasic and tonic components related to eye-head synergies increase proportionally to ipsilateral eye position. Ten of the 14 EN-RSNs, located in the pontine reticular formation, received monosynaptic input from the contralateral superior colliculus. Two were labeled by intra-axonal injection of HRP which revealed extensive branching in the abducens, facial, medial and lateral vestibular, prepositus and intercalatus nuclei and in the caudal pontine and bulbar reticular formation. It is concluded that the caudal pontine tegmentum, including the region just anterior to the abducens nucleus, contains RSNs whose signals seem appropriate to control phasic neck muscle activity and which also project to structures related to ocular and facial movements. Comparisons with the perisaccadic activity of tectal neurons projecting in the predorsal bundle reveals a profound transformation of the descending signal at the level of EN-RSNs which represent first order relay neurons of the tecto-reticulo-spinal pathway.