NEURAL CONTROL OF VERGENCE EYE-MOVEMENTS - CONVERGENCE AND DIVERGENCE NEURONS IN MIDBRAIN
NEURAL CONTROL OF VERGENCE EYE-MOVEMENTS - CONVERGENCE AND DIVERGENCE NEURONS IN MIDBRAIN
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DOI：
10.1152/jn.1984.51.5.1091
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发表时间：
1984-01-01
影响因子：
2.5
通讯作者：
MAYS, LE
中科院分区：
文献类型：
--
作者：
MAYS, LE
具有双眼单视能力的动物使用分离（聚散）眼球运动来将两只眼睛对准视觉目标。多项证据表明，共轭和聚散眼动命令是独立生成的，并在医学直肌运动神经元处组合。可能存在纯聚散度眼睛位置信号，该信号与眼睛之间的水平角（聚散角）成正比，而不考虑共轭凝视的方向。研究了携带纯聚散信号的神经元。细胞外单位记录是从恒河猴的中脑和脑桥部位进行的，这些猴子被训练跟踪在水平、垂直和深度（或目标聚散度）平面上移动的视觉目标。最常见的具有聚散信号的神经元是会聚细胞。这些装置的发射速率与会聚角成线性比例；他们的活动不受共轭凝视变化的影响。会聚细胞活动的变化稍微先于会聚角的变化。无论这种变化是对纯粹的适应性还是差异性线索的反应，收敛细胞的活性都会随着收敛的增加而增加。发现分歧细胞的频率要低得多。这些细胞与会聚细胞相似，只是它们会降低放电率以增加会聚性。发散细胞的活动不受共轭注视方向变化的影响。在动眼核外侧的中脑网状结构中发现了会聚细胞和发散细胞的混合。大多数具有聚散信号的细胞被发现在距细胞核 1-2 毫米的范围内。这些结果支持这样的观点：共轭信号和聚散信号是独立产生的，并且在眼外运动神经元处组合。会聚细胞似乎非常适合提供附近医学直肌运动神经元所需的聚散信号。
Animals with binocular single vision use disjunctive (vergence) eye movements to align the 2 eyes on a visual target. Several lines of evidence suggest that conjugate and vergence eye movement commands are generated independently and combined at the medical rectus motoneurons. A pure vergence eye-position signal could exist, which would be proportional to the horizontal angle between the eyes (vergence angle) without regard to the direction of conjugate gaze. Neurons that carry a pure vergence signal were studied. Extracellular unit recordings were made from midbrain and pontine sites in [rhesus] monkeys trained to track visual targets moving in the horizontal, vertical, and depth (or target vergence) planes. The most commonly encountered neuron that had a vergence signal was the convergence cell. These units had a firing rate that was linearly proportional to the convergence angle; their activity was unaffected by changes in conjugate gaze. Changes in convergence cell activity preceded the change in vergence angle slightly. Convergence cell activity increased for increased convergence regardless of whether the change was in response to purely accommodative or disparity cues. Divergence cells were found far less frequently. These cells were similar to convergence cells except that they decreased their firing rate for increases in convergence. The activity of divergence cells was unaffected by changes in the direction of conjugate gaze. Both convergence and divergence cells were found, intermixed, in the mesencephalic reticular formation just outside the oculomotor nucleus. Most cells with a vergence signal were found within 1-2 mm of the nucleus. These results support the view that conjugate and vergence signals are generated independently, and are combined at the extraocular motoneurons. Convergence cells seem ideally suited to provide the vergence signal required by the nearby medical rectus motoneurons.