McCrea R A, Gdowski G T, Boyle R, Belton T
Department of Neurobiology, Pharmacology, and Physiology, University of Chicago, Chicago, Illinois 60637, USA.
J Neurophysiol. 1999 Jul;82(1):416-28. doi: 10.1152/jn.1999.82.1.416.
The firing behavior of 51 non-eye movement related central vestibular neurons that were sensitive to passive head rotation in the plane of the horizontal semicircular canal was studied in three squirrel monkeys whose heads were free to move in the horizontal plane. Unit sensitivity to active head movements during spontaneous gaze saccades was compared with sensitivity to passive head rotation. Most units (29/35 tested) were activated at monosynaptic latencies following electrical stimulation of the ipsilateral vestibular nerve. Nine were vestibulo-spinal units that were antidromically activated following electrical stimulation of the ventromedial funiculi of the spinal cord at C1. All of the units were less sensitive to active head movements than to passive whole body rotation. In the majority of cells (37/51, 73%), including all nine identified vestibulo-spinal units, the vestibular signals related to active head movements were canceled. The remaining units (n = 14, 27%) were sensitive to active head movements, but their responses were attenuated by 20-75%. Most units were nearly as sensitive to passive head-on-trunk rotation as they were to whole body rotation; this suggests that vestibular signals related to active head movements were cancelled primarily by subtraction of a head movement efference copy signal. The sensitivity of most units to passive whole body rotation was unchanged during gaze saccades. A fundamental feature of sensory processing is the ability to distinguish between self-generated and externally induced sensory events. Our observations suggest that the distinction is made at an early stage of processing in the vestibular system.
在三只头部可在水平面自由移动的松鼠猴中，研究了51个与眼动无关的中枢前庭神经元的放电行为，这些神经元对水平半规管平面内的被动头部旋转敏感。将自发注视扫视期间单位对主动头部运动的敏感性与对被动头部旋转的敏感性进行了比较。大多数单位（测试的29/35）在同侧前庭神经电刺激后以单突触潜伏期被激活。九个是前庭脊髓单位，在C1水平对脊髓腹内侧索进行电刺激后被逆向激活。所有单位对主动头部运动的敏感性均低于对被动全身旋转的敏感性。在大多数细胞（37/51，73%）中，包括所有九个已识别的前庭脊髓单位，与主动头部运动相关的前庭信号被抵消。其余单位（n = 14，27%）对主动头部运动敏感，但其反应减弱了20 - 75%。大多数单位对被动头对躯干旋转的敏感性与对全身旋转的敏感性几乎相同；这表明与主动头部运动相关的前庭信号主要通过减去头部运动传出副本信号而被抵消。在注视扫视期间，大多数单位对被动全身旋转的敏感性不变。感觉处理的一个基本特征是能够区分自我产生的和外部诱发的感觉事件。我们的观察结果表明，这种区分是在前庭系统处理的早期阶段进行的。
