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首页> 外文期刊>Journal of Neurophysiology >Human vestibuloocular reflex and its interactions with vision and fixation distance during linear and angular head movement.
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Human vestibuloocular reflex and its interactions with vision and fixation distance during linear and angular head movement.

机译：在线性和成角度的头部运动过程中，人前庭反射及其与视力和注视距离的相互作用。

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Human vestibuloocular reflex and its interactions with vision and fixation distance during linear and angular head movement. J. Neurophysiol. 80: 2391-2404, 1998. The vestibuloocular reflex (VOR) maintains visual image stability by generating eye movements that compensate for both angular (AVOR) and linear (LVOR) head movements, typically in concert with visual following mechanisms. The VORs are generally modulated by the "context" in which head movements are made. Three contextual influences on VOR performance were studied during passive head translations and rotations over a range of frequencies (0.5-4 Hz) that emphasized shifting dynamics in the VORs and visual following, primarily smooth pursuit. First, the dynamic characteristics of head movements themselves ("stimulus context") influence the VORs. Both the AVOR and LVOR operate with high-pass characteristics relative to a head velocity input, although the cutoff frequency of the AVOR (<0.1 Hz) is far below that of the LVOR ( approximately 1 Hz), and both perform well at high frequencies that exceed, but complement, the capabilities of smooth pursuit. Second, the LVOR and AVOR are modulated by fixation distance, implemented with a signal related to binocular vergence angle ("fixation context"). The effect was quantified by analyzing the response during each trial as a linear relationship between LVOR sensitivity (in deg/cm), or AVOR gain, and vergence (in m-1) to yield a slope (vergence influence) and an intercept (response at 0 vergence). Fixation distance (vergence) was modulated by presenting targets at different distances. The response slope rises with increasing frequency, but much more so for the LVOR than the AVOR, and reflects a positive relationship for all but the lowest stimulus frequencies in the AVOR. A third influence is the context of real and imagined targets on the VORs ("visual context"). This was studied in two ways-when targets were either earth-fixed to allow visual enhancement of the VOR or head-fixed to permit visual suppression. The VORs were assessed by extinguishing targets for brief periods while subjects continued to "fixate" them in darkness. The influences of real and imagined targets were most robust at lower frequencies, declining as stimulus frequency increased. The effects were nearly gone at 4 Hz. These properties were equivalent for the LVOR and AVOR and imply that the influences of real and imagined targets on the VORs generally follow low-pass and pursuit-like dynamics. The influence of imagined targets accounts for roughly one-third of the influence of real targets on the VORs at 0.5 Hz.
机译：在线性和成角度的头部运动过程中，人前庭反射及其与视力和注视距离的相互作用。 J.神经生理学。 80：2391-2404，1998。前庭反射（VOR）通过产生可补偿角向（AVOR）和线性（LVOR）头部运动的眼睛运动来维持视觉图像稳定性，通常与视觉跟随机制配合使用。 VOR通常由进行头部运动的“上下文”调制。研究了在一定频率范围内（0.5-4 Hz）被动头部平移和旋转期间对VOR性能的三个环境影响，这些频率强调了VOR和视觉跟随（主要是平滑追随）中的移动动态。首先，头部运动本身的动态特征（“刺激环境”）会影响VOR。尽管AVOR的截止频率（<0.1 Hz）远低于LVOR的截止频率（约1 Hz），但AVOR和LVOR均相对于磁头速度输入具有高通特性。超越但补充了平滑追击的能力。其次，LVOR和AVOR由固定距离调制，该固定距离由与双目发散角（“固定环境”）有关的信号实​​现。通过分析每个试验中的响应，将其作为LVOR灵敏度（以度/厘米为单位）或AVOR增益与会聚（以m-1为单位）之间的线性关系来量化效果，以产生斜率（会聚影响）和截距（回应）在0收敛）。通过以不同距离呈现目标来调节固视距离（收敛）。响应斜率随频率的增加而增加，但对于LVOR而言，其响应幅度要比AVOR大得多，并且反映了AVOR中除了最低刺激频率之外的所有其他正相关关系。第三个影响是VOR上实际目标和预期目标的上下文（“可视上下文”）。这是通过两种方式进行研究的：将目标固定在地面以允许视觉增强VOR，或者将目标固定在头部以允许视觉抑制。通过短暂消灭目标，同时受试者继续在黑暗中“固定”目标来评估VOR。真实目标和想象目标的影响在较低频率下最强，随着刺激频率的增加而降低。在4 Hz时，效果几乎消失了。这些特性对于LVOR和AVOR是等效的，这意味着真实目标和预期目标对VOR的影响通常遵循低通和类似追赶的动力学。假想目标的影响大约占实际目标在0.5 Hz时对VOR的影响的三分之一。

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