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首页> 外文期刊>Investigative ophthalmology & visual science >Flicker-evoked responses of human optic nerve head blood flow: luminance versus chromatic modulation.
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Flicker-evoked responses of human optic nerve head blood flow: luminance versus chromatic modulation.

机译：人类视神经头血流的闪烁诱发反应：亮度与色度调制。

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PURPOSE. To determine the response of human optic nerve head blood flow (R:F(onh)) to heterochromatic equiluminant flicker modulation and compare it to the response induced by pure luminance flicker. METHODS. In five normal volunteers, F(onh) measured at the neuroretinal rim was monitored continuously by laser Doppler flowmetry. Stimuli were generated by green and red light emitting diodes and delivered to the fundus in Maxwellian view (field of 25(o)). Both green (G:) and red (R:) illuminances were square-wave modulated, 180(o) out of phase, with a maximum value of 10.4 for G: and 2.64 lux for R: Flicker frequency was varied from 2 Hz to 40 Hz. R:F(onh) was defined as the change in F(onh) during stimulation relative to the prestimulus F(onh). RESULTS. Defining the color ratio r as R:/(R: + G:), the R:F(onh), measured for a 15-Hz flicker, was largest at pure luminance (r = 0 and 1), declined at mixed luminance and chromatic modulations, and reached a secondary maximum at r = 0.45, the value of psychophysical equiluminance. R:F(onh) versus flicker frequency displayed the characteristics of a low-pass function for the equiluminance flicker stimulus and of a band-pass function, with a maximum at intermediate frequencies, for the luminance flicker stimulus. CONCLUSIONS. R:F(onh) in humans can be evoked by heterochromatic flicker, modulated either in luminance or chromatic equiluminant conditions. R:F(onh) may be specific for luminance and chromatic modulations, similar to neural responses dominated by the magno- and parvocellular activity, respectively. These findings offer a new approach to study the neurovascular coupling at the optic nerve head in both physiological and diseased conditions involving predominantly or selectively the magno- and parvocellular pathways.
机译：目的。要确定人类视神经头部血流（R：F（onh））对异色等亮度闪烁调制的响应，并将其与纯亮度闪烁引起的响应进行比较。方法。在五名正常志愿者中，通过激光多普勒血流仪连续监测神经视网膜边缘的F（onh）。刺激是由绿色和红色发光二极管产生的，并以麦克斯韦视野（视野为25（o））传递到眼底。绿色（G :)和红色（R :)的照度均经过方波调制，相位差为180（o），G：的最大值为10.4，R：的最大值为2.64 lux。闪烁频率从2 Hz变为40赫兹R：F（onh）定义为刺激期间F（onh）相对于刺激前F（onh）的变化。结果。将色比r定义为R：/（R：+ G :)，针对15 Hz闪烁测量的R：F（onh）在纯亮度（r = 0和1）下最大，而在混合亮度下下降和色度调制，并在r = 0.45（心理物理平衡值）达到次要最大值。 R：F（onh）相对于闪烁频率显示了亮度闪烁刺激的低通函数的特性和等值闪烁激励的带通函数（在中频处最大）。结论。人类的R：F（onh）可以通过在亮度或色度等照度条件下进行调制的异色闪烁来诱发。 R：F（onh）可能特定于亮度和色度调制，类似于分别由巨细胞和小细胞活动占主导的神经反应。这些发现提供了一种新的方法来研究在生理和疾病条件下（主要或选择性地涉及到大细胞和小细胞途径）的视神经头部的神经血管耦合。

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