Gioanni H
Département de Neurochimie-Anatomie, Université Pierre et Marie Curie, Paris, France.
Exp Brain Res. 1988;69(3):567-82. doi: 10.1007/BF00247310.
A quantitative study of horizontal and vertical optokinetic nystagmus (OKN) and optocollic reflex (OCR) has been performed in the pigeon using the search-coil technique. The reflexes were analysed in response to either velocity steps or sinusoidal stimulation. Results show that: 1. In response to a velocity step stimulation, the slow phase velocity of both OKN and OCR increases gradually to reach a steady state level. When the stimulation stops in the dark, After Responses (OKAN-I, OKAR-I) occur. Time constants of the OKN charge (or OCR charge) and of the After Responses are lower for vertical than for horizontal responses. 2. In the free-head condition, both the head and the eye display a synchronized nystagmus which add their effects. However, the head reflex (OCR) accounts for about 80-90% of the entire linear gaze response (head + eye), except for the vertical steady state responses which are wholly accomplished by the head (OCR). 3. Both closed-loop and open-loop gains of steady state responses are higher for horizontal than for vertical reflexes. Vertical OCR, horizontal OKN and vertical OKN show properties of binocular integration, the response gain being higher for binocular than for monocular stimulations. By contrast, the horizontal OCR shows little binocular integration but displays a higher response gain for monocular stimulation, compared to horizontal OKN. 4. The horizontal OKN elicited by both monocular and binocular stimulation is asymmetrical, the gain being higher when the eye is driven by a temporo-nasal stimulation. In contrast, both vertical OKN and vertical OCR are practically symmetrical. 5. While both the gain of horizontal OKN and its linear range (up to 20 degrees/s) are improved when the head is free (gaze gain close to 1 up to 40 degrees/s), the vertical OKN and the vertical OCR have similar gain profiles and similar domains of linearity (up to 10 degrees/s). 6. In response to increasing the frequency of a sinusoidal stimulation at constant peak velocity, all the reflexes display a drop in gain and a strong increase of phase lag. The phase increase is greater for horizontal than for vertical reflexes. On the other hand, both gain and phase are higher for OCR than for OKN, both in the horizontal plane as well as in the vertical plane. 7. For sinusoidal stimulations, when the peak velocity (PV) is increased at a constant frequency (0.03 Hz), nonlinearities appear (drop in gain, phase increase) both for OKN and OCR.(ABSTRACT TRUNCATED AT 400 WORDS)
利用搜索线圈技术对鸽子的水平和垂直视动性眼震（OKN）以及视顶盖反射（OCR）进行了定量研究。针对速度阶跃或正弦刺激对这些反射进行了分析。结果表明：1. 对速度阶跃刺激的反应中，OKN和OCR的慢相速度均逐渐增加至稳态水平。当在黑暗中刺激停止时，会出现后效应（OKAN-I、OKAR-I）。OKN（或OCR）电荷以及后效应的时间常数在垂直反应中比水平反应更低。2. 在自由头部条件下，头部和眼睛均表现出同步性眼震，二者效应叠加。然而，头部反射（OCR）在整个线性注视反应（头部 + 眼睛）中占约80 - 90%，垂直稳态反应除外，其完全由头部（OCR）完成。3. 稳态反应的闭环和开环增益在水平反射中比垂直反射更高。垂直OCR、水平OKN和垂直OKN表现出双眼整合特性，双眼刺激时的反应增益高于单眼刺激。相比之下，水平OCR几乎没有双眼整合，但与水平OKN相比，单眼刺激时反应增益更高。4. 单眼和双眼刺激引发的水平OKN不对称，当眼睛由颞侧 - 鼻侧刺激驱动时增益更高。相反，垂直OKN和垂直OCR实际上是对称的。5. 当头部自由时，水平OKN的增益及其线性范围（高达20度/秒）均得到改善（注视增益在高达40度/秒时接近1），而垂直OKN和垂直OCR具有相似的增益曲线和相似的线性范围（高达10度/秒）。6. 在恒定峰值速度下增加正弦刺激的频率时，所有反射的增益均下降且相位滞后大幅增加。水平反射的相位增加比垂直反射更大。另一方面，在水平平面和垂直平面中，OCR的增益和相位均高于OKN。7. 对于正弦刺激，当在恒定频率（0.03赫兹）下增加峰值速度（PV）时，OKN和OCR均出现非线性（增益下降、相位增加）。（摘要截选至400字）
