Wenzel R, Bartenstein P, Dieterich M, Danek A, Weindl A, Minoshima S, Ziegler S, Schwaiger M, Brandt T
Department of Nuclear Medicine, Technical University, Munich, Germany.
Brain. 1996 Feb;119 ( Pt 1):101-10. doi: 10.1093/brain/119.1.101.
Prompted by the observation of decreased glucose metabolism in the striate and extrastriate visual cortex in a patient with opsoclonus, we studied the influence of involuntary eye movements on visual cortex activity. Repeated measurements of cerebral blood flow (CBF) by PET were performed in 12 healthy volunteers using H2(15)O-bolus technique after ear canal irrigation with ice cold or warm (44 degrees C) water with the subjects eyes closed. In addition to blood flow increases in areas involved in central vestibular processing, statistical subtraction analysis revealed a nearly symmetrical, bilateral, highly significant decrease in the occipital cortex covering Brodmann areas 17, 18, and 19 after ice water stimulation of either ears. Region of interest analysis revealed in all subjects a mean decrease in regional CBF (rCBF) of 12.8% (range 4.6-21.0%) in these areas. A similar but less pronounced effect (mean rCBF decrease in visual cortex 4.8%, range 1.1-11.5%) was observed after warm water irrigation. The observations suggest that deactivation of the visual cortex is induced by involuntary ocular oscillations. This deactivation is not dependent on changes of the retinal input (eyes closed). The physiological significance of this hitherto unknown phenomenon may be the protection from inadequate visual input (oscillopsia) during involuntary ocular oscillations.
受一名眼阵挛患者纹状和纹状外视觉皮层葡萄糖代谢降低的观察结果启发，我们研究了不自主眼球运动对视觉皮层活动的影响。在12名健康志愿者闭眼的情况下，用冷（冰）水或温水（44摄氏度）冲洗耳道后，使用H2(15)O团注技术通过PET对脑血流量（CBF）进行重复测量。除了参与中枢前庭处理区域的血流增加外，统计减法分析显示，在双耳冰水刺激后，覆盖Brodmann 17、18和19区的枕叶皮层出现近乎对称、双侧、高度显著的减少。感兴趣区域分析显示，所有受试者这些区域的局部脑血流量（rCBF）平均降低12.8%（范围4.6 - 21.0%）。温水冲洗后观察到类似但不太明显的效应（视觉皮层rCBF平均降低4.8%，范围1.1 - 11.5%）。这些观察结果表明，不自主眼球振荡可导致视觉皮层失活。这种失活不依赖于视网膜输入的变化（闭眼）。这种迄今未知现象的生理意义可能是在不自主眼球振荡期间保护免受不适当的视觉输入（视振荡）。
