Sireteanu R, Bäumer C, Sârbu C, Tsujimura S, Muckli L
Abteilung Neurophysiologie, Max-Planck-Institut für Hirnforschung, Deutschordenstrasse 46, Frankfurt.
Klin Monbl Augenheilkd. 2007 Oct;224(10):780-6. doi: 10.1055/s-2007-963469.
The aim of this study was to provide a description of the spatial distortions and temporal instability in amblyopic vision, and to attempt to define a cortical substrate of the spatial distortions in strabismic amblyopia.
The perceptual distortions and instabilities occurring in amblyopic vision were investigated psychophysically, by asking 17 subjects to describe and sketch their percepts. This was then visualised with an animated computer programme and validated by the subjects. In a second experiment, the cortical responses of normal observers to patterns corresponding to the spatial distortions reported by amblyopic subjects were investigated using functional magnetic resonance imaging.
Spatial distortions were more marked in strabismic than in anisometropic amblyopes or in strabismic subjects with alternating fixation. Temporal instability occurred mainly in strabismic amblyopes and affected mainly patterns with higher spatial frequencies. Experiments with functional magnetic resonance imaging showed that the patterns with the highest spatial distortions yield increased activation in the primary visual cortex of normally-sighted observers.
The results of the imaging experiment suggest that the occurrence of spatial distortions might explain the higher activation in the primary visual cortex of some amblyopic subjects. The occurrence of temporal instability in strabismic amblyopia suggests an involvement of higher-order, extrastriate visual areas of the dorsal, "where" visual pathway in amblyopia, in addition to the known deficits in the ventral, "what" visual pathway.
本研究旨在描述弱视视觉中的空间扭曲和时间不稳定性，并试图确定斜视性弱视中空间扭曲的皮质基质。
通过让17名受试者描述并勾勒他们的感知，对弱视视觉中出现的感知扭曲和不稳定性进行了心理物理学研究。然后用一个动画计算机程序将其可视化，并由受试者进行验证。在第二个实验中，使用功能磁共振成像研究了正常观察者对与弱视受试者报告的空间扭曲相对应的图案的皮质反应。
与屈光参差性弱视或交替注视的斜视受试者相比，斜视性弱视中的空间扭曲更为明显。时间不稳定性主要发生在斜视性弱视中，并且主要影响具有较高空间频率的图案。功能磁共振成像实验表明，空间扭曲最高的图案在正常视力观察者的初级视觉皮层中产生了增强激活。
成像实验结果表明，空间扭曲的出现可能解释了一些弱视受试者初级视觉皮层中较高的激活。斜视性弱视中时间不稳定性的出现表明，除了已知的腹侧“是什么”视觉通路缺陷外，弱视中背侧“在哪里”视觉通路的高阶、纹外视觉区域也参与其中。
