Finlay A L, Jones S R, Morland A B, Ogilvie J A, Ruddock K H
Physics Department, Imperial College of Science, Technology and Medicine, London, UK.
Proc Biol Sci. 1997 Feb 22;264(1379):267-75. doi: 10.1098/rspb.1997.0038.
We have investigated visual responses to moving stimuli presented to the normal hemifield of a hemianope, GY, who exhibits residual visual function in his right, 'blind' hemifield. Preliminary experiments established that his perception of moving stimuli localized in his 'blind' hemifield is retained when a similar stimulus is presented simultaneously in the normal hemifield. In response to a grating stimulus moving horizontally towards fixation in the non-foveal region of the normal, left hemifield, he perceives in addition to a normal motion percept in the left hemifield, a sensation of movement localized in the right hemifield. Qualitatively, this latter is indistinguishable from responses elicited by direct stimulation localized within his 'blind' hemifield by moving stimuli. We have investigated the characteristics of the mechanisms which induce the 'blind' field component of GY's responses to stimulation of the normal hemifield. We show that GY's sensitivity for detection of movement localized within his 'blind' hemifield is dependent on the direction of movement, the contrast and the velocity of a grating presented to the normal hemifield. No induced effects were recorded in response to colour or to non-moving, flickering stimuli. We examine the possible contribution of scattered light to our observations, and eliminate this factor by consideration of our experimental results. We discuss the neural mechanisms which may be involved in this response.
我们研究了半侧盲患者GY对呈现于其正常视野半侧的移动刺激的视觉反应，该患者在其右侧“盲”视野中表现出残余视觉功能。初步实验表明，当在正常视野中同时呈现类似刺激时，他对位于其“盲”视野中的移动刺激的感知得以保留。当在正常的左侧视野的非中央凹区域有一个水平向注视点移动的光栅刺激时，除了在左侧视野中能感知到正常的运动知觉外，他在右侧视野中还能感觉到一种运动。从性质上讲，后者与通过移动刺激直接刺激其“盲”视野内所引发的反应并无区别。我们研究了诱导GY对正常视野刺激反应中“盲”视野成分的机制的特征。我们发现，GY对其“盲”视野内运动检测的敏感度取决于运动方向、呈现于正常视野的光栅的对比度和速度。对颜色或静止闪烁刺激未记录到诱导效应。我们研究了散射光对我们观察结果的可能影响，并通过考虑实验结果排除了这一因素。我们讨论了可能参与这种反应的神经机制。
