Ohzawa I, Freeman R D
Group in Neurobiology, University of California, Berkeley 94720.
J Neurosci. 1988 Jul;8(7):2507-16. doi: 10.1523/JNEUROSCI.08-07-02507.1988.
If an animal is prevented from receiving visual experience during an early developmental phase, pronounced dysfunctions are observed. Physiological tests reveal gross abnormalities in the striate cortex. Cells in visual cortex are either unresponsive of their response characteristics are erratic. Although fewer than normal numbers of binocular cells are found in cats reared with binocular lid suture, a population remains that can be activated by stimulation through either eye. We have studied cortical cells in binocularly deprived cats in order to specify monocular and binocular response characteristics. The primary hypothesis we have examined is that the abnormal response properties of these cells are a result of an irregular structure or substructure of the receptive fields. Kittens were binocularly lid-sutured soon after birth, and were studied physiologically at ages between 7 and 11 months. Standard techniques were used to record from single cells in striate cortex. Drifting gratings were presented to either eye or to both eyes together. In the latter case, the relative interocular phase was varied between the gratings so that the retinal disparity of the stimuli was changed. We confirmed the expected finding that most cells were either unresponsive or erratic in their response. Of the cells that responded, monocular tuning functions for orientation and spatial frequency of the stimulus were often irregular. However, even in these cases, binocular interaction patterns of cortical responses were nearly always highly regular and displayed phase-specific profiles. A model is presented that explains this finding and suggests how binocular deprivation may result in disorganized receptive-field structure.
如果在动物发育的早期阶段阻止其获得视觉体验，就会观察到明显的功能障碍。生理测试显示纹状皮质存在严重异常。视觉皮质中的细胞要么无反应，要么其反应特征不稳定。尽管在双眼睑缝合饲养的猫中发现的双眼细胞数量少于正常数量，但仍有一部分细胞可以通过单眼刺激而被激活。我们研究了双眼剥夺猫的皮质细胞，以确定单眼和双眼的反应特征。我们检验的主要假设是，这些细胞异常的反应特性是感受野不规则结构或亚结构的结果。小猫在出生后不久就进行了双眼睑缝合，并在7至11个月大时进行了生理研究。使用标准技术记录纹状皮质中的单细胞活动。向单眼或双眼同时呈现漂移光栅。在后一种情况下，光栅之间的相对眼间相位会发生变化，从而改变刺激的视网膜视差。我们证实了预期的发现，即大多数细胞要么无反应，要么反应不稳定。在有反应的细胞中，刺激的方向和空间频率的单眼调谐功能往往不规则。然而，即使在这些情况下，皮质反应的双眼相互作用模式几乎总是高度规则的，并显示出相位特异性特征。本文提出了一个模型来解释这一发现，并表明双眼剥夺可能如何导致感受野结构紊乱。
