Mitchell Donald E, Kennie Jan, Kung Diane
Psychology Department, Dalhousie University, Halifax, NS, Canada.
Curr Biol. 2009 Apr 28;19(8):645-9. doi: 10.1016/j.cub.2009.02.038. Epub 2009 Mar 12.
The accurate representation of the motion of external objects is one of the more important tasks of the visual areas of the brain because motion by itself can provide sufficient information for discriminating visual forms and hence breaking camouflage. Whereas the analysis of the motion of single small elements can occur in primary visual cortex (V1), the perception of a common direction of global motion of some visual elements among many is supported by extrastriate cortical areas [1, 2]. Humans treated for binocular congenital cataracts afterward exhibit extreme deficits of global motion, but after monocular cataracts, the deficits are minimal [3]. These observations suggest a need for normal early patterned visual experience through at least one eye for global motion perception to develop in a typical fashion. We investigated this role for early experience and its timing on kittens that were deprived of light or patterned light at different ages. Such deprivation in the first 6 weeks resulted in long-lasting (>2 yr) profound deficits of perception of global motion but no apparent effects on the perception of simple unidirectional motion. Contrary to current opinion, sensitive periods to visual deprivation in primary and extrastriate cortex may be of similar duration.
准确呈现外部物体的运动是大脑视觉区域较为重要的任务之一，因为运动本身就能提供足够信息来辨别视觉形态，进而识破伪装。虽然对单个小元素运动的分析可在初级视皮层（V1）中进行，但许多视觉元素中某些视觉元素全局运动共同方向的感知则由纹外皮层区域支持[1,2]。双眼先天性白内障患者术后会表现出严重的全局运动缺陷，但单眼白内障患者术后的缺陷则微乎其微[3]。这些观察结果表明，至少通过一只眼睛获得正常的早期有图案视觉体验，对于以典型方式发展全局运动感知是必要的。我们研究了早期体验及其时机对在不同年龄被剥夺光线或有图案光线的小猫的作用。在出生后前6周进行这种剥夺会导致长期（>2年）严重的全局运动感知缺陷，但对简单单向运动的感知没有明显影响。与当前观点相反，初级视皮层和纹外皮层中视觉剥夺的敏感期可能持续时间相似。
