Swindale N V, Mitchell D E
Department of Ophthalmology, University of British Columbia, Vancouver, Canada.
Exp Brain Res. 1994;99(3):399-410. doi: 10.1007/BF00228976.
Receptive field properties of extracellularly recorded units in the visual cortex (area 17) of cats made bilaterally amblyopic by a variety of rearing conditions were measured and compared with the properties of units in normal cats. Properties studied included sensitivity to vernier offset, response facilitation to increasing bar length, receptive field size, responsiveness to moving and flashed stimuli, orientation tuning, the relation between mean firing rate and its variance, the amount of overlap of regions of on and off responsiveness in simple and complex cells, and, for flashed stimuli, latency to response onset, time to peak response, and response decay time constant. Behavioural testing of the amblyopic animals showed that spatial resolution was 2-4 times lower and vernier acuity thresholds 10-20 times greater than normal. Despite this, several neuronal response properties did not differ significantly from those in normal animals. These included peak responsiveness to moving stimuli, widths of orientation tuning curves, response variability, and latency to initial response for flashed stimuli. Other properties showed small but significant changes. Sensitivity to vernier offset (impulses per degree of offset) was reduced to nearly half its normal level; receptive field sizes increased by about 24% and an incomplete segregation of regions of on and off responsiveness was found in some cells, which made them hard to classify as simple or complex. Responses to flashed stimuli were smaller and more persistent. Their statistical significance notwithstanding, it seems unlikely that these relatively small response abnormalities in area 17 can fully account for the observed behavioural deficits.
对因多种饲养条件导致双眼弱视的猫的视觉皮层（17区）中细胞外记录单位的感受野特性进行了测量，并与正常猫的单位特性进行了比较。研究的特性包括对游标偏移的敏感性、对增加条形长度的反应易化、感受野大小、对移动和闪烁刺激的反应性、方向调谐、平均放电率与其方差之间的关系、简单细胞和复杂细胞中开反应区和关反应区的重叠量，以及对于闪烁刺激，反应起始潜伏期、反应峰值时间和反应衰减时间常数。对弱视动物的行为测试表明，其空间分辨率比正常情况低2至4倍，游标敏锐度阈值比正常情况大10至20倍。尽管如此，一些神经元反应特性与正常动物的并无显著差异。这些特性包括对移动刺激的峰值反应性、方向调谐曲线的宽度、反应变异性以及对闪烁刺激的初始反应潜伏期。其他特性则有微小但显著的变化。对游标偏移的敏感性（每度偏移的脉冲数）降低到正常水平的近一半；感受野大小增加了约24%，并且在一些细胞中发现开反应区和关反应区的分离不完全，这使得它们难以归类为简单细胞或复杂细胞。对闪烁刺激的反应较小且更持久。尽管这些差异具有统计学意义，但17区这些相对较小的反应异常似乎不太可能完全解释所观察到的行为缺陷。
