目的:研究初级视区急性毁损对猫的高级视区刺激诱导的c-fos蛋白表达的影响,探索初级视区毁损后的残留视觉(称盲视)可能机制。方法:本研究采用免疫组织化学检测了初级视区(包括17和18区)急性毁损对猫的高级视区(包括19、20和21区)中立早基因c-los蛋白基础表达量和刺激诱导的c—fos蛋白表达量的影响,以正常猫为对照。结果:急性毁损初级视区后,高级视区内c-los免疫阳性神经元密度及c—fos免疫阳性反应的光吸收值(OA)在初级视区毁损猫和正常对照猫之间无显著差异;然而,双侧初级视区毁损猫的高级视区中刺激诱导的c—fos免疫阳性神经元密度比正常猫下降了92%以上,c—fos蛋白免疫阳性反应的OA值下降了78.9%以上。结论:初级视区急性毁损后高级视区的绝大多数神经元失去了对视觉刺激的反应性,因此,初级视区毁损后出现的盲视现象可能主要与皮层下中枢至高级视区的神经通路重组有关。
Objective: To study the effects of acute primary visual cortex damage on stimulus-evoked c-los expression in the higher visual cortical areas. Methods: Immunohistochemical labelling technique was used to examine the baseline expression and stimulus-evoked expression of c-los protein in the higher visual cortex (including 19, 20, 21 area) in normal cats and cats with acute lesion of bilateral primary visual cortex ( 17, 18 area). Results: Acute lesion of primary visual cortex did not significantly change the baseline expression of c-los protein in the higher visual cortical areas. The mean density of c-los immunoreactive neurons and the mean optical absorbance (OA) value of c-los immunoreactivity exhibited no significant difference between lesioned and normal cats. However, the stimulus-evoked c-los protein expression in the higher visual cortical areas with bilateral lesion of primary visual cortex was significantly decreased compared with that in normal cats. Compared to normal cats, the mean density of c'-fos immunoreactive neurons in lesioned cats was reduced by more than 92 %, and the mean OA value decreased by more than 78. 9%. Conclusion: The results indicate that most neurons in the higher visual cortical areas lose response to visual stimulation immediately after acute lesion of primary visual cortex. Therefore, the formation of blindsight may be chiefly attributed to neural pathway reorganizations after the loss of input from primary visual cortex.