Behavioral and physiological research on a compensatory effect for brain lesion in rats.

给3月龄两种类型的独眼大鼠进行黑白辨别任务。一种类型在出生后24小时内摘除右眼(OEB)。另一只在3月龄时右眼被摘除(OET)。在相同的成绩水平下，OeBS和OETs都能学习辨别任务。当损毁大鼠的右侧视皮层并给予受试者相同的任务时，OeBS重新学习任务的速度明显快于OETs。由于OeBS非交叉视路的分辨能力增强似乎在上述效应中起重要作用，因此采用水平-垂直辨别任务来评估OeBS和OETs的分辨能力水平。OeBS和OETs在大脑完整的情况下，都能获得对30 mm宽度条纹的辨别能力，并在对侧视皮层损伤后重新学习该任务。两组之间的再学习速度没有差异。然后，条纹的宽度逐渐减小，范围从20 mm到5 mm。结果发现，OETs识别的最小条带宽度中位数为10 mm，OeBS最小条带宽度中位数为7.5 mm。尽管OETs不能像OeBS那样分辨出最小的条纹，但他们能够分辨出比假设的条纹小三分之一的条纹。这些发现表明，我们前面提到的效应不能仅仅用分辨能力来解释。对线索的认知可能是对这一现象的一个重要术语。解决这个问题的方法现在正在我们的实验室进行。

A black-white discrimination task was given to two types of one-eyed rats at 3 months of age. One type had the right eye removed within 24 hours after brith (OEB). The other had the right eye enucleated at 3 months of age (OET). Both OEBs and OETs could learn the discrimination task at the same performance level. When the right visual cortex of the rats was lesioned and the same task was given to the subjects, OEBs could relearn the task significantly faster than OETs. It was considered that this effect was lead by reorganization of the optic pathways, especially of the uncrossed visual pathways.As it was seemed that an increased resolution capacity of uncrossed visual pathways in OEBs had an important role in the above mentioned effect, a horizontal-vertical discrimination task was employed to assess the levels of resolution capacity of OEBs and OETs. Both OEBs and OETs with their brain intact could acquire the discrimination between the stripes with a width of 30mm and relearn the task after the visual cortex contralateral to the remaining eye was lesioned. There was no difference in the relearning speed between the groups. Then, a width of stripes was gradually reduced ranging from 20mm to 5mm. It was found that the median width of the smallest stripes for OETs to discriminate was 10mm, and that of OEBs 7.5mm. Although OETs could not discriminate the smallest stripes which OEBs could, they were able to discriminate stripes one third smaller than those hypothesized. These findings suggested that our previously mentioned effect could not be explained only by resolution capacity. Cognition of the cue might be an important term upon the phenomenon. The approach to this problem is now undertaken in our laboratory.