Maze learning in rats hemidecorticated in infancy.

Publisher Website
Google Scholar
Abstract
In this expt. 67 rats were hemidecorticated on the 22d day of life in 4 ways: unilateral, diagonal, frontal. and occipital. In another 12 rats the striate areas were partially destroyed. Training on a 15-section ally maze was begun 3 mos. after the operation. Comparison of these maze scores with those of normals and animals cortically operated at adult age revealed: 1. All the animals hemidecorticated in infancy showed some retardation in maze learning but far less retardation than animals operated at adult age even with smaller lesions. 2. Diagonal hemi-decortication was more detrimental than other types. 3. A small cortical lesion in the striate area inflicted in infancy was far less detrimental than a similar lesion suffered at adult age. Hemidecorticated animals behaved normally to casual observation. It was suggested that aside from the specific and localized functions characteristic of the various parts of the cerebral cortex, there was some general non-Jocalized and facilitating function, common to all parts. The efficiency of a mass of cerebral tissue depended, among other things, upon the intensity of its parts. The efficiency of 2 widely isolated parts (diagonal hemidecortication) was less than that of a single mass of equal amt. (unilateral, frontal, or occipital decortication). The isolated parts suffered from lack of mutual facilitation. The following possible explanations of the results were discussed: Recovery from diaschisis effect; post-natal growth of residual parts; freedom from loss of fixed habits; higher plasticity of infant brain tissue. The last was accepted as the most likely explanation. There was evidence that, because of the high functional plasticity of infant brain, integration was less closely dependent on the amt. of anatomic substratum. Integration was effected promptly and efficiently. This in adult animals was impossible due to the functional rigidity of their brain tissue.

This publication has 3 references indexed in Scilit: