COMPENSATORY HYPERTROPHY OF THE CENTRALSTRUCTURES FOLLOWING ATROPHY OF THEMIDDLE REGION OF ONE CEREBRAL HEMISPHERE / 解剖学报

ABSTRACT

This report deals with the brain and spinal cord of a porencephalic nursling of 8months. Intermittent serial colloidin sections were cut and stained by Nissl and Weiltechniques. The left cerebral hemisphere is smaller with deeper sulci and narrower gyri. Theinsular lobe is non-existent; and the frontal parietal and temporal opercula are all miss-ing. A cavity underlies this region and communicates with the lateral ventricle beingcovered Iaterally by a thickened membrane about 4?0.8 cm in area. Most of the front-al, parietal and temporal lobes and the whole occipital lobe are present. The left pyramidal tract is undeveloped. Compensatory hypertrophy is shown byvarious central structures such as the right pyramidal tract (together with the aberrantpyramidal bundles), and the extrapyramidal gray masses-lenticular, caudate and sub-thalamic nuclei and substantia nigra. In the cerebellar system, the brachium conjunc-tivum on the left side and the red nucleus and the inferior olivary nucleus on the rightare over-developed. Other hypertrophied structures include the left gracile and cuneatenuclei, the right lemniscus medialis, together with the anterior funiculus, posterior hornand the nucleus dorsalis in the right half of the spinal cord. The postnatal heightened use of bodily organs naturally induces an over-developmentof, besides others, the central structure. With a short life-span and retarded develop-ment, the present case had a too limited activity to influence the size of its central or-gans. Moreover, a number of central nuclear masses manifest a compensatory enlarge-ment, thus indicating a heightened mitotic activity of the nerve cells in the embryonicperiod. This hypertrophy is, them, largely prenatal. The current theories of compensation such as self-regulation, substitution and trans-fer of functions, are not explanatory and, thus, unsatisfactory. Behind such concepts,there shou1d exist a more fundamental and yet unspecified factor of growth. The pre-sent study has demonstrated more facts of compensatory development than the previousauthors. As to the theories of compensation, it is better to reserve a definite judgement.