Fine structure based on the Golgi method of the abnormal cortex and heterotopic nodules in pachygyria.

The structure of the four-layer abnormal cerebral cortex and of the heterotopic cerebral nodules in pachygyria has been studied by means of the Golgi method. The external cellular layer is formed by neurons closely mimicking, in morphology and distribution, those observed in layers V-VI of the normal cortex, although major abnormalities in orientation of pyramidal cells are a prominent abnormal feature. The internal cortical cellular layer is composed of several neuron types in which no distinctive layered organization can be detected. Heterotopic cerebral nodules are formed by neurons of the cortical types with random orientation of their cellular processes. Some extrinsic axons have been demonstrated, thus suggesting lack of isolation of heterotopic nodules.