Age-related changes in the cytoarchitectonics of the human sensorimotor cortex.

The projection zones of the movement analyzer show a level of maturity which is required for maintaining the self-regulatory processes in children from the first days of life [4, 8]. The cytoarchitectonics of the motor zone of the cerebral cortex have been studied in a small number of people and at limited ages [1, 2, 4, 10]. One of the leading age-related changes consists of changes in neuronal and interneuronal connections, which have significant influences on the systems organization of the brain and its function as an integral organ. Pyramidal neurons are regarded as the main universal type of cortical neuron, in which the structure of the receptive surface supports transmission of a wide range of polymodal signals [1]. Large pyramidal neurons in layers III and IV can establish connections with all the neurons in a column of cells, which apparently leads to complete and reliable functional interactions between neurons [1, 6]. The aim of the present work was to study the quantitative changes in pyramidal neurons in layers III and IV in various fields of the human sensorimotor cortex from birth to the age of 20 years.