[Distribution of efferent neurons of different types in the motor cortex of the cat].

Distribution of efferent neurones of different categories was studied in the cat sensorimotor cortex: pyramidal and extrapyramidal systems and cortico-thalamic cells, whose axons end in the ventroposterolateral nucleus and medial geniculate body. In the major part of cortical microareas (88%) several output cells were found which could belong equally to one or several different categories. In some vertical cortical tracks no output neurones of the investigated categories were discovered. In tracks with efferent neurones, cortical areas with a definite set of output cells usually represented cylinders of 500-700 mcm in height. Separate microareas differed from each other by sets of fast or slow cells.