[Characteristics of neuronal structure and afferent connections of the central gray matter of cat's brain stem].

The central grey matter was studied in kittens and adult cats by Golgi method after destruction of the reticular formation. Two types of neurons have been shown. One of them--similar to those of the reticular formation--from the external two thirds of the substance. Others--similar to neuroblasts--lie near the wall of the aqueduct of Sylvius. Afferent fibres running to neurons of the vertebral and lateral parts of the external zone of the central grey matter from the reticular formation zone adjacent to nuclei of the spinal pathway of the trigeminal nerve and from the caudal reticular nucleus of the pons were detected. The neurons of the internal, parietal zone of the substance are considered as haemoreceptors of the liquid cerebral medium. The material is discussed from the viewpoint of participation of the structures in question in the functional system controlling behavior of man and animals during starvation.