Two groups of corticofugal neurons identified with the pontine stimulation in the cat parietal association cortex: an intracellular HRP study.

A classification of the parietal corticofugal neurons was performed in cats under Nembutal anesthesia. Eighty-eight neurons were identified with antidromic activation by the pontine stimulation. Thirteen neurons were furthermore identified with intracellular HRP staining. In these neurons, we found the close correlation between morphological features and conduction velocities. The faster conducting group of the neurons had relatively large somata, sparsely spinous apical dendrites, tap root basal dendrites and wide apical dendritic fields. The slower group had small somata and numerous dendritic spines.