Fresh frozen sections of the temporal lobe from patients undergoing surgical resection for the control of epilepsy were used as a substrate in tissue culture to test for neurite growth-promoting activity. Robust neurite growth from ganglia of embryonic chicks was observed on gray matter regions of the sections and little growth was observed on white matter regions. These results indicate that the dichotomy between gray and white matter regions of the mature central nervous system in supporting neurite growth is present in human brain tissue and supports the general hypothesis that white matter in the mature central nervous system inhibits neurite regeneration but that gray matter will support neurite growth.