Moore R Y
Department of Neurology, State University of New York, Stony Brook 11794.
Brain Res. 1989 May 1;486(1):190-4. doi: 10.1016/0006-8993(89)91294-8.
The intergeniculate leaflet (IGL) of the lateral geniculate complex in rodents contains neuropeptide Y-immunoreactive (NPY-IR) neurons which project to the suprachiasmatic nucleus (SCN) of the hypothalamus. In the macaque monkey and human brain, a large portion of the pregeniculate nucleus contains NPY-IR neurons indicating that this is the primate homologue of the rodent IGL. The monkey SCN has a dense plexus of NPY-IR axons identical in location and appearance to that in rodents. As in other mammals, no NPY-IR neurons are found in the monkey SCN. In contrast, in the human SCN, the NPY-IR plexus is less dense than in the monkey and there are numerous NPY-IR neurons. This suggests that the human SCN differs in organization from that of other mammals and that the functional homologue of the mammalian geniculohypothalamic tract is local circuit NPY+ neurons within the nucleus.
