Organization of the Human Circadian System
Abstract
In brains obtained from late gestation fetuses (33-36 weeks), newborns and young individuals to approximately age 50, the SCN is virtually always identifiable as a discrete nucleus with clear boundaries. From age-50-90, it is sometimes evident and and sometimes not evident in the material. We have completed analysis of 22 hypothalami prepared for immunocytochemistry, including quantitative analysis. Sections are routinely stained for VIP, VP, NPY and NT. This analysis has revealed several interesting aspects of the human SCN. First, in contrast to what is found in Nissl material, the SCN is always evident as a distinct nucleus in immunocytochemical material. Second, it appears as the first component of the hypothalamus to be found in a rostrocaudal set of coronal sections. Third, the human SCN is characterized by four separate populations of neurons that have different peptide content. These neuronal populations have a different distribution in the nucleus. In contrast to all other mammals, the human SCN contains a population of NPY + neurons that overlaps the VIP + group but extends dorsally beyond it in the center on the SCN. Among the NPY + neurons are scattered coarse fibers and varicosities and a fairly dense plexus of very fine fibers and small varicosities. These are very similar in morphology to GHT projections in other mammals, particularly the cat and monkey.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 31, 1993
- Accession Number
- ADA264675
Entities
People
- Robert Y. Moore
Organizations
- University of Pittsburgh