NTRS - NASA Technical Reports Server

Back to Results
descending projections of the hamster intergeniculate leaflet: relationship to the sleep/arousal and visuomotor systemsThe intergeniculate leaflet (IGL), homolog of the primate pregeniculate nucleus, modulates circadian rhythms. However, its extensive anatomical connections suggest that it may regulate other systems, particularly those for visuomotor function and sleep/arousal. Here, descending IGL-efferent pathways are identified with the anterograde tracer, Phaseolus vulgaris leucoagglutinin, with projections to over 50 brain stem nuclei. Projections of the ventral lateral geniculate are similar, but more limited. Many of the nuclei with IGL afferents contribute to circuitry governing visuomotor function. These include the oculomotor, trochlear, anterior pretectal, Edinger-Westphal, and the terminal nuclei; all layers of the superior colliculus, interstitial nucleus of the medial longitudinal fasciculus, supraoculomotor periaqueductal gray, nucleus of the optic tract, the inferior olive, and raphe interpositus. Other target nuclei are known to be involved in the regulation of sleep, including the lateral dorsal and pedunculopontine tegmentum. The dorsal raphe also receives projections from the IGL and may contribute to both sleep/arousal and visuomotor function. However, the locus coeruleus and medial vestibular nucleus, which contribute to sleep and eye movement regulation and which send projections to the IGL, do not receive reciprocal projections from it. The potential involvement of the IGL with the sleep/arousal system is further buttressed by existing evidence showing IGL-efferent projections to the ventrolateral preoptic area, dorsomedial, and medial tuberal hypothalamus. In addition, the great majority of all regions receiving IGL projections also receive input from the orexin/hypocretin system, suggesting that this system contributes not only to the regulation of sleep, but to eye movement control as well.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Morin, Lawrence P.
(Stony Brook University Stony Brook, New York 11794, United States)
Blanchard, Jane H.
Date Acquired
August 23, 2013
Publication Date
June 27, 2005
Publication Information
Publication: The Journal of comparative neurology
Volume: 487
Issue: 2
ISSN: 0021-9967
Subject Category
Life Sciences (General)
Funding Number(s)
Distribution Limits
Non-NASA Center
NASA Discipline Neuroscience