Involvement of the primary optic tracts in mediation of light effects on hamster orcadian rhythms
- 31 Downloads
The effects of primary optic tract (POT) interruption on entrainment of circadian rhythms have been studied in rats (Stephan and Zucker, 1972a; Moore and Eichler, 1972). These studies concluded that the POT are not involved in the mediation of photic entrainment.
The present study assessed the effects of POT interruption on entrainment, phase-shifting and free-runs of activity in male golden hamsters,Mesocricetus auratus.
Several hamsters that sustained complete bilateral POT interruptions showed unusually long active phases that extended into the light phase of the light-dark (LD) cycle, or showed a long phase lead of activity onset relative to the D phase.
The periods (τ) of the free-running rhythms of these hamsters were unusually long. The combination of longτ's and altered entrainment are not explicable in terms of alterations in light sensitivity according to predictions from the Circadian Rule.
An explanation for these results is possible in terms of alterations in the coupling of two oscillators. One model of entrainment (Pittendrigh, 1974) suggests that such coupling is involved in the control of both entrainment and the periodicity of free-running rhythms.
KeywordsCircadian Rhythm Active Phasis Zucker Optic Tract Light Phase
Unable to display preview. Download preview PDF.
- Aschoff, J.: The phase-angle difference in circadian periodicity. In: Circadian clocks (ed. J. Aschoff), pp. 262–276. Amsterdam: North Holland 1965Google Scholar
- Chase, P.A., Seiden, L.S., Moore, R.Y.: Behavioral and neuroendocrine responses to light mediated by separate visual pathways in the rat. Physiol. Behav.4, 949–952 (1969)Google Scholar
- Hoffmann, K.: Overt circadian frequencies and the circadian rule. In: Circadian clocks (ed. J. Aschoff), pp. 87–94. Amsterdam: North Holland 1965Google Scholar
- Moore, R.Y.: Visual pathways and the central neural control of diurnal rhythms. In: The neurosciences: Third study program (eds. F.O. Schmitt, F.G. Worden), pp. 537–542. Cambridge, Mass: MIT Press 1974Google Scholar
- Moore, R.Y., Eichler, V.B.: Loss of a circadian adrenal corticosterone rhythm following suprachiasmatic lesions in the rat. Brain Res.42, 201–206 (1972)Google Scholar
- Moore, R.Y., Klein, D.C.: Visual pathways and the central neural control of a circadian rhythm in pineal serotonin N-acetyltransferase activity. Brain Res.71, 17–33 (1974)Google Scholar
- Pittendrigh, C.S.: Circadian oscillations in cells and the circadian organization of multicellular systems. In: The neurosciences: Third study program (eds. F.O. Schmitt, F.G. Worden), pp. 437–458. Cambridge, Mass.: MIT Press (1974)Google Scholar
- Pittendrigh, C.S., Daan, S.: A functional analysis of circadian pacemakers in nocturnal rodents. J.comp. Physiol.106, 333–355 (1976)Google Scholar
- Rusak, B.: The role of the suprachiasmatic nuclei in the generation of circadian rhythms in the golden hamster,Mesocricetus auratus. J. comp. Physiol.118, 145–164 (1977)Google Scholar
- Stephan, F.K., Zucker, I.: Rat drinking rhythms: Central visual pathways and endocrine factors mediating responsiveness to environmental illumination. Physiol. Behav.8, 315–326 (1972a)Google Scholar
- Stephan, F.K., Zucker, I.: Circadian rhythms in drinking behavior and locomotor activity of rats are eliminated by hypothalamic lesions. Proc. nat. Acad. Sci. (Wash.)69, 1583–1586 (1972b)Google Scholar
- Stephan, F.K., Zucker, I.: Endocrine and neural mediation of the effects of constant light on water intake of rats. Neuroendocrinol.14, 44–60 (1974)Google Scholar
- Swanson, L.W., Cowan, W.M., Jones, E.G.: An autoradiographic study of the efferent connections of the ventral lateral geniculate nucleus in the albino rat and the cat. J. comp. Neurol.156, 143–164 (1974)Google Scholar
- Truex, R.C., Carpenter, M.B.: Human neuroanatomy, pp. 673. Baltimore: Williams and Wilkins 1969Google Scholar
- Wever, R.: A mathematical model for circadian rhythms. In: Circadian clocks (ed. J. Aschoff), pp. 47–63. Amsterdam: North Holland 1965Google Scholar
- Whishaw, I.Q.: Light avoidance in normal rats and rats with primary visual system lesions. Physiol. Psychol.2, 143–147 (1974)Google Scholar
- Zucker, I., Rusak, B., King, R.G., Jr.: Neural bases for circadian rhythms in rodent behavior. In: Advances in psychobiology, Vol.3 (eds. A.H. Riesen, R.F. Thompson), pp. 35–74. New York: Wiley 1976Google Scholar