ISSN:
1432-1351
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Electrolytic lesions that damaged the midbrain raphe nuclei of albino rats increased the proportion of daily wheel-running behavior that occurred during the light phase of a LD 12∶:12 illumination cycle. In constant dim illumination, rats with midbrain raphe lesions generated free-running circadian locomotor rhythms with periods comparable to those of control animals. This suggests that the serotonergic projection from the midbrain raphe nuclei to the suprachiasmatic nuclei (SCN) of the hypothalamus is not critical to the generation and/or integration of circadian periodicity. Because of the disruptive effects of the lesions on activity, including the loss of a well-defined phase reference point, it was not possible to exclude more subtle effects of the raphe system on various circadian parameters. Nevertheless, the data are consistent with the hypothesis that the SCN are part of an autonomous circadian oscillatory system that does not depend on afferent input from the raphe nuclei.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00663606
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