Circadian regulation of visually evoked potentials in the domestic pigeon, Columba livia.
J Biol Rhythms
; 15(4): 317-28, 2000 Aug.
Article
em En
| MEDLINE
| ID: mdl-10942263
ABSTRACT
The avian circadian and visual systems are integrally related and together influence many aspects of birds' behavior and physiology. Certainly, light cycles and their visual perception are the major zeitgebers for circadian rhythms, but do circadian rhythms affect vision? To assess whether visual function is regulated on a circadian basis, flash-evoked electroretinograms (ERGs) and vision-evoked potentials (VEPs) from the optic tectum (TeO) were recorded simultaneously in domestic pigeons at different circadian phases in a light-dark regime (LD) and in constant darkness (DD), while feeding activity was measured to determine circadian phase. In both LD and DD, the amplitudes of ERG b-waves were higher during the day than at night and latencies of a- and b-waves were longer at night. The median effective intensity for ERG a-wave was marginally higher during the day than during the night, indicating greater sensitivity at night, but this rhythm did not persist in DD. The amplitudes of TeO VEPs were also greater during the day, and latencies were greater at night in LD and DD. Together, the data indicate that a circadian clock regulates pigeon visual function at several integrative levels.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Columbidae
/
Colículos Superiores
/
Ritmo Circadiano
/
Potenciais Evocados Visuais
Limite:
Animals
Idioma:
En
Ano de publicação:
2000
Tipo de documento:
Article