Electrolytic lesions to the optic chiasm affect circadian locomotor rhythms in lizards.
Electrolytic lesions to 85-95% of both optic nerves at the level of the optic chiasm (OC-X) induce a significant shortening of the free-running period (tau) of locomotor rhythms in Podarcis sicula held in constant temperature (29 degrees C) and constant darkness. Together with previous data in P. sicula, showing that retinalectomy (RET-X) in constant darkness also mostly induces a shortening of tau, the present results demonstrate that the retinae play a central role in the control of behavioural circadian rhythmicity independently of light perception. The fact that OC-X and RET-X affect locomotor rhythms in the same way (mostly by shortening tau), strongly supports the contention that the influence of the retinae on the circadian system is neurally mediated.
Minutini
L
L
Dipartimento di Scienze del Comportamento, Animale e dell'Uomo, Università di Pisa, Italy.
Innocenti
A
A
Bertolucci
C
C
Foà
A
A
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D003624:Darkness; D004572:Electrolysis; D008116:Lizards / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009897:Optic Chiasm / Q000502:physiology*; D013696:Temperature