The Neurophysiology of the Mammalian Suprachiasmatic Nucleus and Its Visual Afferents

Groos, G. A.

doi:10.1007/978-3-642-68651-1_10

Cited by 18 publications

(5 citation statements)

References 28 publications

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“…Photic entrainment of drinking rhythms in the rat was not altered by damage to the geniculate region (Donaldson and Stephan, 1982) or to the primary optic tracts, which supply the retinal input to this area (Stephan and Zucker, 1972). One report described changes in SCN photic responses in rats after geniculate lesions (Groos and Mason, 1978), but a subsequent study failed to replicate these effects (Groos, 1982). Recent anatomical work has established that, in the rat and hamster, at least some of the neurons of the GHT may be identified by their immunoreactivity to neuropeptide Y (Card and Moore, 1982;Harrington et al, 1985).…”

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confidence: 86%

Lesions of the Thalamic Intergeniculate Leaflet Alter Hamster Circadian Rhythms

1986

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We have investigated the effects of destruction of the geniculo-hypothalamic tract (GHT) on the circadian system of golden hamsters. In the first experiment, intact hamsters were housed in constant darkness, and phase shifts in running-wheel activity rhythms were assessed following 15-min light pulses administered at circadian time (CT) 12 (defined as the beginning of activity), CT 14, CT 18, and CT 20. Responses to light pulses at the same CTs were then reassessed after GHT lesions. Hamsters with complete lesions showed decreases in phase advances caused by light pulses at CT 18 and CT 20. Phase delays elicited by light at CT 12 and CT 14 were not altered. In a second study, intact and GHT-ablated hamsters housed in constant light received 6-hr dark pulses at various CTs. Hamsters with complete GHT ablation showed smaller advances than controls to dark pulses centered on CT 8-10. After 110 days in constant light, 7 of 10 intact hamsters showed splitting of their activity rhythms into two components, while only 1 of the 8 similarly treated ablated hamsters displayed dissociated activity components. Ablated hamsters had significantly shorter free-running periods during the first 35 days of exposure to constant light than did the intact hamsters. These results demonstrate that destruction of the GHT in the hamster alters phase shifting in response to periods of light or dark, and they indicate a role for the GHT in mediating several photic effects on the circadian system.

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confidence: 86%

Lesions of the Thalamic Intergeniculate Leaflet Alter Hamster Circadian Rhythms

1986

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“…For example, intraocular oscillators control photoreceptor shedding in rat and Xenopus Flannery and Fisher, 1984) and retinal N-acetyltransferase activity in Xenopus (Besharse and Iuvone, 1983). Terman and Terman (1985) reported that the circadian rhythm in rat visual sensitivity persisted after lesioning the suprachiasmatic nucleus (SCN), the putative location of the circadian oscillator in the mammalian central nervous system (see Groos, 1982;Moore and Card, 1985). Intraocular circadian oscillators have also been detected in invertebrates, e.g., Aplysia (Jacklet, 1969) and Bulla (Block and Wallace, 1982).…”

Section: Location Of Circadian Oscillatorsmentioning

confidence: 99%

Circadian rhythms in the green sunfish retina.

Dearry¹,

Barlow²

1987

The Journal of General Physiology

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We investigated the occurrence of circadian rhythms in retinomotor movements and retinal sensitivity in the green sunfish, Lepomis cyanellus . When green sunfish were kept in constant darkness, cone photoreceptors exhibited circadian retinomotor movements; rod photoreceptors and retinal pigment epithelium (RPE) pigment granules did not. Cones elongated during subjective night and contracted during subjective day. These results corroborate those of Burnside and Ackland (1984. Investigative Ophthalmology and Visual Science. 25 :539-545). Electroretinograms (ERGs) recorded in constant darkness in response to dim flashes (X = 640 nm) exhibited a greater amplitude during subjective night than during subjective day. The nighttime increase in the ERG amplitude corresponded to a 3-10-fold increase in retinal sensitivity . The rhythmic changes in the ERG amplitude continued in constant darkness with a period of -24 h, which indicates that the rhythm is generated by a circadian oscillator . The spectral sensitivity of the ERG recorded in constant darkness suggests that cones contribute to retinal responses during both day and night. Thus, the elongation of cone myoids during the night does not abolish the response of the cones. To examine the role of retinal efferents in generating retinal circadian rhythms, we cut the optic nerve. This procedure did not abolish the rhythms of retinomotor movement or of the ERG amplitude, but it did reduce the magnitude of the nighttime phases of both rhythms. Our results suggest that more than one endogenous oscillator regulates the retinal circadian rhythms in green sunfish. Circadian signals controlling the rhythms may be either generated within the eye or transferred to the eye via a humoral pathway.

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“…We have attempted to integrate experimental data from different fields-visual system neuroanatomy and physiology, retinal and pineal neurochemistry, psychophysics, and circadian physiology-which, when taken together, lend plausibility to the existence of a mammalian ocular timing system. Certain retinal oscillator functions may be capable of self-sustained circadian timing without direct input into the SCN, while still serving as a dynamic gate for the amount of light information available to the SCN (Groos, 1982;Groos and Meijer, 1985). Under a light-dark (LD) cycle, these rhythms attain a reliable phase position, which can be shifted by changes in timing of the external photic zeitgeber.…”

Section: Introduction the Possibility Of Ocular Timingmentioning

confidence: 99%

The Visual Input Stage of the Mammalian Circadian Pacemaking System: I. Is There a Clock in the Mammalian Eye?

1991

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Threads of evidence from recent experimentation in retinal morphology, neurochemistry, electrophysiology, and visual perception point toward rhythmic ocular processes that may be integral components of circadian entrainment in mammals. Components of retinal cell biology (rod outer-segment disk shedding, inner-segment degradation, melatonin and dopamine synthesis, electrophysiological responses) show self-sustaining circadian oscillations whose phase can be controlled by light-dark cycles. A complete phase response curve in visual sensitivity can be generated from light-pulse-induced phase shifting. Following lesions of the suprachiasmatic nuclei, circadian rhythms of visual detectability and rod outer-segment disk shedding persist, even though behavioral activity becomes arrhythmic. We discuss the converging evidence for an ocular circadian timing system in terms of interactions between rhythmic retinal processes and the central suprachiasmatic pacemaker, and propose that retinal phase shifts to light provide a critical input signal.

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The Neurophysiology of the Mammalian Suprachiasmatic Nucleus and Its Visual Afferents

Cited by 18 publications

References 28 publications

Lesions of the Thalamic Intergeniculate Leaflet Alter Hamster Circadian Rhythms

Lesions of the Thalamic Intergeniculate Leaflet Alter Hamster Circadian Rhythms

Circadian rhythms in the green sunfish retina.

The Visual Input Stage of the Mammalian Circadian Pacemaking System: I. Is There a Clock in the Mammalian Eye?

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