Enhancement of REM sleep during extraocular light exposure in humans

Murphy, Patricia; Campbell, Scott S.

doi:10.1152/ajpregu.2001.280.6.r1606

Cited by 5 publications

(3 citation statements)

References 44 publications

(58 reference statements)

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“…Up until now, the only new positive result on the extraocular photosensitivity of the human brain was from the group that reported those effects originally. In the new study, Murphy and Campbell (2001) exposed sleeping subjects to extraocular light and showed an enhancement of REM sleep. No other group has replicated this study up until now.…”

Section: Discussionmentioning

confidence: 97%

Acute and Phase-Shifting Effects of Ocular and Extraocular Light in Human Circadian Physiology

et al. 2003

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Light can influence physiology and performance of humans in two distinct ways. It can acutely change the level of physiological and behavioral parameters, and it can induce a phase shift in the circadian oscillators underlying variations in these levels. Until recently, both effects were thought to require retinal light perception. This view was challenged by Campbell and Murphy, who showed significant phase shifts in core body temperature and melatonin using an extraocular stimulus. Their study employed popliteal skin illumination and exclusively considered phase-shifting effects. In this paper, the authors explore both acute effects and phase-shifting effects of ocular as well as extraocular light. Twelve healthy males participated in a within-subject design and received all of three light conditions--(1) dim ocular light/no light to the knee, (2) dim ocular light/bright extraocular light to the knee, and (3) bright ocular light/no light to the knee--on separate nights in random order. The protocol consisted of an adaptation night followed by a 26-h period of sustained wakefulness, during which a 4-h light pulse was presented at a time when maximal phase delays were expected. The authors found neither immediate nor phase-shifting effects of extraocular light exposure on melatonin, core body temperature (CBT), or sleepiness. Ocular bright-light exposure reduced the nocturnal circadian drop in CBT, suppressed melatonin, and reduced sleepiness significantly. In addition, the 4-h ocular light pulse delayed the CBT rhythm by -55 min compared to the drift of the CBT rhythm in dim light. The melatonin rhythm shifted by -113 min, which differed significantly from the drift in the melatonin rhythm in the dim-light condition (-26 min). The failure to find immediate or phase-shifting effects in response to extraocular light in a within-subjects design in which effects of ocular bright light are confirmed strengthens the doubts raised by other labs of the impact of extraocular light on the human circadian system.

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Section: Discussionmentioning

confidence: 97%

Acute and Phase-Shifting Effects of Ocular and Extraocular Light in Human Circadian Physiology

et al. 2003

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“…Although small, the present data suggest that extraocular light exposure may have an acute negative effect on sleep. By contrast, Murphy and Campbell (2001) reported no evidence for increased wakefulness with the effects of extraocular light exposure on sleep limited to increased REM. It is possible that the increased wakefulness observed in the present study may be explained by the switching between the fan and BiliBlanket Plus housing units and any concomitant change in stimuli at the start of the extraocular light exposure period, such as noise.…”

Section: Placebomentioning

confidence: 96%

“…If similar effects occur with extraocular light exposure, then this may limit its clinical application. At present, our understanding of the effects of extraocular light exposure on sleep is restricted to one study by Murphy and Campbell (2001). Murphy and Campbell examined the effect of a 3-h pulse of light behind each knee on sleep in 14 subjects.…”

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confidence: 99%

Extraocular Light Exposure Does Not Phase Shift Saliva Melatonin Rhythms in Sleeping Subjects

et al. 2002

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Preliminary work in humans suggests that extraocular light can shift circadian phase. If confirmed, extraocular light may be of therapeutic benefit in the treatment of circadian-related sleep disorders with the advantage over ocular exposure that it can be administered while subjects are asleep. In sleeping subjects, however, the effect of extraocular light exposure on circadian phase has yet to be fully tested. Likewise, there is limited data on the acute effects of extraocular light on sleep and body temperature that may influence its clinical utility Thirteen subjects [3F, 10M; mean (SD) age = 22.1 (3.0)y] participated in a protocol that totaled 7 nights in the laboratory consisting of a screening phase measurement night followed 1 week later by two counterbalanced experimental sessions each of 3 consecutive nights (habituation, treatment, and posttreatment phase measurement night) separated by 4 days. Saliva was collected for melatonin measurement every half hour from 1800 to 0300 h on the screening night and both the posttreatment phase measurement nights. On the treatment nights, continuous measures of rectal temperature and polysomnographic sleep were collected and overnight urine for measurement of total nocturnal urinary 6-sulphatoxymelatonin excretion. To test for the phase-delaying effects of extraocular light, subjects received either placebo or extraocular light (11,000 lux) behind the right knee from 0100 to 0400 h. Treatment had no significant effect on the onset of saliva melatonin secretion, phase of nocturnal core body temperature, or urinary 6-sulfatoxymelatonin excretion, but a small increase was observed in wakefulness over the light administration period. In summary, extraocular light was not shown to delay circadian phase but was shown to increase wakefulness. The authors suggest that the present protocol has limited application as a treatment for circadian-related sleep disorders.

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