Effects Of Bright Light Treatment Research Articles

Burst firing in Output-Defined Parallel Habenula Circuit Underlies the Antidepressant Effects of Bright Light Treatment.

Research highlights the significance of increased bursting in lateral habenula (LHb) neurons in depression and as a focal point for bright light treatment (BLT). However, the precise spike patterns of LHb neurons projecting to different brain regions during depression, their roles in depression development, and BLT's therapeutic action remain elusive. Here, LHb neurons are found projecting to the dorsal raphe nucleus (DRN), ventral tegmental area (VTA), and median raphe nucleus (MnR) exhibit increased bursting following aversive stimuli exposure, correlating with distinct depressive symptoms. Enhanced bursting in DRN-projecting LHb neurons is pivotal for anhedonia and anxiety, while concurrent bursting in LHb neurons projecting to the DRN, VTA, and MnR is essential for despair. Remarkably, reducing bursting in distinct LHb neuron subpopulations underlies the therapeutic effects of BLT on specific depressive behaviors. These findings provide valuable insights into the mechanisms of depression and the antidepressant action of BLT.

Bright light treatment counteracts stress-induced sleep alterations in mice, via a visual circuit related to the rostromedial tegmental nucleus.

Light in the environment greatly impacts a variety of brain functions, including sleep. Clinical evidence suggests that bright light treatment has a beneficial effect on stress-related diseases. Although stress can alter sleep patterns, the effect of bright light treatment on stress-induced sleep alterations and the underlying mechanism are poorly understood. Here, we show that bright light treatment reduces the increase in nonrapid eye movement (NREM) sleep induced by chronic stress through a di-synaptic visual circuit consisting of the thalamic ventral lateral geniculate nucleus and intergeniculate leaflet (vLGN/IGL), lateral habenula (LHb), and rostromedial tegmental nucleus (RMTg). Specifically, chronic stress causes a marked increase in NREM sleep duration and a complementary decrease in wakefulness time in mice. Specific activation of RMTg-projecting LHb neurons or activation of RMTg neurons receiving direct LHb inputs mimics the effects of chronic stress on sleep patterns, while inhibition of RMTg-projecting LHb neurons or RMTg neurons receiving direct LHb inputs reduces the NREM sleep-promoting effects of chronic stress. Importantly, we demonstrate that bright light treatment reduces the NREM sleep-promoting effects of chronic stress through the vLGN/IGL-LHb-RMTg pathway. Together, our results provide a circuit mechanism underlying the effects of bright light treatment on sleep alterations induced by chronic stress.

A visual circuit related to the habenula mediates the prevention of cocaine relapse by bright light treatment

Despite significant advancements in our understanding of addiction at the neurobiological level, a highly effective extinction procedure for preventing relapse remains elusive. In this study, we report that bright light treatment (BLT) administered during cocaine withdrawal with extinction training prevents cocaine-driven reinstatement by acting through the thalamic-habenular pathway. We found that during cocaine withdrawal, the lateral habenula (LHb) was recruited, and inhibition of the LHb via BLT prevented cocaine-driven reinstatement. We also demonstrated that the effects of BLT were mediated by activating LHb-projecting neurons in the ventral lateral geniculate nucleus and intergeniculate leaflet (vLGN/IGL) or by inhibiting postsynaptic LHb neurons. Furthermore, BLT was found to improve aversive emotional states induced by drug withdrawal. Our findings suggest that BLT administered during the cocaine withdrawal may be a promising strategy for achieving drug abstinence.

A visual circuit related to the periaqueductal gray area for the antinociceptive effects of bright light treatment

Light is a powerful modulator of non-visual functions. Although accumulating evidence suggests an antinociceptive effect of bright light treatment, the precise circuits that mediate the effects of light on nocifensive behaviors remain unclear. Here, we show that bright light treatment suppresses mouse nocifensive behaviors through a visual circuit related to the lateral and ventral lateral parts of the periaqueductal gray area (l/vlPAG). Specifically, a subset of retinal ganglion cells (RGCs) innervates GABAergic neurons in the ventral lateral geniculate nucleus and intergeniculate leaflet (vLGN/IGL), which in turn inhibit GABAergic neurons in the l/vlPAG. The activation of vLGN/IGL-projecting RGCs, activation of l/vlPAG-projecting vLGN/IGL neurons, or inhibition of postsynaptic l/vlPAG neurons is sufficient to suppress nocifensive behaviors. Importantly, we demonstrate that the antinociceptive effects of bright light treatment are dependent on the activation of the retina-vLGN/IGL-l/vlPAG pathway. Together, our results delineate an l/vlPAG-related visual circuit underlying the antinociceptive effects of bright light treatment.

The Effect of Bright Light Treatment on Rest-Activity Rhythms in People with Dementia: A 24-Week Cluster Randomized Controlled Trial.

Bright light treatment is an effective way to influence circadian rhythms in healthy adults, but previous research with dementia patients has yielded mixed results. The present study presents a primary outcome of the DEM.LIGHT trial, a 24-week randomized controlled trial conducted at nursing homes in Bergen, Norway, investigating the effects of a bright light intervention. The intervention consisted of ceiling-mounted LED panels providing varying illuminance and correlated color temperature throughout the day, with a peak of 1000 lx, 6000 K between 10 a.m. and 3 p.m. Activity was recorded using actigraphs at baseline and after 8, 16, and 24 weeks. Non-parametric indicators and extended cosine models were used to investigate rest–activity rhythms, and outcomes were analyzed with multi-level regression models. Sixty-one patients with severe dementia (median MMSE = 4) were included. After 16 weeks, the acrophase was advanced from baseline in the intervention group compared to the control group (B = −1.02, 95%; CI = −2.00, −0.05). There was no significant difference between the groups on any other rest–activity measures. When comparing parametric and non-parametric indicators of rest–activity rhythms, 25 out of 35 comparisons were significantly correlated. The present results indicate that ambient bright light treatment did not improve rest–activity rhythms for people with dementia.

The effects of bright light treatment on affective symptoms in people with dementia: a 24-week cluster randomized controlled trial

BackgroundThe majority of people with dementia have behavioral and psychological symptoms of dementia (BPSD), including depression, anxiety and agitation. These may be elicited or aggravated by disrupted circadian rhythms. Bright light treatment (BLT) is a promising non-pharmacological approach to the management of BPSD, but previous research has yielded mixed results.MethodsEight nursing home dementia units (1 unit = 1 cluster) with 78 patients were invited to participate in a cluster randomized controlled trial from September 2017 to April 2018 investigating the effects of BLT on sleep and circadian rhythms (primary outcome) and BPSD (secondary outcome). Ceiling mounted LED-panels were installed in the intervention group (four units), providing light at 1000 lx and 6000 K (vertically at 1.2 m) between 10 a.m. and 3 p.m., with lower values in the mornings and evenings. Standard indoor light was used in the control group (four units). BPSD were assessed with The Cornell Scale for Depression in Dementia (CSDD) and the Neuropsychiatric Inventory Nursing Home Version (NPI-NH). Data collection took place at baseline and after 8, 16 and 24 weeks. Multilevel regression models with and without false discovery rate correction were used for the analysis, with baseline values and dementia stage entered as covariates.ResultsSixty-nine patients were included in the study at baseline. Compared to the control group, the intervention group had a larger reduction on the composite scores of both the CSDD (95% CI = − 6.0 – − 0.3) and the NPI-NH (95% CI = − 2.2 – − 0.1), as well as on the NPI-NH Affect sub-syndrome, and the CSDD Mood related signs sub-scale at follow-up after 16 weeks. With FDR correction, the group difference was significant on the CSDD Mood related signs sub-scale (95% CI = − 2.7 – − 0.8) and the NPI-NH Affect sub-syndrome (95% CI = − 1.6 – − 0.2). No differences were found between conditions at weeks 8 or 24.ConclusionCompared to the control condition, affective symptoms were reduced after 16 weeks in the group receiving BLT, suggesting BLT may be beneficial for nursing home patients with dementia.Trial registrationClinicalTrials.gov Identifier: NCT03357328. Retrospectively registered on November 29, 2017.

Bright Light Treatment of Combat-related PTSD: A Randomized Controlled Trial.

Post-traumatic stress disorder (PTSD) is a prevalent consequence of combat with significant associated morbidity. Available treatments for PTSD have had limitations, suggesting a need to explore alternative or adjuvant treatments. Numerous rationales for bright light treatment of PTSD include its benefits for common PTSD comorbidities of depression, anxiety, and circadian misalignment and its relative ease of use with few side effects. The primary aims of this research were to examine the effects of bright light treatment for combat-related PTSD and associated morbidity. A randomized controlled trial was performed in N = 69 veterans with PTSD attributable to combat in Afghanistan and/or Iraq. Following a 1-week baseline, participants were randomized to 4 weeks of daily morning bright light treatment (10,000 lux for 30 min/day) or a control treatment (inactivated negative ion generator). At baseline and at the end of treatment, participants were rated blindly on the Clinician Assessed PTSD Scale (CAPS), the Clinical Global Impressions Scale (CGI), and the Hamilton Depression Scale and rated themselves on the PTSD Checklist-Military (PCL-M). Following baseline and each treatment week, participants completed self-reported scales of state anxiety, depression, and sleep, and sleep and the circadian rhythm of wrist activity were also assessed with wrist actigraphy. Compared with the control treatment, bright light elicited significantly greater improvements in the CAPS and CGI-Improvement. The bright light also elicited a significantly greater rate of treatment response (reduction ≥33%) for the CAPS (44.1% vs. 8.6%) and PCL-M (33% vs. 6%), but no participant had remission from PTSD. Changes in depression, anxiety, and sleep did not differ between treatments. Improvement in CAPS was significantly correlated with a phase advance of the circadian rhythm of wrist activity. The most comprehensive study on the topic to date indicated significant short-term efficacy of bright light treatment on the primary variables (CAPS and CGI) with clinical relevance (i.e., treatment response) in veterans with chronic PTSD who did not report extremely high habitual light exposure. No significant effects were found for anxiety, depression, or sleep disturbance. Further research is warranted, particularly exploration of circadian phase-shifting mechanisms of bright light for PTSD.

The effects of bright light treatment via ear canals on quality of sleep and depressive mood among overworked employees: A randomized-controlled clinical trial

Many overworked employees need tools to improve their depressive mood or sleep disorder. In Finland, a new device of bright light therapy was developed. Our objective was to evaluate the effect of bright light treatment via ear canals on improving the depressive mood and sleep disorder. We conducted a randomized, controlled, crossover designed, open-label trial. We examined 27 participants aged 23-52 years, assigned to either Early treatment or Later treatment groups. The Early treatment group used the device on weekdays for the first 4 weeks, followed by a 4-week observation period. The Later treatment group had an observation period for the first 4 weeks, followed by device treatment for the subsequent 4 weeks. Every Friday, the participants were asked to answer questionnaires: A Self-rating Depression Scale (SDS), an Athens Insomnia Scale (AIS), and a Profile of Mood States (POMS) Brief Form. While no significant effect was found on the SDS following treatment (p = 0.16), the AIS showed a significant improvement (p = 0.004), and the scores for the Depression (D) and Vigor (V) of POMs decreased significantly (p = 0.045, p = 0.006, respectively). Bright light treatment via ear canals may improve sleep quality and depressive mood.

0748 A Novel, Non-Pharmacological Treatment Option for Patients With Idiopathic Hypersomnia

Abstract Introduction There is some evidence suggesting that patients with hypersomnia have delayed circadian timing, which could explain, at least in part, the excessive sleepiness and impaired daytime performance experienced by these individuals. This study investigated the effects of bright light treatment on improving daytime alertness in patients with idiopathic hypersomnia. Methods Participants were scheduled to two in-laboratory sessions (baseline and treatment) consisting of overnight sleep monitoring (polysomnography) followed by maintenance of wakefulness tests (MWT) and performance testing (10-min psychomotor vigilance task (PVT)). MWTs were performed at 10:00, 12:00, 14:00 and 16:00 and PVTs were performed at 11:00, 13:00, 15:00 and 15:00. In-laboratory sessions were separated by a two-week at-home treatment period during which participants were instructed to use commercially available light devices for 30-60 min each morning. Participants also completed the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) at baseline and after treatment. Paired t-tests were performed to assess differences in sleep architecture, sleep quality, performance (lapses; reaction time >500ms) and alertness (MWT mean sleep latency) between baseline and treatment. Results To date, three participants (2 male) aged 62.7±13.2 (mean±SD) years have completed the study. Lapses (baseline: 17.9±11.9; treatment: 6.3±5.4), ESS (baseline: 17.3±3.1; treatment 12.3±6.8) and PSQI (baseline: 7.7±3.8; treatment: 4.0±1.0) all improved with light treatment, although this did not reach statistical significance. There were no statistical differences between baseline and treatment with regards to sleep architecture or mean sleep latency. Conclusion Although preliminary, results suggest that bright light treatment may improve subjective sleepiness, subjective sleep quality and performance. There was some variability between individuals, indicating that this treatment may not offer the same benefits to all patients. Although ongoing, this study suggests that light therapy could be used as an alternative, non-pharmacological treatment option to improve waking functions and sleepiness in hypersomnia patients. Support This project is supported by a Hunter Medical Research Institute Research Project Grant

Effect of bright light treatment in patient with post-stroke insomnia

Effect of bright light treatment in patient with post-stroke insomnia

Effects of bright light treatment on psychomotor speed in athletes.

Purpose: A recent study suggests that transcranial brain targeted light treatment via ear canals may have physiological effects on brain function studied by functional magnetic resonance imaging (fMRI) techniques in humans. We tested the hypothesis that bright light treatment could improve psychomotor speed in professional ice hockey players.Methods: Psychomotor speed tests with audio and visual warning signals were administered to a Finnish National Ice Hockey League team before and after 24 days of transcranial bright light or sham treatment. The treatments were given during seasonal darkness in the Oulu region (latitude 65 degrees north) when the strain on the players was also very high (10 matches during 24 days). A daily 12-min dose of bright light or sham (n = 11 for both) treatment was given every morning between 8 and 12 am at home with a transcranial bright light device. Mean reaction time and motor time were analyzed separately for both psychomotor tests. Analysis of variance for repeated measures adjusted for age was performed.Results: Time × group interaction for motor time with a visual warning signal was p = 0.024 after adjustment for age. In Bonferroni post-hoc analysis, motor time with a visual warning signal decreased in the bright light treatment group from 127 ± 43 to 94 ± 26 ms (p = 0.024) but did not change significantly in the sham group 121 ± 23 vs. 110 ± 32 ms (p = 0.308). Reaction time with a visual signal did not change in either group. Reaction or motor time with an audio warning signal did not change in either the treatment or sham group.Conclusion: Psychomotor speed, particularly motor time with a visual warning signal, improves after transcranial bright light treatment in professional ice-hockey players during the competition season in the dark time of the year.

Effects of morning compared with evening bright light administration to ameliorate short-photoperiod induced depression- and anxiety-like behaviors in a diurnal rodent model

The lack of appropriate animal models for affective disorders is a major factor hindering better understanding of the underlying pathologies and the development of more efficacious treatments. Because circadian rhythms play an important role in affective disorders, we recently suggested that diurnal rodents can be advantageous as model animals. We found that in diurnal rodents, short photoperiod induces depression- and anxiety-like behaviors, with similarities to human seasonal affective disorder. In a pilot study we also found that these behaviors are ameliorated by morning bright light administration. In the present study we further evaluated the effects of morning and evening bright light administration on short photoperiod-induced depression- and anxiety-like behaviors in diurnal fat sand rats. Animals were maintained under short (5L:19D) or neutral (12L:12D) photoperiod and treated with morning or evening bright light or red dim light as control. Morning bright light ameliorated the behavioral deficits in the elevated plus maze and social interaction tests whereas evening bright light was effective only in the social interaction test. This is the first detailed presentation of the effects of bright light treatment in an animal model and a clear demonstration to the advantages of utilizing diurnal rodents to study interactions between circadian rhythms and affect.

Improvement in Fatigue, Sleepiness, and Health-Related Quality of Life with Bright Light Treatment in Persons with Seasonal Affective Disorder and Subsyndromal SAD

Objective. To investigate the effects of bright light treatment for secondary outcome measures and to explore and validate empirically derived subgroups and treatment effects in subgroups. Methods. A descriptive design. A sample of forty-nine persons (mean age of 45.8) with clinically assessed seasonal affective disorder (SAD) or subsyndromal SAD (S-SAD) participated in a two-group clinical trial evaluating the effects of treatment with bright light therapy. A person-oriented cluster analysis was applied to study treatment effects in subgroups. Results. For the merged group, sleepiness (Epworth Sleepiness Scale), fatigue (fatigue questionnaire), and health-related quality of life (SF-36) were improved at posttreatment, and results were maintained at the one-month followup. Three distinct subgroups had a high level of fatigue in common, while the level of excessive daytime sleepiness and depressed mood differed between the subgroups. Over time, all subgroups improved following ten days treatment in a light room. Conclusion. Fatigue, excessive daytime sleepiness, and health-related quality of life improve in a similar way as depressed mood following treatment with bright light. The treatment was effective irrespective of the severity of the disorder, that is, for persons with SAD and subsyndromal SAD.

Effects of bright light treatment on depression- and anxiety-like behaviors of diurnal rodents maintained on a short daylight schedule

A possible relationship between circadian rhythms and affective disorders has been strongly implicated, but understanding of the biological basis of such a relationship demands the utilization of appropriate animal models. Most research is performed with nocturnal rodents while some of the effects of daylight cycles or melatonin levels in nocturnal animals may differ greatly from effects in diurnal species (including humans). Recent studies suggested the diurnal fat Sand rat as an appropriate model animal to study circadian mechanisms involvement in mood and anxiety disorders, especially seasonal affective disorder (SAD). These studies demonstrated that Sand rats chronically exposed to short daylight (SD), or to melatonin regimen mimicing short daylight, show anxiety- and depression-like behaviors. These findings established face and construct validity for the model. The present study evaluated predictive validity by testing the effects of bright light treatment in Sand rats exposed to chronic SD. Sand rats maintained on SD for 3 weeks were treated with 1 h daily 3000 lx light for 3 weeks, 1 h after “lights on” (during the light phase of the light/dark cycle), and their behavior tested in the sweet solution preference test (SSP), elevated plus-maze (EPM) and forced swim test (FST) and compared with control animals without treatment. Results indicate that bright light treatment reduced anxiety-like behavior in the EPM and depression-like behavior in the FST but not SSP. It is suggested that the results support the possibility that the diurnal Sand rat might be a preferred model animal for the study of SAD.

Bright Light Treatment Has Limited Effect in Subjects over 55 Years with Mild Early Morning Awakening

31 subjects, age 55 yr. or older, suffering from mild early morning awakening were randomized to either a bright light (10,000 lux) or to a red dim light placebo condition (200 lux). Light exposure took place in the evening in the patients' homes, 60 to 30 min. before bedtime and lasted for 3 wk. The subjects kept a sleep diary for 2 wk. and wore an actigraph for 1 wk. both before treatment and at post-treatment. Of the eight sleep diary outcome variables, significant effects that could be attributed to the light treatment were only detected for time spent in bed after final morning awakening. None of the six actigraph outcome variables yielded any significant effect of the light therapy. Explanations for the limited therapeutic effects of bright light treatment obtained in the present study are discussed, such as the criteria defining early morning awakening, the selection procedure, problems with compliance, age of the sample, and the dose of light. The lack of an objective circadian marker in this study could represent a problem concerning the timing of the light exposure. Despite the limited success of bright light therapy in this study, bright light therapy should still be considered as a treatment option for early morning awakening.

Chromaticity of daylight: is the spectral composition of daylight an aetiological element in winter depression?

Objectives. Surveys on winter depression in Iceland indicate a significantly lower prevalence rate of winter SAD than expected according to Iceland’s latitude. Research into daylight availability in Iceland failed to reveal factors contributing to higher average daylight availability than predicted by latitude. In view of the well-known healing effects of bright light treatment, we propose that properties of daylight other than daylight availability may ease the symptoms of winter depression.Method. We analysed the spectral composition of daylight in Iceland as expressed by its chromaticity and assessed its seasonal and diurnal variations. The colorimetric properties of daylight during the year 1998 are dealt with in detail. Perception of daylight is modelled, applying the chromaticity model of MacLeod and Boynton along with environmental data on spectral irradiance recorded on location at 64°8.8’ N and 21°55.8’ W in Reykjavik, Iceland, and recently published data on cone fundamentals by Stockman and Sharpe.Results. The main finding is that blue hue dominates the colour of the sky, with high correlated colour temperature, without significant seasonal variations. Diurnal variations are, however, observed. Furthermore, significant deviation from ‘standard’ sky is detected.Conclusions. It is not known whether the observed chromaticity of daylight is a significant factor in explaining the unexpectedly low prevalence rate of seasonal affective disorder in Iceland.

Bright light treatment used for adaptation to night work and re-adaptation back to day life. A field study at an oil platform in the North Sea.

Night workers complain of sleepiness, reduced performance and disturbed sleep due to lack of adjustment of the circadian rhythm. In simulated night-work experiments scheduled exposure to bright light has been shown to reduce these complaints. Here we studied the effects of bright light treatment on the adaptation to 14 days of consecutive night work at an oil platform in the North Sea, and the subsequent readaptation to day life at home, using the Karolinska sleep/wake diary. Bright light treatment of 30 min per exposure was applied during the first 4 nights of the night-shift period and the first 4 days at home following the shift period. The bright light exposure was scheduled individually to phase delay the circadian rhythm. Bright light treatment modestly facilitated the subjective adaptation to night work, but the positive effect of bright light was especially pronounced during the re-adaptation back to day life following the return home. Sleepiness was reduced and the quality of day was rated better after exposure to bright light. The modest effect of bright light at the platform was, possibly, related to the finding that the workers seemed to adapt to night work within a few days even without bright light. These results suggest that short-term bright light treatment may help the adaptation to an extended night-work period, and especially the subsequent re-adaptation to day life.

痴呆高齢者に対する高照度光処遇の睡眠への影響

痴呆高齢者に対する高照度光処遇の睡眠への影響

Bright Light: a Countermeasure for Jet Lag?

After time-zone flights, the environmental time is shifted abruptly. The sleep-wake cycle and the circadian system cannot follow this sudden phase shift. Therefore, some or several days are necessary to achieve complete adjustment to a new time zone. The effects resulting from the displacement between internal and external time are well known as jet lag. In principle, timed bright light is able to enhance the resynchronization process of the circadian system after advance or delay shifts. In this report, the effects of bright light exposure on circadian phases and amplitudes after real or simulated time zone transitions are reviewed from the accessible literature and are critically discussed. It can be concluded that laboratory studies have not been unequivocally successful to support the hypothesis that bright light alleviates jet lag. The sparse number of field studies do not yet allow a clear judgment on the beneficial effect of bright light treatment on jet lag. (Chronobiology International, 14(2), 173–183, 1997)

Effect of bright light treatment on agitated behavior in institutionalized elderly subjects

This study examined whether exposure to bright light treatment would reduce agitated behavior in institutionalized elderly subjects. Six demented elderly subjects (mean age = 89.2 years) living in a skilled nursing facility were studied. Light (2500 lx) was administered for 2 hours in the morning for two 10-day periods. The Bliwise Agitation Behavior Rating Scale was used to rate agitated behavior once every 15 min between 16:00 h and 20:00 h during 3 days of baseline, the light treatment periods, and 5 days of posttreatment follow-up evaluation. The entire protocol was then repeated in an ABABA design. A planned comparison revealed a significant difference between light treatment days and nontreatment days, with less agitation being observed on treatment days. The study suggests the efficacy of the clinical use of bright light treatment to reduce agitation.