Neuronal Responses to Short Wavelength Light Deficiency in the Rat Subcortical Visual System

The amount and spectral composition of light changes considerably during the day, with dawn and dusk being the most crucial moments when light is within the mesopic range and short wavelength enriched. It was recently shown that animals use both cues to adjust their internal circadian clock, thereby their behavior and physiology, with the solar cycle. The role of blue light in circadian processes and neuronal responses is well established, however, an unanswered question remains: how do changes in the spectral composition of light (short wavelengths blocking) influence neuronal activity? In this study we addressed this question by performing electrophysiological recordings in image (dorsal lateral geniculate nucleus; dLGN) and non-image (the olivary pretectal nucleus; OPN, the suprachiasmatic nucleus; SCN) visual structures to determine neuronal responses to spectrally varied light stimuli. We found that removing short-wavelength from the polychromatic light (cut off at 525 nm) attenuates the most transient ON and sustained cells in the dLGN and OPN, respectively. Moreover, we compared the ability of different types of sustained OPN neurons (either changing or not their response profile to filtered polychromatic light) to irradiance coding, and show that both groups achieve it with equal efficacy. On the other hand, even very dim monochromatic UV light (360 nm; log 9.95 photons/cm2/s) evokes neuronal responses in the dLGN and SCN. To our knowledge, this is the first electrophysiological experiment supporting previous behavioral findings showing visual and circadian functions disruptions under short wavelength blocking environment. The current results confirm that neuronal activity in response to polychromatic light in retinorecipient structures is affected by removing short wavelengths, however, with type and structure – specific action. Moreover, they show that rats are sensitive to even very dim UV light.

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Multiple Phototransduction Inputs Integrate to Mediate UV Light–evoked Avoidance/Attraction Behavior in Drosophila

Journal of Biological Rhythms ◽

10.1177/0748730419847339 ◽

2019 ◽

Vol 34 (4) ◽

pp. 391-400 ◽

Cited By ~ 7

Author(s):

Lisa Soyeon Baik ◽

Yocelyn Recinos ◽

Joshua A. Chevez ◽

David D. Au ◽

Todd C. Holmes

Keyword(s):

Short Wavelength ◽

Uv Light ◽

Behavioral Responses ◽

Time Of Day ◽

Spatiotemporal Resolution ◽

Circadian Time ◽

Light Duration ◽

Short Wavelength Light ◽

Attraction Behavior ◽

Wavelength Light

Short-wavelength light guides many behaviors that are crucial for an insect’s survival. In Drosophila melanogaster, short-wavelength light induces both attraction and avoidance behaviors. How light cues evoke two opposite valences of behavioral responses remains unclear. Here, we comprehensively examine the effects of (1) light intensity, (2) timing of light (duration of exposure, circadian time of day), and (3) phototransduction mechanisms processing light information that determine avoidance versus attraction behavior assayed at high spatiotemporal resolution in Drosophila. External opsin-based photoreceptors signal for attraction behavior in response to low-intensity ultraviolet (UV) light. In contrast, the cell-autonomous neuronal photoreceptors, CRYPTOCHROME (CRY) and RHODOPSIN 7 (RH7), signal avoidance responses to high-intensity UV light. In addition to binary attraction versus avoidance behavioral responses to UV light, flies show distinct clock-dependent spatial preference within a light environment coded by different light input channels.

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Alerting and Circadian Effects of Short-Wavelength vs. Long-Wavelength Narrow-Bandwidth Light during a Simulated Night Shift

Clocks & Sleep ◽

10.3390/clockssleep2040037 ◽

2020 ◽

Vol 2 (4) ◽

pp. 502-522

Author(s):

Erlend Sunde ◽

Torhild Pedersen ◽

Jelena Mrdalj ◽

Eirunn Thun ◽

Janne Grønli ◽

...

Keyword(s):

Task Performance ◽

Short Wavelength ◽

Night Shift ◽

Spectral Composition ◽

Photon Density ◽

Light Conditions ◽

Long Wavelength ◽

Narrow Bandwidth ◽

Short Wavelength Light ◽

Wavelength Light

Light can be used to facilitate alertness, task performance and circadian adaptation during night work. Novel strategies for illumination of workplaces, using ceiling mounted LED-luminaires, allow the use of a range of different light conditions, altering intensity and spectral composition. This study (ClinicalTrials.gov Identifier NCT03203538) investigated the effects of short-wavelength narrow-bandwidth light (λmax = 455 nm) compared to long-wavelength narrow-bandwidth light (λmax = 625 nm), with similar photon density (~2.8 × 1014 photons/cm2/s) across light conditions, during a simulated night shift (23:00–06:45 h) when conducting cognitive performance tasks. Light conditions were administered by ceiling mounted LED-luminaires. Using a within-subjects repeated measurements study design, a total of 34 healthy young adults (27 females and 7 males; mean age = 21.6 years, SD = 2.0 years) participated. The results revealed significantly reduced sleepiness and improved task performance during the night shift with short-wavelength light compared to long-wavelength light. There was also a larger shift of the melatonin rhythm (phase delay) after working a night shift in short-wavelength light compared to long-wavelength light. Participants’ visual comfort was rated as better in the short-wavelength light than the long-wavelength light. Ceiling mounted LED-luminaires may be feasible to use in real workplaces, as these have the potential to provide light conditions that are favorable for alertness and performance among night workers.

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Distinct contribution of cone photoreceptor subtypes to the mammalian biological clock

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2024500118 ◽

2021 ◽

Vol 118 (22) ◽

pp. e2024500118

Author(s):

Hester C. van Diepen ◽

Robin A. Schoonderwoerd ◽

Ashna Ramkisoensing ◽

Jan A. M. Janse ◽

Samer Hattar ◽

...

Keyword(s):

Neuronal Activity ◽

Uv Light ◽

Biological Clock ◽

Green Light ◽

Sustained Response ◽

Activity Levels ◽

Cone Photoreceptors ◽

Light Levels ◽

Electrophysiological Recordings

Ambient light detection is important for the synchronization of the circadian clock to the external solar cycle. Light signals are sent to the suprachiasmatic nuclei (SCN), the site of the major circadian pacemaker. It has been assumed that cone photoreceptors contribute minimally to synchronization. Here, however, we find that cone photoreceptors are sufficient for mediating entrainment and transmitting photic information to the SCN, as evaluated in mice that have only cones as functional photoreceptors. Using in vivo electrophysiological recordings in the SCN of freely moving cone-only mice, we observed light responses in SCN neuronal activity in response to 60-s pulses of both ultraviolet (UV) (λmax 365 nm) and green (λmax 505 nm) light. Higher irradiances of UV light led to irradiance-dependent enhancements in SCN neuronal activity, whereas higher irradiances of green light led to a reduction in the sustained response with only the transient response remaining. Responses in SCN neuronal activity decayed with a half-max time of ∼9 min for UV light and less than a minute for green light, indicating differential input between short-wavelength–sensitive and mid-wavelength–sensitive cones for the SCN responsiveness. Furthermore, we show that UV light is more effective for photoentrainment than green light. Based on the lack of a full sustained response in cone-only mice, we confirmed that rapidly alternating light levels, rather than slowly alternating light, caused substantial phase shifts. Together, our data provide strong evidence that cone types contribute to photoentrainment and differentially affect the electrical activity levels of the SCN.

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Effects of reduced nocturnal phone light exposure on sleep – A comparison of the decreased polychromatic light and the blocked short wavelength light conditions

IBRO Reports ◽

10.1016/j.ibror.2019.07.422 ◽

2019 ◽

Vol 6 ◽

pp. S132-S133

Author(s):

Chuan Li ◽

Ming Yi Choi ◽

Augustine Li ◽

Chun Lok Wu ◽

Zenab Bibi

Keyword(s):

Short Wavelength ◽

Light Exposure ◽

Light Conditions ◽

Polychromatic Light ◽

Short Wavelength Light ◽

Wavelength Light

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Does the brain care about averages? A simple test.

10.1101/2021.11.28.469673 ◽

2021 ◽

Author(s):

Alejandro Tlaie ◽

Katharine A Shapcott ◽

Paul Tiesinga ◽

Marieke Schölvinck ◽

Martha N Havenith

Keyword(s):

Neuronal Activity ◽

Simple Test ◽

Average Response ◽

Neuronal Responses ◽

Single Trial ◽

Data Set ◽

Tuning Curves ◽

Cortical Areas ◽

Electrophysiological Recordings ◽

Neuronal Computation

Trial-averaged metrics, e.g. in the form of tuning curves and population response vectors, are a basic and widely accepted way of characterizing neuronal activity. But how relevant are such trial-averaged responses to neuronal computation itself? Here we present a simple test to estimate whether average responses reflect aspects of neuronal activity that contribute to neuronal processing in a specific context. The test probes two assumptions inherent in the usage of average neuronal metrics: 1) Reliability: Neuronal responses repeat consistently enough across single stimulus instances that the average response template they relate to remains recognizable to downstream regions. 2) Behavioural relevance: If a single-trial response is more similar to the average template, this should make it easier for the animal to identify the correct stimulus or action. We apply this test to a large publicly available data set featuring electrophysiological recordings from 42 cortical areas in behaving mice. In this data set, we show that single-trial responses were less correlated to the average response template than one would expect if they simply represented discrete versions of the template, down-sampled to a finite number of spikes. Moreover, single-trial responses were barely stimulus-specific — they could not be clearly assigned to the average response template of one stimulus. Most importantly, better-matched single-trial responses did not predict accurate behaviour for any of the recorded cortical areas. We conclude that in this data set, average responses do not seem particularly relevant to neuronal computation in a majority of brain areas, and we encourage other researchers to apply similar tests when using trial-averaged neuronal metrics.

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Spectral information as an orientation cue in dung beetles

Biology Letters ◽

10.1098/rsbl.2015.0656 ◽

2015 ◽

Vol 11 (11) ◽

pp. 20150656 ◽

Cited By ~ 23

Author(s):

Basil el Jundi ◽

James J. Foster ◽

Marcus J. Byrne ◽

Emily Baird ◽

Marie Dacke

Keyword(s):

Short Wavelength ◽

Uv Light ◽

Green Light ◽

Dung Beetles ◽

Spectral Information ◽

Spectral Cues ◽

Ball Rolling ◽

Short Wavelength Light ◽

Wavelength Light ◽

Colour Gradient

During the day, a non-uniform distribution of long and short wavelength light generates a colour gradient across the sky. This gradient could be used as a compass cue, particularly by animals such as dung beetles that rely primarily on celestial cues for orientation. Here, we tested if dung beetles can use spectral cues for orientation by presenting them with monochromatic (green and UV) light spots in an indoor arena. Beetles kept their original bearing when presented with a single light cue, green or UV, or when presented with both light cues set 180° apart. When either the UV or the green light was turned off after the beetles had set their bearing in the presence of both cues, they were still able to maintain their original bearing to the remaining light. However, if the beetles were presented with two identical green light spots set 180° apart, their ability to maintain their original bearing was impaired. In summary, our data show that ball-rolling beetles could potentially use the celestial chromatic gradient as a reference for orientation.

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