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Relative importance of intensity and spectrum of artificial light at night in disrupting behavior of a nocturnal rodent

Cite this dataset

Longcore, Travis et al. (2024). Relative importance of intensity and spectrum of artificial light at night in disrupting behavior of a nocturnal rodent [Dataset]. Dryad. https://doi.org/10.5061/dryad.t1g1jwtb0

Abstract

The influence of light spectral properties on circadian rhythms is of substantial interest to laboratory-based investigation of the circadian system and to field-based understanding of the effects of artificial light at night. The tradeoffs between intensity and spectrum regarding masking behaviors are largely unknown, even for well-studied organisms. We used a custom LED illumination system to document the response of wild type house mice (Mus musculus) to 1-hr nocturnal exposure of all combinations of four intensity levels (0.01, 0.5, 5, and 50 lx) and three correlated color temperatures (CCT; 1750, 1950, and 3000 K). Higher intensities of light (50 lx) suppressed cage activity substantially, and consistently more for the higher CCT light (91% for 3000 K; 53% for 1750 K). At the lower intensities (0.01 lx), mean activity was increased, with the greatest increases for the lowest CCT (12.3% increase at 1750 K; 3% increase at 3000 K). Multiple linear regression confirmed the influence of both CCT (p&lt;0.001) and intensity (p&lt;0.001) on changes in activity (r2=0.66, F9,171=3.33; p<0.001) with the scaled effect size of intensity 3.6 times greater than CCT. Activity suppression was significantly lower for male than female mice (p&lt;0.0001). Assessment of light-evoked cFos expression in the suprachiasmatic nucleus at 50 lx showed no significant difference between high and low CCT exposure. The significant differences by spectral composition illustrate a need to account for light spectrum in circadian studies of behavior and confirm that spectral controls can mitigate some, but certainly not all, of the effects of light pollution on species in the wild.

README: Relative importance of intensity and spectrum of artificial light at night in disrupting behavior of a nocturnal rodent

https://doi.org/10.5061/dryad.t1g1jwtb0

Three datasets: 1. Change in activity (suppression) at night from a 1 hr exposure of light at three different correlated color temperatures (CCT) and four different intensities (measured in lx). 2. Number of cFos+ cells at two CCTs after a 50 lx exposure. 3. Spectral power distribution of the experimental lamps at different CCTs

Description of the data and file structure

There are three csv files containing the three datasets.

SuppressionDataset.csv

Intensity (lx) -- brightness of the light measured at the bottom of the enclosure in lux (human-weighted irradiance).

CCT -- correlated color temperature of the light source

sex - male (M) or female (F)

Mouse Number - unique identifier for each mouse

Suppression - degree to which activity decreased (positive numbers) or increased (negative numbers) , ranges -1 to 1

cFosdata.csv

CCT - correlated color temperature of experimental lamp (see SPD.csv for spectral power distribution)

Number cFos+ Cells -- number of cFos positive cells observed

SPD.csv

wavelength - bins of 1-nm wavelengths in nanometers

SPD - power emitted within 1-nm band

Lamp -- name of lamp (Ecosense 1750 K, Ecosense 1950 K, and Ecosense 3000 K)

Funding

California Department of Transportation, Award: #65A0766