A recent study investigating the role of melanopsin in non-image forming functions found that targeted destruction of melanopsin cells had no impact on the light:dark preference of mice [18].
Animals were assessed in the open field, accelerating rotarod, light and dark preference, and nest-building tests as previously described (34, 39).
We believe that the lack of these cues makes the cLDB a better instrument to measure light avoidance or dark preference than the light-dark boxes normally used in rodent studies (see also [ 94]).
Finally, an analysis of visual competency through the use of the visual cliff and light-dark preference tasks indicates that conjugate-injected animals do not suffer any gross defects in visual perception.
Unexpectedly, our light-dark preference test, which is unlikely to involve either image formation or optomotor reflexes, was performed equally well by both sighted and melanopsin cell deficient mice, implying that this is behavior relies on different neural mechanisms than used for simple irradiance detection (cf., [31].
In general, light-dark preference tests are based on the observation that, given the choice, a rat 'prefers' to stay in the unlit rather than lit part of a test environment.
Several tests are available to assess unconditioned emotional reactivity, fear or anxiety, in rodents [ 2, 13], such as the open field, the light-dark preference box, and the elevated plus maze.
The performance of male Brown Norway, Lewis, Fischer 344, and Wistar Kyoto rats in open field (OF), elevated plus-maze (EPM), and circular light-dark preference box (cLDB) tasks, which are believed to provide measures of emotional reactivity, was evaluated.
The c ircular l ight- d ark preference B ox (cLDB) is our variant of the light-dark preference box [ 14, 21, 30, 31] designed to assess the effects of experimental manipulations on emotional reactivity in rats.
We designed a circular Light-Dark preference Box (cLDB) [ 12] that, apart from differences in light intensity, lacks any spatial cues for the light compartment and the dark compartment and has a sharp transition from the light to the dark compartments.
At the population level, SLAG vision assessment can be validated by a second assay that is based on a different innate response, Dark Chamber preference.
