Thresholds for masking responses to light in three strains of retinally degenerate mice

N Mrosovsky, RG Foster, PA Salmon - Journal of Comparative Physiology …, 1999 - Springer
N Mrosovsky, RG Foster, PA Salmon
Journal of Comparative Physiology A, 1999Springer
Mutant mice with retinal degeneration (rd/rd) were given 1-h pulses of light of varying
brightness at times of the night when they would normally be active. The mutant mice
showed a significantly greater inhibition of locomotor activity to light (negative masking) than
wildtype controls. Lack of impairment, or even enhancement of negative masking suggests
that this response may depend on sparing in retinally degenerate mice of the same receptor
type that mediates clock resetting, because synchronization of the circadian system is known …
Abstract
Mutant mice with retinal degeneration (rd/rd) were given 1-h pulses of light of varying brightness at times of the night when they would normally be active. The mutant mice showed a significantly greater inhibition of locomotor activity to light (negative masking) than wildtype controls. Lack of impairment, or even enhancement of negative masking suggests that this response may depend on sparing in retinally degenerate mice of the same receptor type that mediates clock resetting, because synchronization of the circadian system is known to be unimpaired in these mutants. With very dim light pulses, mutants did not change their activity, but wildtypes actually became more active (positive masking). Positive and negative masking appear to depend on different sensory and central processes.
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