CHICAGO, May 2 (Xinhua) -- A research led by Northwestern University (NU) has found that a subset of retinal neurons sends inhibitory signals to the brain, besides excitatory signals.
To conduct the study, the researchers blocked the retinal neurons responsible for inhibitory signaling in a mouse model. When this signal was blocked, dim light was more effective at shifting the mice's circadian rhythms.
"This suggests that there is a signal from the eye that actively inhibits circadian rhythms realignment when environmental light changes, which was unexpected," said NU's Tiffany Schmidt, an assistant professor of neurobiology at NU's Weinberg College of Arts and Sciences.
The researchers also found that, when the inhibitory signals from the eye were blocked, mice's pupils were much more sensitive to light.
"These inhibitory signals prevent our circadian clock from resetting to dim light and prevent pupil constriction in low light, both of which are adaptive for proper vision and daily function," said Schmidt. "We think that our results provide a mechanism for understanding why our eye is so exquisitely sensitive to light, but our subconscious behaviors are comparatively insensitive to light."
The research was published Friday in the journal Science. Enditem
