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TUESDAY, Dec. 3, 2019 (HealthDay News) -- Though fetuses spend nine months in a dark womb, they may detect light by the second trimester, a new study in mice suggests.
That's when light-sensing cells develop in the retina, and it may set up the day-night rhythms that the infant will follow, the researchers said.
These cells talk with each other and the brain, giving the retina greater light sensitivity than once believed. These connections may enhance behavior and brain development, the findings suggest.
Besides fine-tuning the internal clock's day-night cycle, the interaction of these cells and the brain may also make pupils constrict in bright light.
Some of these retina cells also connect the perihabenula, which regulates mood, and the amygdala, which deals with emotions, the researchers noted.
"Given the variety of these ganglion cells and that they project to many different parts of the brain, it makes me wonder whether they play a role in how the retina connects up to the brain," said researcher Marla Feller, a University of California, Berkeley, professor of molecular and cell biology.
"Maybe not for visual circuits, but for non-vision behaviors. Not only the pupillary light reflex and circadian rhythms, but possibly explaining problems like light-induced migraines, or why light therapy works for depression," she said in a university news release.
The report was published online recently in the journal Current Biology. Not all animal research translates into humans.
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