PROVIDENCE, R.I. [Brown University] Any parent knows that newborns still have a lot of neurological work to do to attain fully acute vision. In a wide variety of nascent animals, genes provide them with only a rough wiring plan and then leave it to the developing nervous system to do its own finish work. Two studies by Brown University researchers provide new evidence of a role for exposure to light in the environment as mouse pups and tadpoles organize and refine the circuitry of their vision systems.
"Through a combination of light-independent and light-dependent processes, the visual system is getting tuned up over time," said David Berson, professor of neuroscience.
His new work, published in advance online June 5 in Nature Neuroscience, offers the surprising result that light exposure can enhance how well mice can organize the nerve endings from their left eye and their right eye in an area of the brain where they start out somewhat jumbled. Neuroscientists had thought that mammals were unable to see at this stage, but a new type of light-sensitive cell that Berson discovered a decade ago turns out to let in the light.
Meanwhile, Berson's colleague Carlos Aizenman, assistant professor of neuroscience, co-authored a paper online May 31 in the Journal of Neuroscience showing that newborn tadpoles depend on light to coordinate and improve the response speed, strength and reliability of a network of neurons in a vision-processing region of their brains.
"This is how activity is allowing visual circuits to refine and sort themselves out," said Aizenman. "Activity is fine-tuning all these connections. It's making the circuit function in a much more efficient, synchronous way."
Not completely blind mice
Berson, postdoctoral scholar Jordan Renna, and former postdoctoral researcher Shijun Weng conducted several experiments in newborn mice to see whether light influences the process by which the mi
|Contact: David Orenstein|