Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

Health

The Part of the Brain That Lets the Blind See Without Seeing

80beatsBy Andrew MosemanJune 24, 2010 6:28 PM
blind.jpg

Newsletter

Sign up for our email newsletter for the latest science news

The weird phenomenon of blindsight—in which people take in visual information about objects without actually "seeing" them—has long intrigued scientists, and with good reason. They've watched people navigate obstacle courses and identify colors while being technically blind. This week, in a study in Nature, neuroscientists point to a part of the brain called the lateral geniculate nucleus (LGN) as the neural key that might make blindsight possible.

They used macaques in which the primary visual cortex had been destroyed. The monkeys' eye-focusing movements revealed that they were "seeing" images shown at the periphery of their visual field, but only if their LGN was intact [New Scientist].

The authors refer to the LGN as the "main relay" between the retina and main visual cortex.

Other work had shown that the LGN also has projections to a number of secondary visual areas, suggesting that it may serve as a major hub in the visual system. To test this suggestion, the authors injected the LGN with a chemical that activates the receptor for a major inhibitory signaling molecule.... When the chemical is present, nerve cells receive a signal telling them to stop signaling, so this this injection has the effect of shutting the LGN down entirely [Ars Technica].

When the scientists shut down the LGN, the primates in the study didn't experience any blindsight, as it appears no information was reaching any of their brains' visual centers. Related Content: DISCOVER: What You See Is What You Don't

80beats: Blind Man Navigates an Obstacle Course Using Only "Blindsight"

80beats: By Developing "Blindsight," Stroke Patients Can See—And Drive—Again

Image: iStockphoto

2 Free Articles Left

Want it all? Get unlimited access when you subscribe.

Subscribe

Already a subscriber? Register or Log In

Want unlimited access?

Subscribe today and save 70%

Subscribe

Already a subscriber? Register or Log In