Navigation Links
Out of sight, out of mind? Not necessarily

Visual information can be processed unconsciously when the area of the brain that records what the eye sees is temporarily shut down, according to research at Rice University in Houston.

The research, published the week of Oct. 31 in the Proceedings of the National Academy of Sciences' (PNAS) online Early Edition, suggests the brain has more than one pathway along which visual information can be sent.

For the study, the researchers induced temporary, reversible blindness lasting only a fraction of a second in nine volunteers with normal vision. Transcranial magnetic stimulation (TMS), a harmless noninvasive technique using brief magnetic pulses, was applied to the volunteers' visual cortex -- the area at the back of the brain that processes what the eye sees - to interrupt the normal visual pathway. The volunteers looked at a computer screen, and during their momentary blindness, either a horizontal or a vertical line or a red or a green dot flashed on the screen.

Researchers then asked the study participants whether they had seen a horizontal or a vertical line; because their primary visual pathway had been shut down, the participants reported that they saw nothing. However, when forced to guess which line had appeared on their computer screen, the participants gave the correct answer 75 percent of the time. When the participants had to guess whether a red or a green dot had flashed on the screen, they gave the correct answer with 81 percent accuracy.

"This high degree of accuracy for both the directional orientation and color tasks was significantly above chance," said Tony Ro, associate professor of psychology and principal investigator for the study. "Even though the human primary visual cortex activity was temporarily shut down, it's clear that detailed visual information was still being processed unconsciously."

Because only a certain region of the thalamus - the area of the brain where all sensory information is rela yed -- can process color, the study provides evidence that there must be a pathway that goes through this region of the thalamus to the higher visual centers of the brain, Ro said.

"In addition to providing direct evidence that unconscious processing takes place within the brain - a controversial claim that was advanced by the likes of Sigmund Freud and William James - our results suggest that multiple pathways relay visual input into the central nervous system for different types of processing," Ro said. "And our study also begins to shed light on the brain structures that are necessary for consciousness, with the primary visual cortex playing an essential role for visual awareness."

The phenomenon of "blindsight" has been reported in patients with brain damage who report not seeing something but correctly identify the shape and location when forced to guess. Ro noted that his study demonstrates that TMS can be used successfully to induce blindsight in people with normal vision.

Ro's co-authors on the PNAS paper were graduate student Jennifer Boyer and Stephanie Harrison, a summer intern.


'"/>

Source:Rice University


Related biology news :

1. An artificial cornea is in sight, thanks to biomimetic hydrogels
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/20/2017)... ALLENTOWN, Pa. , March 20, 2017 ... PD 2.0 personal spirometer and Wellness Management System (WMS), ... Founded in 2010, PMD Healthcare is a ... Company with a mission dedicated to creating innovative solutions ... of life. With that intent focus, PMD developed the ...
(Date:3/9/2017)... , Australia , March 9, ... study data at the prestigious World Lung Imaging Workshop ... Andreas Fouras , was invited to deliver the ... pulmonary medicine. This globally recognised event brings together leaders ... share the latest developments in lung imaging. ...
(Date:3/7/2017)... 2017   HireVue , the leading provider of ... the best talent, faster, today announced the additions of ... and Diana Kucer as Chief Marketing Officer ... team poised to drive continued growth in the company,s ... of record bookings in 2017. "Companies worldwide ...
Breaking Biology News(10 mins):
(Date:4/25/2017)... California (PRWEB) , ... April 25, 2017 , ... ... Analytical Services and Metrology Partners.     , Covalent’s Analytical Services unit provides ... samples can be measured within 24 hours of receipt. There are no price ...
(Date:4/24/2017)... , April 24, 2017  Dante Labs announced today the ... EUR 850 (ca. $900). While American individuals have been able ... time Europeans can access WGS below EUR 1,000. ... to leveraging genetic information to make informed decisions about disease ... ...
(Date:4/21/2017)... ... April 21, 2017 , ... ... Bank, today announced first round funding to three startups through the UConn Innovation ... support to new business startups affiliated with UConn. , The UConn Innovation Fund ...
(Date:4/21/2017)... ... April 21, 2017 , ... Frederick Innovative Technology ... of emerging bio and technology start-ups, is hosting “Celebration Friday” (a festive gathering ... will start with libations and networking at 3:30 p.m. at FITCI’s 4539 Metropolitan ...
Breaking Biology Technology: