Navigation Links
To see or not to see
Date:1/14/2010

How do the visual images we experience, which have no tangible existence, arise out of physical processes in the brain? New research at the Weizmann Institute of Science provided evidence, for the first time, that an 'ignition' of intense neural activity underlies the experience of seeing.

In research recently published in the journal Neuron, Prof. Rafael Malach and research student Lior Fisch of the Weizmann Institute's Neurobiology Department worked with a neurosurgeon, Dr. Itzhak Fried of Tel Aviv Sourasky Medical Center, a distinguished team of medical doctors from the Center and Weizmann Institute students. They asked a group of epileptic patients who had had electrodes clinically implanted into their brains in preparation for surgery to volunteer for some perceptual awareness tasks. The subjects looked at a computer screen, which briefly presented a 'target' image a face, house, or man-made object. This image was followed by a 'mask' a meaningless picture for distraction at different time intervals after the target image had been presented. This allowed the experimenter to control the visibility of the images the patients sometimes recognized the targets and sometimes failed to do so. By comparing the electrode recordings to the patients' reports of whether they had correctly recognized the image or not, the scientists were able to pinpoint when, where and what was happening in the brain as transitions in perceptual awareness took place.

Malach: 'We found that there was a rapid burst of neural activity occurring in the high-order visual centers of the brain centers that are sensitive to entire images of objects, such as faces whenever patients had correctly recognized the target image.' The scientists also found that the transition from not seeing to seeing happens abruptly. Fisch: 'When the mask was presented too soon after the target image, it 'killed' the visual input signals, resulting in the patients being unable to recognize the object. The patients suddenly became consciously aware of the target image at a clear threshold, suggesting that the brain needs a specific amount of time to process the input signals in order for conscious perceptual awareness to be 'ignited.''

This study is the first of its kind to uncover strong evidence linking 'ignition' of bursts of neural activity to perceptual awareness in humans. More questions remain: Is this the sole mechanism involved in the transition to perceptual awareness? To what extent is it a local phenomenon? By answering such questions, we might begin bridging the mysterious gap between mind and the brain.


'/>"/>

Contact: Yivsam Azgad
news@weizmann.ac.il
972-893-43856
Weizmann Institute of Science
Source:Eurekalert

Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/3/2016)... ... ... Elizabeth Murray has always loved walking one to two miles a day. She ... one on her arm. But she got to the point where she could barely ... The valves of the heart wouldn’t close properly resulting in mitral regurgitation, where blood ...
(Date:5/3/2016)... ... 2016 , ... Empyrean Benefit Solutions, Inc., the Hi-Touch Benefits ... in La Vergne, Tennessee, near Nashville. The new center will complement Empyrean’s existing ... services. , “Our Nashville-area center allows us to achieve several goals,” said Richard ...
(Date:5/3/2016)... ... 2016 , ... Ogawa World USA introduced the first of its kind ... Smart Application. The Smart 3D combines the best in technological advancement, design, and massage ... and specialized massage program, each user has a tailored experience unparalleled by any other ...
(Date:5/3/2016)... ... , ... Dr. Poneh Ghasri, cosmetic dentist in West Hollywood , is ... patients. Cosmetic dentistry allows patients to improve the aesthetics of their smiles. These treatments ... or more serious cosmetic flaws. These specials allow patients to achieve their dream smiles ...
(Date:5/3/2016)... ... ... Finding the right way to address a patient’s condition before it worsens will ultimately lower ... , “You do the right thing, at the right time, at the right dose with ... Leonard M. Fromer, MD, FAAFP, from Group Practice Forum. “Even if the cost of the ...
Breaking Medicine News(10 mins):
(Date:5/2/2016)... , May 2, 2016 Kalorama Information noted ... Medical Records) market in a recent white paper.  The ... Increased physician usage, a growing market are among the ... in Kalorama,s report EMR 2016: The Market ... Kalorama,s seventh complete study of the EMR industry, and ...
(Date:5/2/2016)... , May 2, 2016  Celsion Corporation (NASDAQ: ... today announced data from the first cohort of ... trial (the OVATION Study) combining GEN-1, the Company,s ... the treatment of newly-diagnosed patients with advanced ovarian ... interval debulking surgery.  In the first three patients ...
(Date:4/29/2016)... , April 29, 2016 ... for Life Sciences, Product Development Capabilities in ... Science Customer Base . Indegene ... today announced the acquisition of Skura Corporation,s life ... leader in adaptive sales enablement technology for life ...
Breaking Medicine Technology: