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:12/10/2016)... ... December 10, 2016 , ... When faced with having to use a toilet ... seat to her body, and contamination of children when they use public toilets. This ... problem that many people face. , The patent-pending SANI-POCKET enables a person to use ...
(Date:12/9/2016)... ... December 09, 2016 , ... Flottman Company is ... As a means of expanding capabilities Flottman has added a G&K Vijuk ... code professional inserts (PIs) and patient package inserts (PPIs) that will marry with ...
(Date:12/9/2016)... ... December 09, 2016 , ... An inventor from Cana, Va., wanted to ... types of amusement park rides. , The patent-pending SAFETY STRAP FOR AMPUTEES improves accessibility. ... and could be set up in a matter of minutes, or even seconds. The ...
(Date:12/9/2016)... ... December 09, 2016 , ... "I had a terrible time trying to ... "I thought that if the nebulizer had a more child-friendly design, then children would ... He developed the patent-pending NEBY to avoid the need to deliver medication via a ...
(Date:12/8/2016)... ... 08, 2016 , ... After enjoying record-breaking attendance at its ... its 33rd Annual Issues & Research Conference, March 2-3, 2017, at the ... conference is “Persistent Challenges and New Opportunities: Using Research to Accelerate the Dialogue." ...
Breaking Medicine News(10 mins):
(Date:12/9/2016)... Research and Markets has announced the addition ... their offering. ... The global travel vaccines market to grow at a CAGR of ... present scenario and the growth prospects of the global travel vaccines ... the revenue generated from the sales of various vaccines administered to ...
(Date:12/8/2016)... Dec. 8, 2016 Australia Ophthalmic Lasers Market ... "Australia Ophthalmic Lasers Market Outlook to 2022", provides key ... report provides value, in millions of US dollars, volume ... - Excimer Lasers, Femtosecond Lasers and YAG Lasers. ... data for each of these market segements, and global ...
(Date:12/8/2016)... 8, 2016 KEY FINDINGS The ... in 2017-2023. Various reasons for growth of the medical ... incidences of chronic diseases, high recovery cost of injuries ... Medical lifting sling refers to an assistive device ... These slings connect to the lift and hold the ...
Breaking Medicine Technology: