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:5/27/2016)... ... May 27, 2016 , ... Two director-level employees of ... Tribute to Women and Industry (TWIN) 2016 honorees. The award recognizes businesswomen who ... this year, Geri Boone, Director of the MLTSS (Managed Long-Term Services and Supports) Program ...
(Date:5/27/2016)... ... 27, 2016 , ... This campaign aims to provide a path to improved ... can control and change. , As nearly 795,000 Americans suffering from a new or ... States. Plus, with an estimated 129,000 of these people dying from stroke, it’s become ...
(Date:5/27/2016)... ... May 27, 2016 , ... Aimed at nurses ... human interest stories, courtesy of leaders in the nursing and health care industry. ... from leading advocates and associations—namely Jones & Bartlett Learning. , Jones & Bartlett ...
(Date:5/26/2016)... (PRWEB) , ... May 26, 2016 , ... Despite last ... meeting, expect Janet Yellen and company to wait until March 2017 for an interest ... University’s J. Mack Robinson College of Business. , “The Federal Open Market Committee (FOMC) ...
(Date:5/26/2016)... ... May 26, 2016 , ... ... hosted members and suppliers for its inaugural Member Conference at the Paris Hotel ... of elevating the operational health of America’s healthcare providers. , The conference was ...
Breaking Medicine News(10 mins):
(Date:5/26/2016)... A key trend that will ... of new treatments. Cardax, a development stage life sciences ... therapy is expected to fulfil large unmet medical needs ... studies to develop new treatments for osteoarthritis. One such ... in osteoarthritis are being investigated, and early trials of ...
(Date:5/25/2016)... FDA 510(k) clearance covers Confocal Miniprobes ... and surgical applications Mauna Kea Technologies ... multidisciplinary confocal laser endomicroscopy (CLE) platform, today announced ... the 12 th 510(k) clearance from United ... FDA clearance covers Confocal Miniprobes indicated for use ...
(Date:5/25/2016)...  Zymo Research Corp. announced today the final ... that help researchers obtain the most accurate and ... rapid growth of the study of microbiomes has ... methods to improve the reproducibility and quality of ... every step of the measurement process including collection ...
Breaking Medicine Technology: