Navigation Links
Wired for sound: How the brain senses visual illusions

In a study that could help reveal how illusions are produced in the brain's visual cortex, researchers at the UCSD School of Medicine have found new evidence of rapid integration of auditory and visual sensations in the brain. Their findings, which provide new insight into neural mechanisms by which visual perception can be altered by concurrent auditory events, will be published online in the April 12 edition of the Journal of Neuroscience.

When subjects were shown a single flash of light interposed between two brief sounds, many subjects reported seeing two distinct flashes of light. Investigating the timing and location of the brain processes that underlie this illusory effect ?the illusion of seeing two flashes in the presence of two auditory signals, when only one flash actually occurs ?can reveal how information from different senses are integrated in the brain.

The study of 34 subjects was carried out in the laboratory of Steven A. Hillyard, Ph.D., UCSD professor of neurosciences. "This type of perceptual illusion has been described before," said first author Jyoti Mishra, graduate student in the Hillyard lab. "The surprising finding we made is that the illusion depends on a rapidly timed sequence of interactions between the auditory and visual cortical areas."

"This is part of a set of new findings by scientists in the field that show how integration of multiple sensations can happen much more rapidly than we thought before," said Mishra. "We show physiological evidence that visual and auditory stimulation might not be processed separately, then merged together, as previously assumed, but that an almost-simultaneous integration of the sensations may actually take place in the brain."

The UCSD scientists measured event-related potentials (ERPs), brain responses that are directly related to the perceptual experiences induced by sensory stimuli, using an electrophysiological or EEG recording procedure that measures electrical activity of the brain through the skull.

"In subjects who reported seeing a second flash, the ERP measurements showed a boost of activity within the visual cortex of the brain immediately after hearing the second sound," said Mishra, adding that the second sound amplified the brain activity stimulated by the first sound. Perception of the second illusory flash was also marked by a rapid enhancement of processing in the auditory cortex of the brain. By observing the auditory boost, the researchers could predict when subjects would report seeing the visual illusion of a second flash.

"Our results provide evidence that perception of the illusory second flash is based on a very rapid and dynamic interplay between the auditory and visual cortices of the brain ?on a time scale less than one tenth the blink of an eye." Mishra said. Interestingly, the pattern was very different between individuals who did or didn't see the second flash, indicating that the brain's wiring and the strength of integration between the different sensory cortices may differ between individuals, or even vary over time. "It suggests that there are consistent differences in the neural connectivity that are possibly shaped during one's development and through experience," she said.

Next, the researchers plan to look at whether or not attention affects these illusory sensations. These studies could shed light on how people deprived of one sensation often compensate by developing another ?for instance, blind people with a more acute sense of hearing.


'"/>

Source:University of California - San Diego


Related biology news :

1. Controversial drug shown to act on brain protein to cut alcohol use
2. Mouse brain cells rapidly recover after Alzheimers plaques are cleared
3. Mouse brain tumors mimic those in human genetic disorder
4. New imaging method gives early indication if brain cancer therapy is effective, U-M study shows
5. First atlas of key brain genes could speed research on cancer, neurological diseases
6. NYU study reveals how brains immune system fights viral encephalitis
7. Stem cells from brain transformed to produce insulin at Stanford
8. Birds brains reveal source of songs
9. Loves all in the brain: fMRI study shows strong, lateralized reward, not sex, drive
10. Revolutionary nanotechnology illuminates brain cells at work
11. A puzzle piece found in unraveling the wiring of the brain
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/26/2016)... Research and Markets has announced ... 2016-2020"  report to their offering.  , ,     (Logo: ... analysts forecast the global multimodal biometrics market to ... period 2016-2020.  Multimodal biometrics is being ... the healthcare, BFSI, transportation, automotive, and government for ...
(Date:4/15/2016)... -- A new partnership announced today will help life ... a fraction of the time it takes today, ... insurance policies to consumers without requiring inconvenient and ... rapid testing (A1C, Cotinine and HIV) and higi,s ... pulse, BMI, and activity data) available at local ...
(Date:4/14/2016)... 14, 2016 BioCatch ™, ... today announced the appointment of Eyal Goldwerger ... Goldwerger,s leadership appointment comes at a time ... the deployment of its platform at several of the ... which discerns unique cognitive and physiological factors, is a ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... Cancer experts from ... believe could be a new and helpful biomarker for malignant pleural mesothelioma. Surviving ... to read it now. , Biomarkers are components in the blood, tissue ...
(Date:6/27/2016)... 27, 2016  Liquid Biotech USA ... of a Sponsored Research Agreement with The University ... (CTCs) from cancer patients.  The funding will be ... correlate with clinical outcomes in cancer patients undergoing ... then be employed to support the design of ...
(Date:6/24/2016)... ... 24, 2016 , ... While the majority of commercial spectrophotometers and fluorometers use ... 6000i models are higher end machines that use the more unconventional z-dimension of 20mm. ... from the bottom of the cuvette holder. , FireflySci has developed several Agilent ...
(Date:6/23/2016)... Mass. , June 23, 2016   ... development of novel compounds designed to target cancer ... napabucasin, has been granted Orphan Drug Designation from ... the treatment of gastric cancer, including gastroesophageal junction ... stemness inhibitor designed to inhibit cancer stemness pathways ...
Breaking Biology Technology: