Navigation Links
How do we make sense of what we see?

M.C. Eschers ambiguous drawings transfix us: Are those black birds flying against a white sky or white birds soaring out of a black sky? Which side is up on those crazy staircases?

Lines in Escher's drawings can seem to be part of either of two different shapes. How does our brain decide which of those shapes to "see?" In a situation where the visual information provided is ambiguous -- whether we are looking at Escher's art or looking at, say, a forest -- how do our brains settle on just one interpretation?

In a study published this month in Nature Neuroscience, researchers at The Johns Hopkins University demonstrate that brains do so by way of a mechanism in a region of the visual cortex called V2.

That mechanism, the researchers say, identifies "figure" and "background" regions of an image, provides a structure for paying attention to only one of those two regions at a time and assigns shapes to the collections of foreground "figure" lines that we see.

What we found is that V2 generates a foreground-background map for each image registered by the eyes," said Rudiger von der Heydt, a neuroscientist, professor in the university's Zanvyl Krieger Mind/Brain Institute and lead author on the paper. "Contours are assigned to the foreground regions, and V2 does this automatically within a tenth of a second.

The study was based on recordings of the activity of nerve cells in the V2 region in the brain of macaques, whose visual systems are much like that of humans. V2 is roughly the size of a microcassette and is located in the very back of the brain. Von der Heydt said the foreground-background map generated by V2 also provides the structure for conscious perception in humans.

Because of their complexity, images of natural scenes generally have many possible interpretations, not just two, like in Eschers drawings, he said. In most cases, they contain a variety of cues that could be used to identify fore- and background, but oftentimes, these cues contradict each other. The V2 mechanism combines these cues efficiently and provides us immediately with a rough sketch of the scene.

Von der Heydt called the mechanism "primitive" but generally reliable. It can also, he said, be overridden by decision of the conscious mind.

Our experiments show that the brain can also command the V2 mechanism to interpret the image in another way," he said. "This explains why, in Eschers drawings, we can switch deliberately" to see either the white birds or the dark birds, or to see either side of the staircase as facing "up."

The mechanism revealed by this study is part of a system that enables us to search for objects in cluttered scenes, so we can attend to the object of our choice and even reach out and grasp it.

We can do all of this without effort, thanks to a neural machine that generates visual object representations in the brain, von der Heydt said. Better yet, we can access these representations in the way we need for each specific task. Unfortunately, how this machine works is still a mystery to us. But discovering this mechanism that so efficiently links our attention to figure-ground organization is a step toward understanding this amazing machine.

Understanding how this brain function works is more than just interesting: It also could assist researchers in unraveling the causes of and perhaps identifying treatment for visual disorders such as dyslexia.


Contact: Lisa DeNike
Johns Hopkins University  

Related medicine news :

1. Its a knock out: eIF4E-specific anti-sense oligonucleotides knock down cancer
2. Countering Colds With Common Sense
3. Sense of taste different in women with anorexia nervosa
4. Compromise SCHIP Deal Substitutes Ideology for Common Sense
5. Penn study suggests professional welders at risk for loss of sense of smell
6. Majority of House of Representatives Support Common-Sense Fix to Medicare Part D Prescription Drug Plan
7. Ex-Head of Menarini Diabetes Unit Launches WaveSense Europe
8. Redsense Medical Receives FDA Approval for Blood Loss Detection Device
9. Bayer Awards Making Science Make Sense Grant to Girl Scouts
Post Your Comments:
Related Image:
How do we make sense of what we see?
(Date:12/1/2015)... ... December 01, 2015 , ... December 1, 2015 ... of the company’s growing product line of food safety and seafood fraud prevention ... (Oncorhynchus nerka) – allow InstantLabs to offer fast, reliable species identification for the ...
(Date:12/1/2015)... York, NY (PRWEB) , ... December 01, 2015 ... ... of non-traumatic limb amputations in the United States. Podiatrists are well aware that ... to adopt therapeutic behaviors) are often catastrophic contributors to diseases of the diabetic ...
(Date:12/1/2015)... (PRWEB) , ... December 01, 2015 , ... ... Center of Excellence (BHCOE) today announced that the organization has awarded Education and ... Francisco, with a Distinguished Award. The award celebrates exceptional special needs providers that ...
(Date:12/1/2015)... ... December 01, 2015 , ... ... Effective Post-Affiliation Integration ,” addresses a main “pain point” for merging or aligning ... results, once a deal is signed. This quick-read guidance suggests that failing ...
(Date:12/1/2015)... Beverly Hills, CA (PRWEB) , ... December 01, ... ... honored by Modern Luxury’s Angeleno Magazine as a Modern Man for 2015. ... luxury lifestyle publisher in the United States. Established in 1994, Modern Luxury includes ...
Breaking Medicine News(10 mins):
(Date:12/1/2015)... and PITTSBURGH , Dec. ... announced that it expects to be the first to ... funded by international donors, TLE400 (Tenofovir Disoproxyl Fumarate 300 ... for $99 per patient, per year. Mylan partnered with ... The significantly reduced price could generate savings of tens ...
(Date:12/1/2015)... Dec. 1, 2015  Six months of adjunctive metformin therapy ... 1 diabetes, according to new research from T1D Exchange ... may have a beneficial effect on measures of obesity, including ... of the Journal of the American Medical Association , ... effect of metformin on overweight and obese adolescents with type ...
(Date:12/1/2015)... 2015 ... of the "2016 Europe Enteric ... Coli, Enterovirus, Rhinovirus, Rotavirus, Salmonella, Shigella, ... offering. --> ) ... "2016 Europe Enteric Disease Testing ...
Breaking Medicine Technology: