Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How Do We Make Sense of What We See?

21.11.2007
Johns Hopkins researchers identify how brains
rationalize ambiguous visual data

M.C. Escher's ambiguous drawings transfix us: Are those black birds flying against a white sky or white birds soaring out of a black sky?


M.C. Escher

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.

Rudiger von der Heydt

"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 Escher's 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 Escher's drawings, we can switch deliberately" to see either the white birds or the dark birds.

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.

Other authors include Fangtu T. Qiu and Tadashi Sugihara, both of the Zanvyl Krieger Mind-Brain Institute. Funding for the research was provided by the National Institutes of Health.

Lisa DeNike | EurekAlert!
Further information:
http://www.jhu.edu
http://www.mb.jhu.edu/vonderheydt.asp
http://neuroscience.jhu.edu/RudigervonderHeydt.php

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>