Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Optic Flow: A Step in The Right Direction

19.11.2007
The way objects appear to stream by us as we move through the world is a phenomenon called optic flow. Think of the street signs and storefronts that sail across the car windshield as we drive. That’s optic flow in action. Brown University cognitive scientists have now shown, in research to be featured on the cover of Current Biology, that optic flow plays a critical role in continuously recalibrating our steps as we walk.

The motion we perceive with our eyes plays a critical role in guiding our feet as we move through the world, Brown University research shows.

The work was conducted in Brown’s Virtual Environment Navigation Lab, or VENLab, one of the largest virtual reality labs in the country. It appears online in Current Biology and will be featured on the journal’s Dec. 4, 2007, cover. The findings shed important new light on the phenomenon of optic flow, the perceived motion of visual objects that helps in judging distance and avoiding obstacles while walking, driving and even landing a plane.

Perception in action, or the intersection of how we see and how we move, is the focus of research in the laboratory of William Warren, chairman of Brown’s Department of Cognitive and Linguistic Sciences. In the VENLab, Warren and his team have studied optic flow by having human subjects wear virtual reality goggles and navigate through virtual obstacles in the darkened room.

... more about:
»Brain »Optic »Visual »walk

In 2001, the Warren lab showed for the first time that people use optic flow to help them steer toward a target as they walk. But what happens when you are standing still? If you are not walking and not getting the constant stream of visual information that optic flow provides, how do you begin moving toward a target? How do you know which way to direct your first step?

To get an answer to this question, the team created a virtual display that simulates a prism, bending light so that the visual scene shifts to one side. The target – in this case, a virtual doorway toward which subjects were told to walk – appeared to be farther to the right than it actually was. A total of 40 subjects ran through about 40 trials each, with everyone trying to walk through the virtual doorway while wearing the simulated prism. Half those subjects had optic flow, or a steady stream of visual information, available to them. The other half did not.

The researchers found that, on average, all 40 subjects missed the doorway by about five feet on the first few steps. But after a while, subjects adapted and were able to walk straight toward the doorway. Then the simulated prism was removed, and subjects were again asked to walk to the virtual doorway. Surprisingly, they all missed their mark on the opposite side because their brains and bodies had adapted to the prism. After a few tries, subjects quickly readjusted again and were able to walk straight to the doorway.

Hugo Bruggeman, a postdoctoral research fellow in the Warren lab who led the research, said the kicker came when they compared data from subjects who had optic flow available during the trials with data from those who did not. When subjects had optic flow, they took a straight path toward the doorway and made it, on average, in just three tries. When optic flow was eliminated, and subjects had only a lone target to aim for, it took an average of 20 tries before they walked straight to the target.

“With optic flow, it is easier to walk in the right direction,” Bruggeman said. “Subjects adapted seven times faster. This suggests that with a continuous flow of visual information, your brain allows you to rapidly and accurately adapt your direction of walking. So we’re constantly recalibrating our movements and our actions based on information such as optic flow.”

This finding could have practical applications, particularly in robotics, where it can be used to produce machines with more accurate guidance capabilities. But Warren said the real value of the work rests with the deeper scientific principle it points up.

“We tend to think that the structures of the brain dictate how we perceive and act in the world,” Warren said. “But this work shows that the world also influences the structures of the brain. It’s a loop. The organization in the brain must reflect the organization and information in the world. And this is a universal principle. All animals that move use optic flow to navigate. So whether you’re a fly landing on a leaf or a pilot landing on a runway, you may be using the same source of sensory information to carry out your task.”

Wendy Zosh, a graduate student in the Department of Cognitive and Linguistic Sciences, also assisted in the research.

The National Eye Institute funded the work.

Wendy Lawton | EurekAlert!
Further information:
http://www.brown.edu

Further reports about: Brain Optic Visual walk

More articles from Life Sciences:

nachricht Discovery of a Key Regulatory Gene in Cardiac Valve Formation
24.05.2017 | Universität Basel

nachricht Carcinogenic soot particles from GDI engines
24.05.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Life Sciences >>>

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 >>>