Not only does the brain find a way to compensate for our constantly flickering gaze, but researchers at the Salk Institute for Biological Studies have found that it actually turns the tables and relies on eye movements to recognize partially hidden or moving objects. Their findings will be published in a forthcoming issue of Nature Neuroscience.
"You might expect that if you move your eyes, your perception of objects might get degraded," explains senior author Richard Krauzlis, Ph.D., an associate professor in the Systems Neurobiology Laboratory at the Salk Institute. "The striking thing is that moving your eyes can actually help resolve ambiguous visual inputs."
Our eyes move all the time, whether to follow a moving object or to scan our surroundings. On average, our eyes move several times a second – in fact, in a lifetime, our eyes move more often than our heart beats. "Nevertheless, you don't have the sense that the world has just swept across or rotated around you. You sense that the world is stable," says Krauzlis.
Just like high-end video cameras, the brain relies on an internal image stabilization system to prevent our perception of the world from turning into a blurry mess. Explains lead author Ziad Hafed, Ph.D. "Obviously, the brain has found a solution. In addition to the jumpy video stream, the visual system constantly receives feedback about the eye movements that the brain is generating."
Hafed and Krauzlis took the question of how the brain is able to maintain perception under less than optimal circumstances one step further. "If you think of the video stream as a bunch of pixels coming in from the eyes, the real challenge for the visual system is to decide which pixels belong to which objects. We wondered whether information about eye movements is used by the brain to solve this difficult problem," says Hafed, who is an NSERC (Canada) and Sloan-Swartz post-doctoral researcher at the Salk Institute.
Krauzlis explains that the human brain recognizes objects in everyday circumstances because it is very good at filling in missing visual information. "When we see a deer partially hidden by tree trunks in a forest, we can still segment the visual scene and properly interpret the individual features and group them together into objects," he says.
However, even though recognizing that deer is effortless for us, it is not a trivial accomplishment for the brain. Teaching computers to recognize objects in real life situations has proven to be an almost insurmountable problem. Artificial intelligence researchers have spent much time and effort trying to design robots that can recognize objects in unconstrained situations, but so far, their success has been limited.
To determine whether eye movements actually help the brain recognize objects, Hafed and Krauzlis asked whether people perceived an object better when they actively moved their eyes or when they stared at a given point in space. Human subjects watched a short video that allowed them to glimpse a partially hidden chevron shape that moved in a circle.
When they kept their eyes still by fixating on a stationary spot, observers perceived only random lines moving up and down. But when they moved their eyes such that the input video streams through them were unaltered, viewers easily recognized the lines as a circling chevron.
"It turns out that eye movements not only help with image stabilization, but that this additional input also plays a fairly important role for the perception of objects in the face of all the challenges that real life visual scenes pose – that objects are obscured or are moving, and so on," says Hafed.
Gina Kirchweger | EurekAlert!
Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München
Second research flight into zero gravity
21.10.2016 | Universität Zürich
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences