A team of neuroscientists has identified an area of the human brain that is designed to sense barriers that define passable space around us, such as walls or ceilings, so that we can navigate our environment safely.
This area of the brain processes our spatial constraints at incredibly fast speeds and likely contributes to our instantaneous sense of our new surroundings. The study sheds new light on the complex calculations performed by our brains.
Senior Study Author Dr. Nikolaus Kriegescourt is Principal Investigator at Columbia University Mortimer B. Zuckerman Mind Brain Behavior Institute.
"Vision gives us an almost instantaneous sense of where we are in space, and in particular the geometry of surfaces - earth, walls - that restrict our movement. It seems so easy to us, but it requires the coordinated activity of several areas of the brain," - said the doctor Kriegescourt.
"How neurons work together to give us this sense of our surroundings remains a mystery. With this research, we are one step closer to solving this puzzle."
Using two state-of-the-art brain imaging technologies, the scientists examined the mental responses of volunteers when they were shown images of various three-dimensional scenes. The image may depict a typical room with three walls, a ceiling and a floor, but has then been drastically changed by the removal of the wall or ceiling.
“By doing this repeatedly for each participant, as we methodically alter the images, we could piece together how their brains encoded each scene,” said study author Dr. Linda Henriksson.
The occipital region, which is an intermediate level of cortical processing, was highlighted in the participants' brains.
"Previous research has shown that neurons encode scenes, not isolated objects," said Dr. Kriegescourt.
After analyzing the images of the brain, the team found that the activity in the regions mirrors the geometry of the scenes. Activity patterns in this area of the brain reflect the presence or absence of each component, such as a ceiling or wall, and project a detailed picture of the overall configuration.
The brain area seemed to ignore the appearance of the various components in order to focus solely on geometric patterns. The brain was able to get an idea of the layout of the room in just 100 milliseconds.
"The speed at which our brains perceive the underlying geometry of our environment indicates the importance of getting this information quickly," said Dr. Henriksson. "This is the key to understanding whether you are inside or outside, or what your options for movement might be."
In the future, the research team plans to implement virtual reality technology to create more realistic 3D environments for participants to experience.
“We would like to build computer vision systems that are more like our own brains, systems that have a specialized mechanism similar to what we see here in the human brain to quickly perceive the geometry of the environment,” said Dr. Kriegescourt.