From Sheba Medical Center via MedicalXpress: “People plan their movements, anticipate force of gravity by ‘seeing it’ through visual cues rather than ‘feeling it'”

1

From Sheba Medical Center, Israel

via

Medicalxpress bloc

MedicalXpress

January 24, 2020
Frontiers

1
Credit: CC0 Public Domain

Gravity is the unseen force that dominates our entire lives. It’s what makes walking uphill so difficult and what makes parts of our body eventually point downhill. It is unyielding, everywhere, and a force that we battle with every time we make a move. But exactly how do people account for this invisible influence while moving through the world?

A new study in Frontiers in Neuroscience used virtual reality to determine how people plan their movements by “seeing” gravity using visual cues in the landscape around them, rather than “feeling it” through changes in weight and balance. Ph.D. Student Desiderio Cano Porras, who worked in Dr. Meir Plotnik’s laboratory at the Sheba Medical Center, Israel and colleagues found that our capability to anticipate the influence of gravity relies on visual cues in order for us to walk safely and effectively downhill and uphill.

In order to determine the influence of vision and gravity on how we move, the researchers recruited a group of 16 young, healthy adults for a virtual reality (VR) experiment. The researchers designed a VR environment that simulated level, uphill, and downhill walking. Participants were immersed in a large-scale virtual reality system in which they walked on a real-life treadmill that was at an upward incline, at a downward decline, or remained flat. Throughout the experiment, the VR visual environment either matched or didn’t match the physical cues that the participants experienced on the treadmill.

Using this setup, the researchers were able to disrupt the visual and physical cues we all experience when anticipating going uphill or downhill. So, when participants saw a downhill environment in the VR visual scenery, they positioned their bodies to begin “braking” to go downhill despite the treadmill actually remaining flat or at an upward incline. They also found the reverse—people prepared for more “exertion” to go uphill in the VR environment even though the treadmill remained flat or was pointing downhill.

The researchers showed that purely visual cues caused people to adjust their movements to compensate for predicted gravity-based changes (i.e., braking in anticipation of a downhill gravity boost and exertion in anticipation of uphill gravitational resistance). However, while participants initially relied on their vision, they quickly adapted to the real-life treadmill conditions using something called a “sensory reweighting mechanism” that reprioritized body-based cues over visual ones. In this way the participants were able to overcome the sensory mismatch and keep walking.

“Our findings highlight multisensory interactions: the human brain usually gets information about forces from “touch” senses; however, it generates behavior in response to gravity by “seeing” it first, without initially “feeling” it,” says Dr. Plotnik.

Dr. Plotnik also states that the study is an exciting application of new and emerging VR tech as “many new digital technologies, in particular virtual reality, allow a high level of human-technology interactions and immersion. We leveraged this immersion to explore and start to disentangle the complex visual-locomotor integration achieved by human sensory systems.”

The research is a step towards the broader goal of understanding the intricate pathways that people use to decide how and when to move their bodies, but there is still work to be done.

Dr. Plotnik states that “This study is only a ‘snapshot’ of a specific task involving transitioning to uphill or downhill walking. In the future we will explore the neuronal mechanisms involved and potential clinical implications for diagnosis and treatment.”

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

MedicalXpress is a web-based medical and health news service that is part of the renowned Science X network. Medical Xpress features the most comprehensive coverage in medical research and health news in the fields of neuroscience, cardiology, cancer, HIV/AIDS, psychology, psychiatry, dentistry, genetics, diseases and conditions, medications and more.

Sheba Medical Center is dedicated to providing exceptional healthcare to all patients from all over the world. We are the largest hospital in Israel, and we set the standard of excellence in patient-focused care. Our state-of-the-art facilities are located on a comprehensive, all-inclusive campus with a full range of medical divisions and specialties. We have two Medical Tourism Tracks, for individuals and government bids, and treat each patient with advanced and holistic care based on integrated research and clinical practice.

Sheba’s core value is to constantly deliver personalized, expert medicine to everyone – with no limits or boundaries. We have treated thousands of patients from across the globe, including Russia, Ukraine, Cyprus, Kazakhstan, Georgia, Bulgaria, Romania, Switzerland, Hungary, the United States, and Nigeria. We offer an extensive range of custom-designed care in several languages, including advanced imaging technologies, laboratory testing, diagnostics, surgery, and progressive rehabilitation programs. To ensure the most optimized experience possible, each patient is assigned a dedicated medical coordinator to guide them through every step of their treatment at Sheba.