Impaired visual signals might contribute to schizophrenia symptoms

By observing the eye movements of schizophrenia patients while playing a simple video game, a University of British Columbia researcher has discovered a potential explanation for some of their symptoms, including difficulty with everyday tasks.

The research, published in a recent issue of the Journal of Neuroscience, shows that, compared to healthy controls, patients had a harder time tracking a moving dot on the computer monitor with their eyes and predicting its trajectory. But the impairment of their was not severe enough to explain the difference in their predictive performance, suggesting a breakdown in their ability to interpret what they saw.

Lead author Miriam Spering, an assistant professor of ophthalmology and visual sciences, says the patients were having trouble generating or using an "efference copy" – a signal sent from the eye movement system in the brain indicating how much, and in what direction, their eyes have moved. The efference copy helps validate visual information from the eyes.

"An impaired ability to generate or interpret efference copies means the brain cannot correct an incomplete perception," says Spering, who conducted the dot-tracking experiments as a postdoctoral fellow at New York University, and is now conducting similar studies at UBC. The brain might fill in the blanks by extrapolating from prior experience, contributing to , such as .

My vision would be a mobile device that patients could use to practice that skill, so they could more easily do common tasks that involve , such as walking along a crowded sidewalk.

"But just as a person might, through practice, improve their ability to predict the trajectory of a moving dot, a person might be able to improve their ability to generate or use that efference copy," Spering says. "My vision would be a mobile device that patients could use to practice that skill, so they could more easily do common tasks that involve motion perception, such as walking along a crowded sidewalk."

Related Stories

Writing in cursive with your eyes only

Jul 26, 2012

A new technology described in the paper published online on July 26 in Current Biology might allow people who have almost completely lost the ability to move their arms or legs to communicate freely, by usi ...

Barrow researchers unravel illusion

May 01, 2012

Barrow Neurological Institute researchers Jorge Otero-Millan, Stephen Macknik, and Susana Martinez-Conde share the recent cover of the Journal of Neuroscience in a compelling study into why illusions trick our brains. Barrow ...

More than just looking: Role of tiny eye movements explained

Feb 21, 2013

Have you ever wondered whether it's possible to look at two places at once? Because our eyes have a specialized central region with high visual acuity and good color vision, we must always focus on one spot at a time in order ...

Are people really staring at you?

Apr 09, 2013

(Medical Xpress)—People often think that other people are staring at them even when they aren't research led by the University of Sydney has found.

Recommended for you

Emotional adjustment following traumatic brain injury

Oct 24, 2014

Life after a traumatic brain injury resulting from a car accident, a bad fall or a neurodegenerative disease changes a person forever. But the injury doesn't solely affect the survivor – the lives of their spouse or partner ...

New ALS associated gene identified using innovative strategy

Oct 22, 2014

Using an innovative exome sequencing strategy, a team of international scientists led by John Landers, PhD, at the University of Massachusetts Medical School has shown that TUBA4A, the gene encoding the Tubulin Alpha 4A protein, ...

User comments