Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Impaired visual signals might contribute to schizophrenia symptoms

29.07.2013
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, schizophrenia 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 eye movements 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 psychotic symptoms, such as hallucinations.

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.

"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."

Study method

For the UBC study, schizophrenia patients, along with a control group, were asked to predict the trajectory of a small dot that appeared briefly on a monitor as it moved toward a vertical line. As an infrared-equipped video camera tracked their eye movements, participants would call out whether it would hit or miss the line. The schizophrenia patients performed significantly worse than the control group in predicting hits and misses, and they were also not as good at tracking the dot with their eyes.

Schizophrenia is a brain disorder affecting about one per cent of the population that often causes people to hear voices that others don't hear or see things that others don't see. They can also be incoherent when talking, or may sit quietly for hours without moving or talking. People with schizophrenia often have poor motion perception and eye movements, leading them to bump into people while walking or making it a challenge to cross a street. They often cannot perform even simple tasks like preparing a shopping list or reading a transportation map.

Impact for Parkinson's patients? Spering is now conducting the same experiment on people with Parkinson's disease, a movement disorder caused by the lack of the brain chemical dopamine. In addition to muscle tremor and stiffness, Parkinson's patients have poor visual perception and impaired eye movements. Spering is trying to see if the two are connected; if so, eye-movement exercises might improve vision in Parkinson's patients.

Better baseball through science: Spering is working with UBC baseball head coach Terry McKaig, who sought out her expertise in visual neuroscience to improve his team's hitting. She will soon begin testing players' eye movements while they hit balls in a batting cage. "Coach McKaig is extremely interested in the science, and excited about the possibility to include vision training into the team's daily routine," Spering says. "We are using a highly scientific approach to first understand the mechanisms that could lead to improvements, and then using our knowledge to enhance performance in the field."

Brian Lin | EurekAlert!
Further information:
http://www.ubc.ca

More articles from Health and Medicine:

nachricht Spread of deadly eye cancer halted in cells and animals
13.11.2018 | Johns Hopkins Medicine

nachricht Breakthrough in understanding how deadly pneumococcus avoids immune defenses
13.11.2018 | University of Liverpool

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

The dawn of a new era for genebanks - molecular characterisation of an entire genebank collection

13.11.2018 | Life Sciences

Fish recognize their prey by electric colors

13.11.2018 | Life Sciences

Ultrasound Connects

13.11.2018 | Awards Funding

VideoLinks
Science & Research
Overview of more VideoLinks >>>