Eye Cells

Source: 2010 Gemini Research [http://www.ntnu.no/gemini/2010_autumn/7.htm]

Problems with maths?

Troubles with handwriting – and motor skills? The explanation for your difficulties may be in the workings of the cells in your eyes.

Published October, 2010

Inside the eye, the retina contains a number of cells that respond to specific types of stimuli. Some react to certain colours, while others react to contrast or movement. These cells individually gather information that combined provides our overall visual experience.

One group of cells is called magno cells. These are the cells that respond to rapid movements, transmitting signals from the eye to the brain. The information they send transforms what we see into live video. Without these cells, our brains would only perceive a series of still photos with no direct relationship, much like a comic book.

NTNU researchers suspect that the failure of magno cells to work the way they should may explain multiple learning disabilities and developmental problems.

From motor skills to maths problems

Imagine that you are trying to catch a ball. If you can’t quite perceive how the ball travels in relation to your body, you will be a bit awkward when you try to catch it. Or, as the experts say: Your motor skills are less precise than they should be. But individuals who suffer from motor skill difficulties often have other problems too: Between

three and eight per cent of school children have great difficulty learning mathematics (dyscalculia). About half of these individuals also have reading difficulties (dyslexia), and

motor development problems.

It has long been known that several types of learning disabilities often occur together. But the cause for this has not been understood.

Tested ten-year-olds

Professor Hermundur Sigmundsson studies the general principles behind learning, as well as learning disabilities. Sigmundsson is the driving force behind a study that shows that children who have extensive mathematical difficulties also have significantly poorer visual perception associated with rapid changes in the enviroment.

The study was carried out as follows: All of the 10-year-olds from two schools were given a mathematics test. Those with both the highest and lowest scores were given further tests. These two groups went through two socalled psycho-physical tests, where their visual processing was tested. The first test concerned the ability to follow dots on the screen which moved in different patterns, both predictable and unpredictable. This test revealed how well students were able to follow and anticipate predictable movements in relation to accidental movements. In other words, the test quantified the pupils’ ability to perceive rapid changes in the environment.

The second test was a control test that examined the ability to perceive form, using circles. This test did not include movement. The differences between the two groups were quite high in the test with the moving dots. Those with the lowest maths skills also scored lowest on this test. But there was no difference between the test scores of the two

groups for the control test.

Small dysfunction – big effect

The test is the final confirmation of the mechanism that Sigmundsson and his colleagues believe lies behind the specific learning disabilities. It all relates to how our visual system processes information from the environment, through, among others, magno cells. If something goes a bit wrong here, the consequences are significant and result in different types of learning disabilities.

“This demonstrates that when we find evidence of learning disabilities in children in one area, we should expect to find learning difficulties in other areas, too,” the professor says.

“And when we know the source of the problem, it makes it easier to create and adapt programmes so children get the most out of them.”

New teaching techniques

Sigmundsson notes that understanding the underlying causes of learning disabilities can lead to a new approach to pedagogical methods. Children with dysfunctional magno cells probably need more specific tools to help them understand visual information than we previously thought.

“The educational challenge is finding teaching techniques that make it easier for visual information to get to the areas of the brain where it will be processed further,” Sigmundsson says.

Hege Tunstad

Contact: Hermundur Sigmundsson, Department of Psychology, NTNU

Phone: : +47 908 86 279

Email: hermundurs@svt.ntnu.no

This article is also published at EarthSky