Dr. Grossman’s Blog

Study could lead to new therapies to help improve sight following trauma or stroke

Neuroscientists studying the mind’s ability to process images have completed the first empirical study to demonstrate how nerve cells in the visual cortex adapt to changing images. 

In the study, researchers at the University of Texas Health Science Center measured the effects of visual stimulation on the responses of multiple neurons whose electrical activity was measured simultaneously in animals. They examined the responses of a population of cells in visual cortex to dynamic stimuli (movie sequences displayed on a video monitor).

Results showed that brief exposure or adaptation to a fixed stimulus caused changes in the degree of cooperation between individual neurons and improved the efficiency with which the population of cells encoded information.

“Our perception of the environment relies on the capacity of neural networks to adapt rapidly to changes in incoming stimuli,” wrote senior author Valentin Dragoi.  “It is increasingly being realized that the neural code is adaptive, that is, sensory neurons change their responses and selectivity in a dynamic manner to match the changes in input stimuli.” The neural code is the set of rules that converts electrical impulses in the brain into thoughts, memories and decisions.

“Right now, we don’t know the causes of brain illnesses such as Alzheimer’s disease or disorders caused by trauma,” Dragoi said. “However, it is our belief that understanding not only how individual neurons work, but how they cooperate with their neighbors to impact the functions of the brain involved in diseases may help develop better diagnostic tools and therapies to improve visual function following trauma, stroke or disease, or even prevent brain disorder.”

SOURCE:  “Populations Of Brain Cells Adapt To Changing Images,” Dragoi, et al., Nature 452, 220-224 (13 March 2008).