Sugar affects the brain's "plasticity" which helps in learning, memory and recovery

Can you recognize people you haven't seen in years, but easily forget what you had for breakfast yesterday? Our brains are constantly rearranging circuits to remember familiar faces or learn new skills, but the molecular basis of this process is not fully understood. Today, scientists report that sulfuric acid groups on complex sugar molecules called glycosaminoglycans (GAGs) influence the "plasticity" of the mouse brain. Determining the function of glycosaminoglycans can help us understand the principles of human memory and learning, and provide ways to repair neural connections after injury.

Complex sugar molecules control the formation of the networks around neurons

that surround them and help stabilize connections in the brain. Source: Laboratory of Linda Hsieh-Wilson

The researchers presented their findings on Aug. 16 at the Fall meeting of the American Chemical Society (ACS). The Fall 2023 Meeting of the American Chemical Society will be held August 13-17 in a combination of virtual and live, with approximately 12,000 presentations on a variety of scientific topics.

Complex sugars and brain plasticity

The sugars that sweeten a fruit, candy or cake are actually just a few simple varieties of sugars. When they are connected in series, they can form a variety of complex sugars. Gags are formed by attaching other chemical structures, including sulfuric acid groups.

"If we study the chemical structure of GAGs in the brain, we can understand the plasticity of the brain and hopefully use this information to restore or strengthen neural connections in memory in the future," said Dr. Linda Hsieh-Wilson, principal investigator of the project who presented the research at the meeting.

"These sugars regulate many proteins, and their structures change during development and during disease," she explains. Shea Wilson is currently with the California Institute of Technology (Caltech).

In the brain, the most common form of GAG is chondroitin sulfate, which is found in the extracellular matrix around many cells in the brain. Chondroitin sulfate also forms structures called "perineuronal nets," which wrap around individual neurons and stabilize the synaptic connections between them.