'Sticky synapses' can impair new memories by holding on to old ones

May 26, 2014

(Medical Xpress)—A team of UBC neuroscientists has found that synapses that are too strong or 'sticky' can actually hinder our capacity to learn new things.

University of British Columbia researchers have discovered that so-called "sticky " in the brain can impair new learning by excessively hard-wiring old memories and inhibiting our ability to adapt to our changing environment.

Memories are formed by strong synaptic connections between nerve cells. Now a team of UBC neuroscientists has found that synapses that are too strong or "sticky" can actually hinder our capacity to learn new things by affecting , the ability to modify our behaviours to adjust to circumstances that are similar, but not identical, to previous experiences.

"We tend to think that strong retention of memories is always a good thing," says Fergil Mills, UBC PhD candidate and the study's first author. "But our study shows that cognitive flexibility involves actively weakening old memory traces. In certain situations, you have to be able to 'forget' to learn."

The study, published today in the Proceedings of the National Academy of Sciences, shows that mice with excessive beta-catenin – a protein that is part of the "molecular glue" that holds synapses together – can learn a task just as well as normal mice, but lacked the mental dexterity to adapt if the task was altered.

Credit: University of British Columbia

"Increased levels of beta-catenin have previously been reported in disorders such as Alzheimer's disease and Huntington's disease, and, intriguingly, patients with these diseases have been shown to have deficits in cognitive flexibility similar to those we observed in this study," says Shernaz Bamji, an associate professor in UBC's Dept. of Cellular and Physiological Sciences.

"Now, we see that changes in beta-catenin levels can dramatically affect learning and memory, and may indeed play a role in the cognitive deficits associated with these diseases," she adds. "This opens up many exciting new avenues for research into these diseases and potential therapeutic approaches."


To test cognitive flexibility in mice, researchers conducted an experiment where the mice were placed in a pool of water and had to learn to find a submerged hidden platform. The mice with excessive beta-catenin could learn to find the platform just as well as normal mice. However, if the platform was moved to a different location in the pool, these kept swimming to the platform's previous location. Even after many days of training, the 'sticky synapses' in their brains made them unable to effectively learn to find the new platform.

Explore further: New target for Alzheimer's drugs

More information: Cognitive flexibility and long-term depression (LTD) are impaired following β-catenin stabilization in vivo , PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1404670111

Related Stories

New target for Alzheimer's drugs

February 9, 2012

(Medical Xpress) -- Biomedical scientists at the University of California, Riverside have identified a new link between a protein called beta-arrestin and short-term memory that could open new doors for the therapeutic treatment ...

A mechanism to improve learning and memory

February 21, 2012

There are a number of drugs and experimental conditions that can block cognitive function and impair learning and memory. However, scientists have recently shown that some drugs can actually improve cognitive function, which ...

Recommended for you

New insights on how cocaine changes the brain

November 25, 2015

The burst of energy and hyperactivity that comes with a cocaine high is a rather accurate reflection of what's going on in the brain of its users, finds a study published November 25 in Cell Reports. Through experiments conducted ...

Can physical exercise enhance long-term memory?

November 25, 2015

Exercise can enhance the development of new brain cells in the adult brain, a process called adult neurogenesis. These newborn brain cells play an important role in learning and memory. A new study has determined that mice ...

Umbilical cells help eye's neurons connect

November 24, 2015

Cells isolated from human umbilical cord tissue have been shown to produce molecules that help retinal neurons from the eyes of rats grow, connect and survive, according to Duke University researchers working with Janssen ...

Brain connections predict how well you can pay attention

November 24, 2015

During a 1959 television appearance, Jack Kerouac was asked how long it took him to write his novel On The Road. His response – three weeks – amazed the interviewer and ignited an enduring myth that the book was composed ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.