UBC Faculty of Medicine researchers have discovered that so-called sticky synapses in the brain can impair new learning by excessively hard-wiring old memories and inhibiting our ability to adapt to a changing environment. Memories are formed by strong synaptic connections between nerve cells. A team of UBC neuroscientists has found that synapses that are too strong can hinder people’s capacity to learn new things by affecting the ability to modify behaviors to adjust to circumstances that are similar, but not identical, to previous experiences. Mr Fergil Mills, UBC PhD candidate and the study’s first author, notes that cognitive flexibility involves actively weakening old memory traces—in certain situations, you have to be able to forget to learn. 

The study shows that mice with excessive beta-catenin can learn a task just as well as normal mice, but lacked the mental dexterity to adapt if the task was altered. Professor Shernaz Bamji from UBC’s Department of Cellular and Physiological Sciences notes that increased levels of betacatenin have previously been reported in disorders such as Alzheimer disease and Huntington disease, and patients with these diseases have been shown to have deficits in cognitive flexibility similar to those observed in the study. Changes in beta-catenin levels can dramatically affect learning and memory, and may play a role in the cognitive deficits associated with these diseases. The study, “Cognitive Flexibility and Long-Term Depression (LTD) are Impaired Following β-catenin Stabilization in Vivo,” is published in June 2014 issue of the Proceedings of the National Academy of Sciences and is available online at www.pnas.org/content/early/2014/05/22/1404670111 [8].