Learning, remembering something, and retrieving memories are supported by multiple discrete groups of neurons connected within and across key regions of the brain. A new study by the Universities of Bristol and Heidelberg finds that if these neural clusters fail to sync together at the right time, memories are lost.
How do you keep track of what to do next? What happens in the brain when your mind goes blank? Short-term memory depends on two major brain regions: the hippocampus and the prefrontal cortex. The researchers set out to determine how these brain regions interact with each other during the formation, maintenance and recall of memories at the level of specific groups of neurons. The study, published in the journal Current Biology, also wanted to understand why memory sometimes fails.
“Neural clusters” — groups of neurons that join forces to process information — were first proposed more than 70 years ago, but have proven difficult to define precisely.
Using brain recordings in mice, the research team showed that memory encoding, storage and retrieval is supported by dynamic interactions involving multiple neuronal groups that form within and between the hippocampus and the prefrontal cortex. When coordination of these gatherings failed, the animals made mistakes.
Dr Michał Kočević, Associate Professor of Neuroscience at Gdańsk University of Technology, former PhD student at the University of Bristol, and lead author, said: “Our findings make potential therapeutic interventions for memory recovery more difficult to target in space and time. On the other hand, our findings have limited Critical processes that determine the success or failure of memory.These represent viable targets for therapeutic interventions at the level of neuronal assembly interactions.”
Matt Jones, Professor of Neuroscience in Bristol’s School of Physiology, Pharmacology, Neuroscience and Neuroscience and senior author on the paper, added: “Our findings add evidence that the neural substrates of memory are more distributed in anatomical space and dynamic across time than previously thought. Based on neuropsychological models.”
The next steps for the research will be to modify neuronal assembly interactions, either with drugs or by stimulating the brain, which Dr. Kocevitch is currently doing in human patients, to test whether disrupting or increasing them will impair or enhance recall. The research team hypothesizes that the same mechanisms would work in human patients to restore impaired memory functions in a specific brain disorder.