What makes memories so detailed and lasting? Newly discovered system of learning

Small red dots are inhibitory nerve cells within the hippocampus of the brain. The optogenetic tool shown in green allows researchers to measure the strength of the message to other nerve cells using flashes of light. Sincerely: Matt Udkis

In the coming years, personal memories of COVID-19 There is a possibility of an epidemic with precision and clarity in our mind, which is different from other memories of 2020. This process that makes scientists possible for many decades, but led by research University of Bristol It has made it a breakthrough to understand how memories can be so different and longer without being isolated.

Published in, study Nature communication, Described to stabilize memories and reduce interference between them, describes a new discovery mechanism of learning in the brain. Its findings also provide new insights into how humans form expectations and make accurate predictions about what might happen in the future.

Memories are formed when the relationship between the nerve cells sending and receiving signals from the brain becomes stronger. This process has long been associated with changes that stimulate neighboring nerve cells in the hippocampus, an area of ​​the brain important for memory formation.

These excitatory connections should be balanced with inhibitory connections, which dampen nerve cell activity for healthy brain function. The role of changes in inhibitory connection strength was not previously considered, and researchers found that inhibitory connections between nerve cells, known as neurons, could be similarly strengthened.

Working closely with computational neuroscientists Imperial College London, The researchers showed how this allows the stabilization of memory representations.

Their findings highlight for the first time how two different types of inhibitory connections (neurons expressing parvalbumin and somatostatin) can also differ and increase their strength, such as excitatory connections. In addition, computational modeling demonstrated this inhibitory learning, enabling the hippocampus to stabilize changes in excitatory connection strength, which prevent information from disrupting memories that might be disrupted.

Research Associate of the School of Physiology, Pharmacology and Neuroscience First author Drs. Matt Udakis said: “When we discovered these two types of inhibitory neurons we were really excited and could change our connections.

“It provides an explanation for what we all know is true; Memories do not disappear as soon as we gain a new experience. These new findings will help us understand why this is so.

“Computer modeling gave us important information about how inhibitory learning makes memories stable over time and not susceptible to interference. This is really important because it is not already clear how different memories are accurate and robust. Can stay. ”

The research was funded by the UKRI’s Council on Biotechnology and Biological Sciences Research, which has provided more funding to the teams to develop this research and test their predictions from these findings by measuring the consistency of memory representations.

Professor Jack Mellor, senior author in neuroscience at the Center for Synaptic Plasticity, said: “Memories form the basis of our expectations about future events and enable us to make more accurate predictions. What the brain is constantly doing is meeting our expectations of reality, figuring out where the mismatches are, and using this information to determine what we need to learn.

“We believe that what we have discovered plays an important role in assessing how accurate our predictions are and therefore what is important new information. In the current climate, our ability to manage our expectations and make accurate predictions has never been more important.

“It is also a great example of how research on the interfaces of two different disciplines can actually provide exciting science with new insights. Memory researchers within Bristol Neuroscience constitute one of the largest communities of memory-focused research in the UK across a wide range of expertise and perspectives. It was a great opportunity to work together and answer these big questions, which neuroscientists have struggled with for decades and have broad implications. ”

References: Matt Udakis, Victor Pedrosa, Sophie EL Chamberlain, Claudia Klopath and Jack R. Mellor, 2 September 2020, “Parvalumin-specific plasticity shaping hippocampal output to parvalbumin and somatostatin inhibitor synapse in CA1 pyramidal neurons”. Nature communication.
DOI: 10.1038 / s41467-020-18074-8