Why do you remember your mother’s birthday but not where you parked your car? A team of researchers led by McGill University has just unveiled one of the mysteries of long-term learning.
Our new memory is very fragile and prone to interference and forgetting. In order to become stable and persistent over time, they must undergo a memory consolidation phenomenon that can extend over a period of several months. This merging consists of a progressive realignment of the nerve circuits. This is what enables us to learn in the long term.
For years, protein synthesis has been known to play an important role in strengthening memory. A team of researchers led by McGill University has discovered this protein. This breakthrough could contribute to the development of preventive and post-diagnostic treatments against disorders that include memory deficits such as Alzheimer’s disease and autism. According to Vijendra Sharma, the lead author of the article published in the magazine Temperate nature, ” This could lead to new therapeutic interventions targeted to improve memory. ”
To study the effect of protein synthesis on memory, the team of researchers genetically modified the eIF2α pathway of transgenic mice (the molecular pathway is a series of actions that can lead to the assembly of new molecules such as a protein). “Mutation of this pathway improves protein synthesis,” says Vijendra Sharma. According to previous studies, this pathway will be a limiting component in neurodevelopmental and neurodegenerative diseases.
Two networks are involved in the memory consolidation process: the excitatory neuron network and the inhibitory neuron network. Vigendra Sharma explains that “the balance between excitement and inhibition regulates brain function and the formation of memories”.
The researchers first stimulated protein synthesis via the eIF2α pathway in excitatory neurons in the hippocampus. In addition to inducing a change in synapses, which is where neurons communicate with each other, this stimulation improved the formation of memories.
Then they reproduce the same process with inhibitory neurons. They observed that by stimulating a specific class of inhibitory neurons, the endogenous somatostatin neurons, there was an increase in long-term memory by modulating the elasticity of nerve connections.
Promising inhibitory neurons
According to Vijendra Sharma, it’s great to be able to demonstrate this new role for inhibitory neurons. So far, researchers have assumed that the eIF2α pathway only regulates memory through excitatory neurons.
“In many models of autism and neurodevelopmental disorders, genetic mutations alter the activity of molecular pathways [comme eIF2α], Which may lead to behavioral inflexibility and cognitive impairment. ”Consequently, this finding on the eIF2α pathway may make it possible to better target the following therapeutic interventions to improve memory.