A memory pill? The contributions of cognitive neuroscience to the study of memory

In the first weeks of the new year, resolutions are often accompanied by attempts to learn new behaviors that improve health. We hope that bad habits will disappear and that new healthy habits will become automatic.

But how can our brain be reprogrammed to learn and maintain a new health habit?

Read more:
Making New Year's resolutions personal could actually keep them

Hebrew learning

In 1949, Canadian psychologist Donald Hebb proposed Hebbian 's theory of learning to explain how a task of learning is transformed into a long – term memory. In this way, healthy habits are automatically preserved after their continuous repetition.

Learning and memory are a consequence of how our brain cells (neurons) communicate with each other. When we learn, neurons communicate through molecular transmissions that jump through synapses producing a memory circuit. Known as long-term potentiation (LTP), the more a learning task is repeated, the more the transmission continues and the stronger the memory circuit. It is this unique ability of neurons to create and strengthen synaptic connections by repeated activation that leads to Hebbian learning.

Memory and the seahorse

Understanding the brain requires investigation through different approaches and many specialties. The field of cognitive neuroscience initially developed through a small number of pioneers. Their experimental designs and observations laid the foundation for our understanding of learning and memory today.

Donald Hebb's contributions to McGill University remain the driving force in explaining memory. Under her supervision, neuropsychologist Brenda Milner studied a patient with impaired memory following a lobectomy. Subsequent studies with neurosurgeon Wilder Penfield allowed Milner to expand his studies of memory and learning in patients following brain surgery.

Milner's breakthrough came in the study of a patient who had had the hippocampus removed on both sides of the brain, resulting in amnesia. She noticed that the patient could still learn new tasks but could not transfer them to long-term memory. In this way, the hippocampus has been identified as the site required for the transfer of short-term memory to the long-term memory where Hebbian learning takes place.

In 2014, at the age of 95, Milner won the Norwegian Kavli Prize in Neuroscience for his discovery in 1957 of the importance of the hippocampus for memory.

Neuroscientist John O'Keefe was also honored in 2014 by the neuroscientist, who discovered that the hippocampus also hosted location cells to create a cognitive map that allows us to move from one place to another through our memory. O & # 39; Keefe also received the Nobel Prize in Medicine 2014.

Neuroscientist Tim Bliss discovered that repeated neuronal activation in the hippocampus leads to memory. For this research, Bliss received the Lundbeck Foundation Brain Prize in 2016.

Together, Milner, Bliss, and O'Keefe established the paradigm of Hebb and his famous axiom: "The neurons that shoot together, connect together."

Memory in non-human animals

Major advances in non-human organisms tell us about the mechanisms of memory that can be applied to humans. Eric Kandel of Columbia University received the 2000 Nobel Prize for Medicine for his wise choice of the sea slug (Aplysia) to understand Hebrew learning.

Kandel provided conclusive evidence that memory was a consequence of repeated signaling to a neuron responding to a learning task that would trigger the production of ribonucleic acid (RNA). The end result was a new protein expression resulting in increased synaptic connections.

The next leap forward occurred at McGill when molecular biologist Nahum Sonenberg discovered a key mechanism that governs the formation of memory in the hippocampus, namely the factor of initiation of protein synthesis. The discovery revealed that during the formation of memory, it is the factor of initiation of protein synthesis in the hippocampal neurons that affects the reprogramming necessary for the generation of "wiring" new synaptic connections.

A memory pill?

Sonenberg's work has revolutionized the world of scientists working on how protein synthesis is controlled. Molecular biologist Peter Walter, one of the most prominent in the field, was contacted by Sonenberg. Together, they identified a chemical compound that they named ISRIB, which would affect the same protein synthesis initiation factor whose importance had been discovered by Sonenberg.

The results were dramatic, with an incredible improvement in memory in mice after the administration of ISRIB. Walter has now extended this notion to restoring memory in recovering mice after brain trauma.

Today, all advances are carefully examined, because memory disorders in men – from age-related memory loss to dementia, to Alzheimer's disease – reach levels close to the pandemic in the elderly. The World Health Organization estimates that dementia is diagnosed at 10 million patients a year, with an estimated total of 50 million.

John Bergeron thanks Kathleen Dickson as co-author.