Gladstone Scientists Map Process by which Brain Cells Form Long-Term Memories
Scientists at the Gladstone Institutes have deciphered how a protein called Arc regulates the activity of neurons—providing much-needed clues into the brain’s ability to form long-lasting memories. These findings, reported today in Nature Neuroscience, also offer newfound understanding as to what goes on at the molecular level when this process becomes disrupted.
Led by Gladstone Senior Investigator Steve Finkbeiner, MD, PhD, this research delved deep into the inner workings of synapses. Synapses are the highly specialized junctions that process and transmit information between neurons. Most of the synapses our brain will ever have are formed during early brain development, but throughout our lifetimes these synapses can be made, broken and strengthened. Synapses that are more active become stronger, a process that is essential for forming new memories. However, this process is also dangerous, as it can overstimulate the neurons and lead to epileptic seizures. It must therefore be kept in check.
Neuroscientists recently discovered one important mechanism that the brain uses to maintain this important balance: a process called “homeostatic scaling.” Homeostatic scaling allows individual neurons to strengthen the new synaptic connections they’ve made to form memories, while at the same time protecting the neurons from becoming overly excited. Exactly how the neurons pull this off has eluded researchers, but they suspected that the Arc protein played a key role…
But Dr. Finkbeiner and his team thought there was something else in play… In fact, the team’s experiments revealed that Arc acted as a master regulator of the entire homeostatic scaling process. During memory formation, certain genes must be switched on and off at very specific times in order to generate proteins that help neurons lay down new memories. From inside the nucleus, the authors found that it was Arc that directed this process required for homeostatic scaling to occur. This strengthened the synaptic connections without overstimulating them—thus translating learning into long-term memories.