Findings recently published in the Proceeding of the National Academy of Science could lead to a better understanding of how our memory changes with age.
According to John Hart, Jr., M.D. associate professor in the Reynolds Department of Geriatrics of the University of Arkansas Medical Sciences College of Medicine, and a co-author of the study, “This new approach to looking at mechanisms of memory via electrical rhythms raises a whole series of questions about how the brain operates and what happens when it doesn’t work properly,” he explained.
The study, conducted by Dr. Hart and colleagues from Johns Hopkins University, involves a unique explanation for how we recall memories. The medical researchers suggest that objects occur in your memory by uniting the different brain regions that make up various parts of the object you are trying to remember. For example, the memory of a dog includes uniting smell, sound, appearance and name.
By measuring the electrical rhythms that different parts of the brain use to communicate with each other, the team found when the memory of a dog occurs, the thalamus, an important region of the brain that connects areas together, actually regulates the rhythms that connect brain regions.
“Memory appears to be a constructive process in combining the features of the items to be remembered, rather than simply remembering each object as a whole form,” Dr. Slotnick explained. “The thalamus seems to direct or modulate the brain’s activity so that the regions needed for memory are connected.”
“It appears that the electrical signals synchronize the brain regions that store each part of an object’s memory so that those areas are connected,” Dr. Hart, said. “This co-activation of brain regions likely represents the memory of the object itself. It may also explain why we may remember something clearly, and other times we can only come up with parts of the item we are trying to remember. Many times we say ‘you know, it has humps, it lives in the desert …’ This may occur when the rhythms don’t synchronize with the regions properly. It could also explain why the memory will come to you at a later time.”
An important implication of the study’s association of the thalamus and rhythms to memory is that patients, including those who suffer from Alzheimer’s disease, who experience this sort of memory loss may not actually be losing information. Instead, the memory process is being disrupted.
“We want to try to figure out, based on this approach to memory function, what sort of neurotransmitters and brain regions are being disrupted during the memory process. Then we want to see if we can treat patients by regulating this disrupted memory circuit,” Dr. Hart explained.