Boosting aging memory and reversing cognitive decline such as dementia and Alzheimer’s has been the goal of scientists for many years. The search is intensive and relentless.
Designing a medication to enhance memory might currently be the stuff of science fiction, but scientists are getting closer and it may soon become a happy reality. As mechanisms of memory formation are discovered, new drugs and enhancement therapies are formulated and applied.
Boosting Aging Memory: The Hippocampus
The hippocampus plays a vital role in memory formation. A region of the hippocampus referred to as CA1 is particularly important.
For instance, in a study testing individuals with damage to their CA1 region, found they had a severe learning impairment. Another study that tested similar patients found severe impairments in autobiographical and episodic memory.
The hippocampus is heavily influenced by the neurotransmitter serotonin but its exact role has remained unclear. The team involved in this study wanted to dig into this a little deeper.
To inspect serotonin’s function, they investigated mouse brains using optogenetics, a technique that allows neuroscientists to turn neurons off and on using pulses of light. By playing with the various serotonin pathways in the CA1 region of the hippocampus, they could get a better understanding of what each of them was doing.
They found that if serotonin release was increased, neuronal communication in CA1 became stronger; this had the effect of improving the mice’s spatial memory. Conversely, when serotonin release was artificially blocked, spatial memory was impaired.
This showed that serotonin release in the CA1 region could boost memory but also showed that memory formation is dependent on this pathway. Their findings are published in the journal Neuron.
Boosting Aging Memory: Serotonin Receptors
There are a number of serotonin receptor types. Identification of a specific class of serotonin receptor involved in memory, was the goal. When serotonin is released from within the hippocampus during learning, memory of the learned event is strengthened and retained long-term.
Scientists at Columbia University Irving Medical Center in New York City, NY, are at the forefront of this research. Led by Catia M. Teixeira, Ph.D., and Zev B. Rosen, Ph.D., they focused their latest project on serotonin release in the hippocampus and its impact on memory.
These researchers hit upon the specific serotonin receptor. As Teixeira continues, “We found that systemic modulation of 5-HT4 receptor function with drugs enhanced memory formation.”
Boosting Aging Memory: Study Results
This finding supports earlier work that also identified a role for the 5-HT4 receptor in memory. Also, a recent study conducted on healthy human volunteers found that the density of 5-HT4 receptors (how many are available to bind to serotonin) in the hippocampus predicted performance on a verbal learning test.
Because most people’s cognitive ability and memory declines with age, understanding the exact mechanisms behind memory storage and retrieval could have important implications.
If a drug could be designed to improve the serotonergic activity at 5-HT4 receptors in the CA1 region of the hippocampus, it could help people stay mentally sharp well into old age.