A window on promoting memory

Dr. John McLean, Basic Medical Science, (L) and Dr. Carolyn Harley, Psychology.

There are cellular pathways that may be able to be manipulated in order to improve learning and even provide ways of enhancing memory. It's quite a tall order, but Dr. John McLean, Basic Medical Science, and Dr. Carolyn Harley, Psychology, are excited about a new collaborative project to examine the critical events underlying learning.

The key to their research is smell. Dr. McLean has spent most of his career researching the olfactory bulb, a part of the brain that receives input from receptors in the nose and relays it to the olfactory nerve and then into the brain. Most importantly, the olfactory bulb is connected to feeling and memory.

That connection is central to the research taking place at Memorial, recently funded by the Canadian Institutes of Health Research for the next five years. “We're just putting the finishing touches on a set of data that shows a new kind of signaling that has never been shown before to be critical to memory,” explained Dr. Harley.

Dr. McLean added, “When you are learning something for the first time this signaling path is important.”

Using rat pups, the researchers have found that changing the time the pup is exposed to a smell changes how long it remembers the smell. “In one trial we found that by linking a smell with mother care or a drug substitute for mother care you get a memory in the young rat that lasts 24 hours,” said Dr. Harley. “If you repeat that over several days you get a memory that lasts a lifetime. This is a window on memory – once you understand what signals start memory, next you can understand how the brain changes to make memory.”

The key to studying this behavioural learning model is to investigate how certain brain neurotransmitters interact to produce learning. Specifically, Drs. McLean and Harley will be looking at norepinephrine, which they believe to be the reward signal for the learning, and serotonin, which makes it easier for the learning to occur.

Dr. McLean has already shown there is a specific cellular protein, pCREB, which is critically important in causing memories to form. “In this project we will determine what cellular mechanisms lead to pCREB production and determine how these pathways within cells may actually be manipulated to improve learning.”

Dr. Harley is excited about the long-term implications of their research. “Our studies may lead to developments in treating developmental learning disorders or lead to an understanding of memory which could provide memory enhancement approaches in young and aged adults.”

She added that it has already been shown that smell influences memory formation in humans. “I was recently at a conference on newborn human babies where research was presented showing that if a baby is given a pad of lemon smell next to the breast when nursing, that child, at two years of age, will prefer to take a bottle of water that has a lemon smell on the cover versus one that doesn't.”