|Trent Professor's Pivotal Findings on Spatial Memory to be Published in Prestigious Journal Nature Neuroscience|
Animal study shows memories of familiar environments can survive after brain damage that results in severe amnesia
SUNDAY, FEBRUARY 20, 2005 AT 1:00 P.M. ET
It's a snail-shaped formation in the medial-temporal lobe of the brain and it's long been thought to be the storage and retrieval bin for our memories of spaces and places. But the hippocampus, thanks to the work of Trent University Professor Gordon Winocur, will now have to share credit with other parts of the brain for the functions of spatial memory.
So important is the discovery made by Professor Winocur and his team of researchers, that one of the world's leading neuroscience publications, Nature Neuroscience, will publish his paper on the results of the three-year study in March 2005. Professor Winocur is a leading researcher in Trent University's Department of Psychology and a senior scientist at the Rotman Research Institute at the Baycrest Centre for Geriatric Care,
In basic terms, what Prof. Winocur has shown is that spatial memory is not housed in a single part of the brain, but rather in different places at varying levels of detail. The hippocampus remains the lead player in the processing of new memories and the storage of detailed memory, but Prof. Winocur's experiment proves that the brain keeps a back-up copy, a more generalized version of spatial memory stored outside of the hippocampus. This back-up memory stored elsewhere is schematic in detail as opposed to the richly detailed memory in the hippocampus.
Hints that the brain was backing up information outside of the hippocampus have shown themselves in two known human cases discovered in Toronto and California. Two individuals who suffered brain damage, specifically to the hippocampus, were unable to learn new spatial information, but somehow were able to recall how to get to places they had been in the past. The problem was how to prove the phenomenon in a laboratory setting with non-human subjects.
To do so, Prof. Winocur and his team, including Trent graduates Melanie Sekeres and Stuart Fogel, set out to create a "rat village," a setting that would mimic a human neighbourhood of sorts. In various corners of the village, they placed reward items such as water and food that would attract the rats repeatedly. Once the rats had a chance to learn their surroundings, a selected group was given lesions to the hippocampus.
The results of the study reflected exactly the same experience as that of the two brain-damaged individuals. The rats with lesions to the hippocampus were as able as normal rats to find their way to various areas of the village they had previously learned about. Creating new memories by learning new locations, however, was impossible.
The significance of this discovery will change the way we understand memory and the brain and create a new platform from which to research brain plasticity.
"What's important is that everyone talks about a model that shows same results in the lab as in humans," says Prof. Winocur of the results. "It's always a challenge to demonstrate clinical observations in a lab setting."
The results have implications for new possibilities in cognitive rehabilitation as well, says Prof. Winocur. "By showing that certain crucial memories remain intact in brain areas other than the hippocampus, we can begin to develop programs that emphasize strategies to learn and remember information in new and different ways for individuals with brain damage."
Memory loss is one of the most frequent complaints among older people and the hippocampus is one of the first areas of the brain to decline with age. It is also the major side effect for those who suffer from stroke and neurodegenerative diseases like Alzheimer's. The hippocampus is also vulnerable to toxic elements and is the most likely part of the brain to be affected by exposure to toxins.
Publication of the research paper in Nature Neuroscience will ensure that the research findings will reach a large audience of clinicians and neuroscientists. "It's also an example of the groundbreaking research going on right here at Trent University," says Prof. Winocur.
Other collaborators on the paper were Dr. Morris Moscovitch and Dr. Shayna Rosenbaum. The study was funded by the Natural Sciences and Engineering Research Council and the Canadian Institutes for Health Research.
For more information:
Professor Gordon Winocur can be reached at Trent University at (416) 785-2500 ext. 3592.
Marilyn Burns, director of communications at Trent University (705) 748-1303.