July 25, 2013
New Puzzle Piece In How Brain Chemicals Affect Memory
April Flowers for redOrbit.com - Your Universe Online
New insight into the mechanism by which the brain uses chemical messengers may lead to a better understanding of memory preservation. A team of researchers, led by Trevor Hamilton of Grant MacEwan University and Bill Colmers of the University of Alberta, believes the findings may contribute to Alzheimer's disease research.
Their results were published in the Journal of Neuroscience and concern a chemical messenger called neuropeptide Y (NPY). NPY has been linked to neurological and mood disorders as diverse as obesity, epilepsy and anxiety.
Using electrical and chemical signals, different regions of the brain communicate with each other with long and short messages. The brain reacts to longer messages with calcium ions.
When brain cells receive long and short messages within milliseconds of one another, they begin to behave differently. This reaction is known as neuroplasticity and it is the cell-level basis for learning. With repeated incoming messages, the junction that allows them to pass from one cell to another will become more or less effective at sending signals. Hamilton and Colmers, who both work in the Centre for Neuroscience at the U of A, discovered NPY decreased the effectiveness of signal transmission in nerve cells in the neocortex area of the brain throughout a number of repetitions. In the absence of NPY, the brain cell automatically fires a longer message in response to the original signals it received.
"If you pair a short message with a calcium influx in these cells, it actually causes forgetting. When NPY is released, it prevents those neurons from forgetting that bit of memory so it sticks around longer," said Colmers, professor of pharmacology and neuroscience.
"This work will help with the overall understanding of memory formation and may contribute to Alzheimer's disease research," Hamilton added.
The researchers were surprised by the interaction between NPY and the neocortex. In a 2010 study, Hamilton and Colmers investigated the interaction of NPY and the hippocampus, the part of the brain that forms memories. The actions in both brain regions were identical, but the consequences were not. In the hippocampus, repetition of the NPY messages actually improved the effectiveness of the brain cell junction.
"If you don't understand how something works in the first place, how are you going to fix it?" Colmers remarked on the future medical potential of the research. Colmers and Hamilton both emphasized that, although exciting, more research is needed before these results can be translated into preventative and therapeutic tools.