A new study from the Montreal Neurological Institute and Hospital (The Neuro) of McGill University reveals that different patterns of training and learning lead to different types of memory formation.
A new study from the Montreal Neurological Institute and
Hospital (The Neuro) of McGill University reveals that different
patterns of training and learning lead to different types of memory
formation. The significance of the study, published in the Journal
of Neuroscience, is that it identifies the molecular differences
between spaced training (distributed over time) and massed training
(at very short intervals), shedding light on brain function and
guiding learning and training principles.
In every organism studied, results have shown that memory
formation is highly sensitive not only to the total amount of
training, but also to the pattern of trials used during training.
In particular, trials distributed over time are superior at
generating long-term memories than trials presented at very short
intervals.
“It is a well known psychological principle that learning is
better when training trials are spaced out than when given all
together,” says Dr. Wayne Sossin, neuroscientist at The Neuro and
lead investigator of the study. “However, there are very few, if
any studies that identify, at the molecular level, differences
between the two types of training.”
“In this study, using Aplysia, a type of mollusk often used as a
model of learning in which the difference between spaced and massed
training has been well established, we identify an event, the
activation of the enzyme called Protein kinase C Apl II (PKC Apl
II), which is very different under the two training paradigms and
could explain the differences in learning.
The process of strengthening communication between nerve cells
(neurons), called synaptic facilitation, represents learning and is
the basis of change in learning in Aplysia. This process is
controlled by the release of a neurotransmitter called serotonin.
Four to five spaced applications of serotonin generate long-term
changes in the strength of the synapse – the junction between two
neurons - but in this study lead to less activation of PKC Apl II.
This leads to stronger connections between neurons and therefore
increased learning and memory. In contrast, if the
application of serotonin is continuous, as would be the case in
massed learning/training, the researchers found that there was much
more activation of PKC Apl II, suggesting that activation of this
enzyme may block the mechanisms for generating long-term memory,
while retaining mechanisms for short-term memory.
This study shows that the enzyme PKC Apl II is regulated
differently by spaced versus massed applications of serotonin and
that the difference in activation of PKC Apl II can explain some of
the distinction between spaced and massed training.
This work is supported by the Canadian Institutes of Health
Research (CIHR).
About the Montreal Neurological Institute and
Hospital
Celebrating 75 years
The Montreal Neurological Institute and Hospital (The Neuro) is
a unique academic medical centre dedicated to neuroscience. The
Neuro is a research and teaching institute of McGill University and
forms the basis for the Neuroscience Mission of the McGill
University Health Centre. Founded in 1934 by the renowned Dr.
Wilder Penfield, The Neuro is recognized internationally for
integrating research, compassionate patient care and advanced
training, all key to advances in science and medicine. Neuro
researchers are world leaders in cellular and molecular
neuroscience, brain imaging, cognitive neuroscience and the study
and treatment of epilepsy, multiple sclerosis and neuromuscular
disorders. For more information, please visit www.mni.mcgill.ca.