Scientists and educators alike have
long known that cramming is not an effective way to remember
things. With their latest findings, researchers at the RIKEN Brain
Science Institute in Japan, studying eye movement response in
trained mice, have elucidated the neurological mechanism explaining
why this is so.
Published in the Journal
of Neuroscience, their results suggest that protein synthesis
in the cerebellum plays a key role in memory consolidation,
shedding light on the fundamental neurological processes governing
how we remember.
The "spacing effect", first discovered over a century ago,
describes the observation that humans and animals are able to
remember things more effectively if learning is distributed over a
long period of time rather than performed all at once. The effect
is believed to be closely connected to the process of memory
consolidation, whereby short-term memories are stabilized into
long-term ones, yet the underlying neural mechanism involved has
long remained unclear.
To clarify this mechanism, the researchers developed a technique
based around the phenomenon of horizontal optokinetic response
(HOKR), a compensatory eye movement which can be used to quantify
the effects of motor learning. Studying HOKR in mice, they found
that the long-term effects of learning are strongly dependent on
whether training is performed all at once ("massed training"), or
in spaced intervals ("spaced training"): whereas gains incurred in
massed training disappeared within 24 hours, those gained in spaced
training were sustained longer (Fig. 1+2).
Earlier research suggested that this spacing effect is the product
of the transfer of the memory trace from the flocculus, a
cerebellar cortex region which connects to motor nuclei involved in
eye movement, to another brain region known as the vestibular
nuclei (Fig. 3). To verify this idea, the team administered local
anesthetic to the flocculus and studied its effect on learning.
While learning gains in mice that had undergone one hour of massed
training were eliminated, those in mice that had undergone the same
amount of training spaced out over a four hour period were
unaffected.
Explaining this observation, the researchers found that the spacing
effect was impaired when mice were infused with anisomycin and
actinomycin D, antibiotics which inhibit protein synthesis. This
final discovery suggests that proteins produced during training
play a key role in the formation of long-term memories, providing
for the first time a neurological explanation for the well-known
benefits of spaced learning - as well as a great excuse to take
more breaks.
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RIKEN: http://www.riken.jp/engn/
