Often times, when pulling an all night study session, it seems
the information students "cram" into their brains is only
temporary knowledge. The same instance is seen in those who prepare
for a morning presentation the night before. But why is that?
In hopes of finding an answer to that question, researchers at
the University of Houston were recently awarded two grants totaling
over $2 million from the National Institutes of Health (NIH) to
continue investigating memory formation and the impact of the biological
clock on learning and memory. It has been previously discovered
that the brain's biological (or circadian) clock affects natural
body cycles, such as sleep, wakefulness, metabolic rate and body
temperature; however, research involving sea snails suggested the
circadian clock might also regulate the formation of memory during
the night.
Sea Snail Studies
With one of the grants provided, researchers at UH plan to continue
their studies based on data that reveals the circadian clock alters
several forms of long-term memory in sea snails. The results of
the studies showed:
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Sea snails form long-term memory when trained during the day
but not when they are trained at night.
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Short-term memory of the same behaviors is formed similarly
during the day and night, proving the circadian clock shuts
down the molecular circuit (in the neural circuit in the brain)
at a particular time of night, prohibiting the occurrence of
long-term memory.
Moreover, with the funds provided with the second grant, researchers
plan to focus on the transmitter substance glutamate -- involved in
memory formation -- in sea snails in order to understand the change
that takes place in the brain that enables people to remember.
Memory happens at places in the brain known as synapses (where
cells "communication" with each other through the release
of chemicals, or transmitter substances). Yet, for transmitters
to work effectively they must be cleared away once they are released
so others can subsequently act. Reuptake systems are the mechanisms
responsible for getting rid of transmitters. Further, thanks to
previous studies, researchers know:
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The molecules that act as the brain's cleaning crew during
learning and memory formation, glutamate transport molecules,
increase once the long-term memory-forming process begins.
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Memory lapses occur when deficiencies in glutamate transporters
affect the strength of connections among the neurons linked
to memory.
Researchers hope their findings will not only help people deal
with temporary memory lapses, such as misplacing car keys, but also
shed light on neurodegenerative diseases such as dementia and Alzheimer's.
Science
Blog February 28, 2005