Study of marine snail leads to new insights into long-t...( UCLA cellular neuroscientists are pr...)

UCLA cellular neuroscientists are providing new insights into the mechanisms that underlie long-term memory research with the potential to treat long-term memory disorders.

"The more we know about how long-term memory is induced in the brain and how our memories are maintained in the brain, the more we are going to be able to treat long-term memory loss," said David Glanzman, UCLA professor of physiological science and neurobiology, whose new research appears June 19 in the early online edition of the journal Current Biology.

For 25 years, Glanzman has studied learning and memory in the marine snail Aplysia, which is substantially larger than its garden-variety counterpart and has approximately 20,000 neurons in its central nervous system; humans have approximately 1 trillion.

"All the things that we find in the snail, we eventually find in the mammalian brain," said Glanzman, who is helping to unravel the brain's mysteries. "Knowledge about learning and memory in Aplysia will inform us about the kinds of changes that take place in our brains when we learn."

During long-term memory, in the snail and in our brains, synaptic connections become stronger.

Scientists had thought that during learning in snails, the neurotransmitter serotonin binds to receptors on the presynaptic axon and, through a complicated process, causes the growth of new presynaptic axons. In Current Biology, Glanzman and his UCLA colleagues report that "the process is not actually initiated in the presynaptic axon, but that this presynaptic change is actually initiated in the postsynaptic neuron."

"Surprisingly, we're seeing that there is a specific presynaptic protein whose synthesis is actually regulated by postsynaptic calcium," Glanzman said. "What we think happens is when serotonin binds to receptors on the postsynaptic neuron, it causes an elevation of calcium within the postsynaptic neuron, and somehow this el
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