"The more I understand about the nature of synaptic change during learning," he said, "the more amazed I am by how complicated it gets. Why does it have to be so complicated? Why can't serotonin just cause the presynaptic change all by itself? Why does it need this postsynaptic signal? There's a complicated dance taking place between the postsynaptic cell and the presynaptic cell."
This complex process may be the brain's way of preventing mistaken learning, according to Glanzman.
"Nature seems not to want your synapses to change very easily," he said. "To learn something, you have to produce fairly detailed cellular changes. It looks like you can't just change one side of the synapse if you want to have a long-term memory. You don't want long-term changes at synapses that are important for learning to occur easily. This is a way to minimize mistaken learning; it keeps synapses from changing for unimportant reasons. It's better than a lock-and-key relationship; you can put the key in, but you also have to have a code to get the key to turn to lock something in long-term memory."
For memories that last for weeks or longer, the presynaptic and postsynaptic cell have to talk to each other, Glanzman said, and "we're beginning to understand the chemical signals of the conversation."
It will take time, because memory is such a complicated phenomenon, but the research is progressing rapidly.
"Every day," he said, "we learn new, unexpected things."
Glanzman's research to understand learning and memory on a fundamental level has the potential to help with human brain disorders. His research may lead to such applications as developing interventions for people with memory-related disorders and reducing age-related memory loss.
|Contact: Stuart Wolpert|
University of California - Los Angeles