A new study by UCLA neuroscience researchers is helping to clear up the mystery of exactly how and where memories are stored. The study showed that the current mainstream hypothesis that memories are stored in the nerve synapses is incorrect, but exactly where memories are stored in the neuron remains unknown.
The researchers point out that this discovery has major implications as it opens up the possibility that the memories of Alzheimer’s patients might be able to be recovered.
The study findings were published recently in eLife, a well-known online science journal.
Statement from Professor David Glanz
“Long-term memory is not stored at the synapse,” noted David Glanzman, a senior author of the study, and a UCLA professor of integrative biology and physiology and neurobiology. “That’s a radical idea, but that’s where the evidence leads. The nervous system appears to be able to regenerate lost synaptic connections. If you can restore the synaptic connections, the memory will come back. It won’t be easy, but I believe it’s possible.”
Details on the memory study
Glanzman’s team studied a type of marine snail (Aplysia) to get a better understanding of the animal’s learning and memory. The snail has a defensive response that protects its gill from harm, and the researchers were especially interested in the gill withdrawal reflex and the sensory and the neurons that produce it.
The researchers performed a series of tests to determine how memories were transmitted and stored. One surprising result was that memories that were thought to have been erased came back when synaptic connections were restored.
“That suggests that the memory is not in the synapses but somewhere else,” Glanzman pointed out. “We think it’s in the nucleus of the neurons. We haven’t proved that, though.”
This new study obviously has significant implications for people with Alzheimer’s disease. It means that although the disease is known to destroy synapses in the brain, it’s possible the memories are still stored in neurons and can be recovered if the synapses are regrown.
“As long as the neurons are still alive, the memory will still be there, which means you may be able to recover some of the lost memories in the early stages of Alzheimer’s,” Glanzman said.
Glanzman pointed out that in the later stages of Alzheimer’s disease, neurons actually die, which almost certainly means that the memories are permanently lost.