Neurologists have discovered that memory restoration may be a near possibility. In a recent study, researchers from UCLA's department of Integrative Biology and Neurobiology found that memories are not stored in the synapses, as was once believed.
For many year, neuroscientists believed that memories were stored in the connections between cells of the brain, known commonly as "synapses". And as memory loss has become synonymous with Alzheimer's disease, known to destroy synapses, researchers correlated that memories too were destroyed in the process. However, with this groundbreaking discovery, neuroscientists believe now that memories are stored in the neurons themselves.
The team of researchers led by UCLA professor David Glanzman recognized the potential implications that this breakthrough discovery could have for the community suffering with Alzheimer's disease and decided to investigate it further. According to Glanzman, the study revealed that as long as the neurons are still alive, some memories can still be restored for patients suffering from the early stages of Alzheimer's. Though, he added that in the later stages of the disease when neurons atrophy and die, memories can no longer be restored.
"Long-term memory is not stored at the synapse," Glanzman says. "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."
After hypothesizing that memories are stored in the neurons themselves, the team of neurologists investigated the possibility of memory restoration by studying a unique species of marine snail known as "Aplysia". Particularly interested in the Aplysia's withdrawal reflex and the sensory and motor neurons that produce its unique defensive response, the researchers looked into how Aplysia is able to protect its gill from potential harm..
By giving mild electrical shocks on the snail's tail, the withdrawal reflex was enhanced. And according to the research team, the shocks caused the hormone serotonin to be released in the snail's nervous system. After a series of electric shocks, the enhancement lasted for days, indicating the response had been stored in the snail's long-term memory.
According to Glanzman, when the hormone serotonin was released, new synaptic connections grew and long-term memory restoration was a result of this growth. When long-term memories are formed , Glanzman added, the brain creates new proteins that are involved in making new synapses.
"If you train an animal on a task, inhibit its ability to produce proteins immediately after training, and then test it 24 hours later, the animal doesn't remember the training" Glanzman said. "However, if you train an animal, wait 24 hours, and then inject a protein synthesis inhibitor in its brain, the animal shows perfectly good memory 24 hours later."
"In other words, once memories are formed, if you temporarily disrupt protein synthesis, it doesn't affect long-term memory. That's true in the Aplysia and in human brains."
With this monumental breakthrough, scientists believe they have taken the first steps toward restoring lost memories, though only in the early stages of their degeneration.
