Alzheimer's Patients Could Reclaim Lost Memories, Snail Study

If you are losing your memory in the first stage of Alzheimer's disease, just remember that you may even be able to get back your memories that are lost, according to indianexpress.com.

An exciting new study has found that your long-term memories do not need to be stored in synapses, which are the spaces or links between the brain cell neurons. Although Alzheimer's destroys the synapses, the nervous system can regenerate these lost synaptic connections, says David Glanzman, senior author of the study, and a University of California-Los Angeles professor. Just restoring the synaptic connections can restore the memories too.

The research team came to its conclusions by studying Aplysia, which is a type of marine snail. The snail's withdrawal reflex was increased when its tail was given a few light electrical shocks. It enabled the release of the hormone serotonin in the snail's central nervous system. "Long-term memory is a function of the growth of new synaptic connections caused by the serotonin," says Glanzman.

Even as long-term memories are created, new proteins leading to new synapses are also formed. However, if the process is disrupted, the proteins would not be formed, nor would the long-term memories be created.

Glanzman explains the process, according to kurzweilai.com. He points out that if you train an animal on something, but do not allow it to produce proteins immediately after that and test it 24 hours later, you find that the animal will not remember it. However, if you train an animal, wait for 24 hours, and then inject a "protein synthesis inhibitor in its brain", the animal's memory would be quite good even 24 hours later. 

Hence, after the formation of a memory, if you prevent protein synthesis for a short while, then you find that it will not impact long-term memory. This would be true in the case of the Aplysia as well as in human brains. Even after an accident or concussion, even an aged person would be able to remember earlier memories.

One thing, therefore, is clear---there is no fixed system of pattern regarding the synapses that stay and those which disappear. Memory, therefore, is not stored in synapses.