The headline from the research is that selected memories can be erased and, at the same time, leaving other, less emotive memories intact. The research has focused on snail neurons only so far (this is with a marine snail called Aplysia). Despite the start involving the relatively small creature, the Columbia University Medical Center scientists behind the study think that those memories which trigger anxiety and post-traumatic stress disorder can, one day, be ‘erased’; importantly this would be without affecting normal memory of past events. What’s also interesting about the study is that different types of memories stored in the same neuron could be selectively erased.
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The research has established that when an traumatic event occurs this leads to multiple memories becoming encoded. This multiple storage includes memories of any incidental information present when the event occurs. The consequence is that when a traumatic experience occurs, the storage of such incidental information can trigger anxiety attacks some time after the event has occurred. Drawing on an example, Professor Samuel Schacher, who led the research, says: “The example I like to give is, if you are walking in a high-crime area and you take a shortcut through a dark alley and get mugged, and then you happen to see a mailbox nearby, you might get really nervous when you want to mail something later on.”
The research into the snail involved stimulating two sensory neurons, which were connected to a single motor neuron; here, one sensory neuron was stimulated to induce an associative memory and the other was stimulated to induce a non-associative memory. Detailed analysis the showed each increase in the strength of each connection, when produced by the different stimuli, was controlled by a different form of a protein called Protein Kinase M (PKM). These proteins were: one calledPKM Apl III, for associative synaptic memory; and another termed PKM Apl I, for non-associative memory. It was later found each memory could be erased, and importantly without affecting the other. This was through blocking one of the two PKM molecules.
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The findings will probably useful in understanding human memory because all vertebrates have similar versions of the Aplysia PKM proteins. The research is obviously at a very early stage; nevertheless the researchers think it is the stepping stone to the development of a drug that could eliminate selected ‘unpleasant’ memories.
The research has been published in the journal Current Biology, in a paper titled “Selective Erasure of Distinct Forms of Long-Term Synaptic Plasticity Underlying Different Forms of Memory in the Same Postsynaptic Neuron.”
