I always thought of memory being like a filing cabinet. A memory is created and you file it away. When you want to return to it you look for a particular label and you find the specific memory you are in search of. This analogy as it turns out is completely wrong. Memory is more creative than that. Like a sculpture, parts of your memory get chopped or levelled and we add our own imagination to it. One of the first experiments that proved that memory was a tangible thing was a goldfish experiment.
A drug, Anisomycin was applied into a goldfish tank. The drug made the goldfish unable to learn and was amnesia-inducing by preventing the formation of specific proteins necessary to form memories. This finding suggested that memory was a tangible thing and has a physical trace in your brain made from proteins. The experiment that really changed the field was an experiment where a rat is put into a box, a sound is made and after that sound the rat is given a tiny shock in its head. The shock initiates neurons to be built between one brain cell and another (a sound brain cell to a shock brain cell). Thus, forming a memory structure. The next time the rat hears the sound it freezes since its memory is telling it a shock will follow. But if you give the rat an amnesia drug and then carry out the sound-shock experiment, the “memory” connections or structures never form, and rat never remembers.
But what if the drug was just causing brain damage and was not specific to memories?
Scientists then trained the rats to be afraid of two different tones, and then paired the drug to only one tone. Low and behold only the drug-paired tone memory was lost in the rats. The rats still had the freeze response to the second tone to which they received no drug. The implications here are incredible. Imagine being able to forgot your bad memories, for instance war veterans who suffer from post traumatic stress disorder. And incredible, these experiments have been done!
Critics might say that to delete someone’s memory is like changing that person. However that amnesia drug only works when a memory is being created. So if you can destroy a memory when it’s being made for the first time and when you are remembering it, it means you are actually re-creating your memory every time you think about it or even re-imagining the moment thus constantly changing the memory!
The writer is a Ph.D. in Molecular Genetics and Geno-mics and is working on skin cancer at Novartis