For a number of years the topic of amnesia has been the topic of debate in the neuroscience community as to whether or not memories cannot be recalled because the cells are damaged and cannot be recovered or stored, or if the memories remain but are simply blocked. Well scientists may have just made a breakthrough on this topic when they recovered memories in the brains of mice. In the study published on Thursday 26th of May in the US journal Science the memories of mice were retrieved through the use of blue light pulsates to stimulate “memory engrams”. Memory engrams being the neurons that are activated as memories are created, are activated in everyday life, through images, sounds, taste and one of the most powerful triggers being smell. However for the study scientists attached a protein to these neurons that allowed them to be activated through the use of light, ruling out the other stimuli for the purpose of this study to prove:
“Amnesia is a problem of retrieval impairment” – Susumu Tonegawa MIT
The test went like so, the mice were placed in a chamber where an electric shock was administered to the feet of the mice, eliciting a freezing response. Half of the mice were given a compound called anisomycin as this was done; this compound prevents the strengthening of synapses, synapses being the structures that allow neurons to communicate with each other. Upon being returned to the chamber where the mice were given the shock, the mice who didn’t receive the anisomycin exhibited the same freezing-from-fear action as before, whereas the mice who were given the synapse blockers didn’t, clearing having forgotten it had ever happened. Now that it was established that the mice could not retrieve the memories of the pain the scientists activated the neurons the were involved in the foot shocking using to blue light pulses, which strengthened the synapses. Once this was done the treated mice would exhibit the same freeze-motions as their untreated counterparts, even as they were introduced into different cages.
The findings “will stimulate future research on the biology of memory and its clinical restoration,” Tonegawa stated.