Is it possible to restore memory to people who have lost it due to amnesia or even, going further, to patients with Alzheimer’s disease? These possibilities were entirely unlikely, until now . A team of scientists led by Nobel laureate Susumu Tonegawa has managed to advance this goal by successfully returning memories lost due to amnesia to a group of laboratory mice.
In the experiment, using optogenetics, a technique born from genomics and optics that enables various groups of neurons to be activated and deactivated by light in order to study them, the scientists induced experimental amnesia in a group of mice (using anisomycin) to be able to verify if the memories disappear or remain hidden in our brain. It had already been achieved before to erase memories, so why not to recover them?
Thus, the mice were exposed to a situation that caused them fear (genetically marking the responsible neurons to allow their visualization and reactivation). Later, they got them to forget about the bad experience. Then, they managed to get the mice to recall the situation that caused them fear, confirming that memories are not lost, but that forgotten memory fragments can be recovered through the activation of memory “engrams” , biochemical and structural changes that are keys in the formation of a memory in neural circuits. These changes are what determine and modify its “strength”, to allow us, or not, to remember.
“Our conclusion is that in retrograde amnesia, memories of the past cannot be erased , but could simply be inaccessible. These results provide an impressive insight into the fleeting nature of memories, and will stimulate future research on the biology of memory and its restoration in clinical practice, ”explains Tonegawa.
The research has been published in the journal Science .
