A team of scientists from the Center for Neurosciences at the University of California at Davis (USA) has managed to completely eliminate specific memories in mice using light , specifically using a technique called optogenetics, which is based on making light fall on neurons, among other living tissues, to control them.
For their experiment, the experts used genetically modified mice so that when their neurons were activated, they glowed with green fluorescence . In addition, these neurons expressed a protein that made it possible to deactivate nerve cells with light . Thus, they discovered which neurons were activated in the cerebral cortex and the hippocampus, since both coordinate the retrieval of episodic memories, when the mice learned and retrieved memories and, on the other hand, deactivate those neurons with light through a fiber optic cable.
Thanks to the green fluorescence, the scientists showed that they could specifically identify the cells that participate in learning and that these were reactivated when the recovery of what was learned was necessary. In the same way, by “turning off” those nerve cells in the hippocampus with light, they made the mice lose that memory . This hypothesis was confirmed after trying to deactivate other cells of the hippocampus different from those involved in learning, and verifying that memories were not affected in this case.
As explained in the journal Neuron Kazumasa Tanaka and Brian Wiltgen, leaders of the study, ” this empirically demonstrates for the first time that the cerebral cortex cannot store and retrieve memories by itself , but needs the help of the hippocampus.”
