By directly manipulating the activity of individual neurons, University of Oxford and University of Virginia scientists have given flies false memories of a bad experience, enabling scientists to now obtain a level of evidence about brain function that was impossible before.

To pinpoint the exact 12 neurons responsible for this memory among thousands in the fly brain, the researchers used a technique they developed called optogenetics, in which a simple flash of laser light is used to release caged molecules in selective neurons that then stimulate the activity of those neurons.

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