TEDTalks : Gero Miesenboeck reengineers a brain - Gero Miesenboeck (2010)

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In the quest to map the brain, many scientists have attempted the incredibly daunting task of recording the activity of each neuron. Gero Miesenboeck works backward -- manipulating specific neurons to figure out exactly what they do, through a series of stunning experiments that reengineer the way fruit flies percieve light.