This video shows the output of an experiment in which researchers selectively stimulated individual neurons in the mouse brain. Neuronal stimulation is indicated by a change in fluorescence; the panel on the left shows the change in fluorescence and the panel on the right shows the raw fluorescence. Red arrows point to the next cell to be stimulated; the arrow turns green when the holographic laser beam—used to stimulate the neuron—is turned on. Some neurons respond more strongly to the stimulation than others. (Video courtesy of the Adesnik laboratory, University of California, Berkeley)
