Movie S4.

Glutamate uncaging by UV light pulse is confined to the uncaging site. The fluorescence displayed by neurons transfected with iGluSnFr (expressed in the neuronal cell surface) was recorded at 40x magnification with a water 1.2 N.A. lens. The white arrow in the movie indicates the uncaging site, near a dendrite and far from the soma. A rainbow scale was used to show the fluorescence intensity of the glutamate sensor (blue: low values; red: high values). The fluorescence was recorded from ROIs placed at the dendrite or the soma. The black arrows indicate the times of glutamate uncaging by the sequential application of UV laser pulses of increasing intensity (0.1 V, 0.5 V and 1.0 V). The sampling time was 50 ms.