Abstract

Investigation of signal transmission in brain requires to reproduce/observe physiological events that occur on a wide range of spatiotemporal scales, from e.g. the localized brief (μs) transient associated with a single (sub micron) synaptic event to the complex arithmetic that dendrites use in integrating (μs-ms) multiple localized synaptic inputs (several micrometer a part). Light microscopy is a fundamental tool in neuroscience offering a sensitive non invasive approach of probing and mimicking such brain complexity. In particular, we demonstrated that an effective way of covering a broad range of signaling patterns is to control light excitation by the engineering of optical wave -fronts obtained by phase modulation solely. Based on this approach, we present a novel microscope configuration that incorporates a nematic liquid crystal spatial light modulator to generate single photon holographic patterns and we show that, for large illumination area, holographic illumination enables to achieve a significantly improved axial resolution relative to Gaussian illumination. This microscope can produce illumination spots of variable size and number and patterns shaped to precisely match user-defined elements in a specimen.

© 2009 IEEE