Development of a novel confocal microscope for functional recording of fast neuronal activity

Currently available recording methods limit the study of fast neuronal signaling by forcing a tradeoff between spatial and temporal resolution. Fortunately, advanced optical imaging techniques can be used to overcome this limitation. Specifically, we are developing confocal microscopy schemes that allow multisite recordings of neuron function in live brain tissue with high spatial and temporal resolution. The first scheme that is currently being investigated involves the use of a digital micromirror device (DMD) to implement the light paths necessary for high-speed confocal imaging: addressable point illumination and spatial filtering via addressable point detection. The second scheme involves the use of acousto-optic deflectors (AODs) in the illumination path to increase the excitation intensity, along with the DMD or an addressable CMOS imager as the spatial filter in the detection path. Calculations of the signal-to-noise ratios and operating parameters of the three devices indicate that we will be able to study both calcium concentration and fast membrane potential changes at several sites within the dendritic tree of a neuron.