High-speed confocal laser scanning microscopy using acousto-optic deflectors and a digital micromirror device

Neurons are known to possess active computational properties. To investigate these properties, it is desirable to study the electrical and chemical properties not only at a living neuron's cell body, but also at many sites within its dendritic arborization. However, currently available recording techniques force a tradeoff between spatial and temporal resolution. To overcome these limitations, we have developed a confocal microscope that can make multisite optical recordings at an effective frame rate that is sufficient to measure fast neuronal events, such as action potentials, that occur on a timescale of milliseconds. We accomplished this by combining acousto-optic deflectors for addressable point illumination with a digital micromirror device for addressable point detection. After developing a registration algorithm to ensure synchronicity between point illumination and point detection, we used light-scattering test preparations to demonstrate that our system is capable of optical sectioning and therefore capable of imaging in living brain tissue. Furthermore, we have shown that fluorescence changes can be monitored at an effective frame rate of 25 kHz.