A novel multisite confocal system for rapid Ca imaging from submicron structures in brain slices.

In brain slices, resolving fast Ca fluorescence signals from submicron structures is typically achieved using 2-photon or confocal scanning microscopy, an approach that limits the number of scanned points. The novel multiplexing confocal system presented here overcomes this limitation. This system is based on a fast spinning disk, a multimode diode laser and a novel high-resolution CMOS camera.

In Vivo Voltage-Sensitive Dye Imaging of Mammalian Cortex Using "Blue" Dyes.

Optical recording of membrane potential allows simultaneous measurements to be taken from many different locations in the nervous system. This is important in studies of the nervous system in which simultaneous activity can occur at the regional, cellular, and subcellular levels. New "blue" dyes, developed by Amiram Grinvald's group, are a great advance for in vivo voltage-sensitive dye imaging of mammalian cortex.

Voltage-Sensitive Dye Imaging of Population Signals in Brain Slices.

In a bright-field measurement from a vertebrate brain stained by superfusing a solution of the dye over the surface, each pixel in a camera receives light from a substantial number (thousands) of neurons and neuronal processes (population signals). Because of scattering and out-of-focus light, this will be true even if the pixel size corresponds to a small area of the brain. In this situation, the voltage-sensitive dye signal will be a population average of the change in membrane potential of all of these neurons and processes.

Wide-field and two-photon imaging of brain activity with voltage- and calcium-sensitive dyes.

This chapter presents three examples of imaging brain activity with voltage- or calcium-sensitive dyes. Because experimental measurements are limited by low sensitivity, the chapter then discusses the methodological aspects that are critical for optimal signal-to-noise ratio. Two of the examples use wide-field (1-photon) imaging and the third uses two-photon scanning microscopy.