Improvements in the Optical Recording of Neuron Activity Using Voltage-Dependent Dyes

Abstract

Studies of the electrical activity and plasticity of neural networks, individual nerve cells, and their subcellular compartments are now impractical without using optical methods to visualize functional signals which allow electrical events to be recorded both in many neurons simultaneously and in individual dendrites and axons and provide for linking these data to precise morphological images. Use of voltage-sensitive dyes (VSD) is the only of the small number of currently available methods which combines high spatial resolution with the ability to record ultrafast signals (<0.1 msec) in real time with a high signal:noise ratio. Significant progress in applying VSD has been made in the last decade, particularly in analysis of the occurrence and encoding of electrical signals in dendrites and axons, and has resulted from improvements in the method associated with using the best dyes in combination with sequential improvements in apparatus and optical instruments. This has allowed the method to demonstrate its value and effectiveness and advance from purely technical areas to the arsenal of major equipment in the world’s leading laboratories working at the frontiers of cell biology and neurophysiology.