Abstract

Individual neurons have an elaborate architecture. These cells receive electrical and chemical signals over their extensive dendritic fields and send action potentials along axons that often branch before reaching their targets. Electrical recordings usually reveal information about the response in only one location in the cell and indicate little about the complexity of intracellular molecular signaling. Imaging techniques have been developed that can reveal aspects of the spatial heterogeneity of the neuron’s behavior. Many of these techniques take advantage of fluorescent molecules that have been designed to change their emission intensity when the concentration of different ions or small molecules in their environment changes. Sensors for Ca²⁺ and Na+ are popular and indicators for Cl" and cAMP have been developed. These indicators can be injected into individual living neurons in the brain or in a piece of the brain. They spread throughout the cell and their fluorescence can be detected with sensitive cameras. High-speed movies of the fluorescence changes correspond to dynamical changes in ion concentration in different parts of the neuron. Typical imaging devices are cooled scientific grade CCD cameras and confocal microscopes.

© 2002 Optical Society of America