Since the mid-1980s, there has been a rapid technological development in functional neuroimaging methods that have enabled the study of the human brain in vivo. Positron emission tomography (PET), single photon emission computed tomography (SPECT), functional magnetic resonance imaging (fMRI), magnetic resonance spectroscopy (MRS), and magnetoencephalography (MEG) now offer a diverse array of methods for studying metabolic and neurochemical brain development, as well as the neural systems subserving cognitive and emotional processes.

To provide a foundation for understanding these methods, particularly as applied to the study of brain development and deviance, Part 1 delineates the basic principles, advantages, and disadvantages of these modalities. Herscovitch and Ernst discuss the nuclear medicine techniques of PET and SPECT (Chapter 1) and Morris and colleagues discuss PET methods used to map receptors (Chapter 2). Eden and Zeffiro then describe the recent emergence of fMRI as a technique that can be used with neurophysiologic and neurocognitive probes to define neural circuits and determine their integrity in childhood disorders (Chapter 3). Yurgelun-Todd and Renshaw in Chapter 4 discuss advances in MRSfor the study of brain chemistry and the evolution of this technique into a brain mapping technique. Finally, in Chapter 5, Rojas and colleagues describe MEG, a technique with superior temporal resolution that directly measures neuronal electrical activity.

This diversity of functional imaging methods provides the means for mapping a variety of important brain maturational processes.