Functional Imaging, Neurophysiology, and the Resting State of the Human Brain

In this chapter, the physiological underpinnings of functional imaging signals and their significance for a more complete understanding of functional imaging studies are described. The physiological basis of brain functional imaging studies is related to a remarkable relationship between local brain blood. flow, metabolism, and cellular function. When cell function changes, blood. flow and metabolism change as well, making it possible for brain imaging to monitor local changes in cellular actively with great. fidelity. Recent advances in our understanding of brain energy consumption at "rest" are beginning to inform us about the nature of ongoing brain activity and how such local changes are to be considered in relation to it. In this context, the physiological basis for understanding imaging activations versus so-called deactivations will also be discussed.