Chapter 5 - Functional Neuroimaging of Speech Production

Abstract

The addition of neuroimaging techniques to language research has allowed independent evaluation of theories developed to explain the mechanisms responsible for this unique human activity. The rapid pace of technological advance in functional neuroimaging methods shows no signs of abating, as the limits to the ability to resolve neural activity on ever finer spatial and temporal scales have been more constrained by engineering and financial considerations than physical ones. During the relatively brief time that systems allowing efficient and noninvasive monitoring of brain activity have been widely available, investigators utilizing functional neuroimaging have relied on a series of related techniques. Most of these methods rely on the tight coupling between neuronal activity and regional cerebral blood flow first noted at the end of the 19th century, based on the observation that focal electrical cortical stimulation resulted in localized changes in cerebral hemodynamics. The first successful single photon emission computed tomography imaging system based on these phenomena utilized inhalation of radioactive 133Xe, which served as a relatively noninvasive marker for cerebral blood flow. The development of functional magnetic resonance imaging systems suitable for psychological studies provided a more convenient and completely noninvasive means to study perception, language, and action.