Neuroimaging studies of speech an overview of techniques and methodological approaches

Over the past two decades, there has been an explosion in the use of imaging technology to study the structure and function of the human brain. The purpose of this article is to explore how functional neuroimaging has been applied to the study of speech production. This article begins with a brief review of neuroimaging methods and limitations. Then, two approaches that can be used to study the brain areas that support speech production are illustrated. The first approach is based upon comparisons across different types of language production tasks; the second approach is based upon comparing the effects of different types of stimuli within a single task. Results obtained using these approaches will be used to dissociate the contributions of different brain regions involved in speech production. For example, evidence will be presented that Broca's area contributes to phonological encoding, whereas motor cortex, the supplementary motor area (SMA), and the cerebellum support phonetic encoding and articulation.

As a result of this activity, the participant will be able to describe basic methods for conducting a positron emission tomography study and a functional magnetic resonance imaging study. The participant will also be introduced to two approaches for fractionating the brain regions involved in speech production: (1) comparisons between tasks, and (2) manipulations of stimulus materials. Finally, the participant will be able to summarize a cognitive model of the components of speech production that will be introduced, and potential mappings between these components and particular brain regions will be discussed.