Imaging Somatosensory Cortex: Human Functional Magnetic Resonance Imaging (fMRI)

Abstract

Functional magnetic resonance imaging (fMRI) is a powerful tool for imaging somatosensory cortex, providing a means to non-invasively measure cortical activity in awake and behaving humans. Notably, this technique has permitted the homunculus—a hallmark of primary somatosensory cortex (S1) organization—to be examined with unprecedented detail. With the development of high-resolution fMRI (mostly at ultra-high field, 7 Tesla), it is now possible to investigate the finer topographic details of the sensory homunculus in almost any individual. Moreover, fMRI can be used to investigate other various bottom-up response properties as well as more top-down perceptual and cognitive processes (e.g., attention and prediction) across a wide range of experimental conditions. This chapter mainly focuses on tactile experiments, outlining a number of experimental paradigms and analysis techniques; practical and participant-specific difficulties are noted. Although we focus on fMRI for imaging primary somatosensory cortex, this technique can also be used to image cortical activity in other areas involved in somatosensory processing, such as secondary somatosensory cortex (S2), insular cortex, or the cerebellum.