Lateralization of Cortical Function in Swallowing: A Functional MR Imaging Study

BACKGROUND AND PURPOSE: While functional MR imaging and other techniques have contributed to our knowledge of functional brain localization, these methods have not been extensively applied to the complex and incompletely understood task of swallowing. We used functional MR imaging to investigate motor cortex activity during swallowing in healthy human adults. METHODS: Eight subjects were imaged on a 1.5-T MR system using blood oxygen level– dependent contrast mechanisms. Subjects performed three swallowing tasks and a finger-tap-ping task. Areas of activation in the cortex and subcortical areas were tabulated, and a later-ality index, defined as LI 5 [Ss left 2 Ss right]/[Ss left 1 Ss right] 3 100, was computed for the three tasks. RESULTS: Activation was observed in the primary motor and sensory cortices, motor pro-cessing and association areas, and subcortical sites. This activity was dominant for one hemi-sphere with left hemispheric dominance more prevalent among the subjects. Right hemispheric dominance, however, showed stronger lateralization than the left hemisphere. CONCLUSION: Our data indicate that specific sites in the motor cortex and other cortica