Cortical and subcortical control during chewing: an fMRI study

cortical and subcortical structures. Currently, the subcortical activations, during chewing, has been little investigated in literature. The present fMRI study aimed to evaluate the activation of cortical mastication areas and subcortical structures during chewing deliberately and nondeliberately with soft and hard boluses. Methods: Eight volunteers healthy subjects, with normal occlusion between 22 and 36 years of age were selected for the study. A unique high-resolution structural image and functional echoplanar images were acquired per run on a 3 T scanner during mastication of a soft bolus and a hard bolus. Results: In all subjects, gum-chewing was associated with significant increases in the BOLD signal in various regions of the brain. During the deliberately and nondeliberately chewing a BOLD increase was shown bilaterally in the following structures: primary sensorimotor cortex, the Broadmann areas 3, 6, 10, 13, 20, 21, 22, 27, 28, 32, 36, 37, 38 and also the caudate nucleus, putamen, pallidum, amygdala, thalamus and cerebellum, the corpus callosum and the hippocampus. Conclusions: The involvement of cortical and subcortical areas and structures, during chewing, is very complex. A deeper understanding of the motor control neurophysiology of mastication is important to understand the brain network involving motor control and cognitive processes.