Activation of Cerebellum and Basal Ganglia on Volitional Swallowing Detected by Functional Magnetic Resonance Imaging

Abstract

Although regions of the sensorimotor cortex, insula, and anterior cingulate gyrus are reported to be activated during swallowing, findings concerning contributions of the cerebellum and basal ganglia have been contradictory. We investigated cerebellar and basal ganglionic activation using functional magnetic resonance imaging (fMRI). In 11 subjects, single-shot gradient-echo echoplanar image volumes sensitive to BOLD contrast were acquired in block design fashion using an oblique orientation covering both cerebrum and cerebellum. Using statistical parametric mapping, regional activation upon swallowing was observed in the sensorimotor cortex, insula, cerebellum, putamen, globus pallidus, thalamus, anterior cingulate gyrus, supplementary motor area, superior temporal gyrus, and substancia nigra. The cerebellum was activated bilaterally, especially on the left; activation of the putamen and globus pallidus was also found bilaterally. Thus, volitional swallowing involves the cerebellum and basal ganglia as well as cortical structures. The method used was well tolerated by normal subjects and should also be applicable to patients with dysphagia.

Normal Swallowing and Functional Magnetic Resonance Imaging: A Systematic Review

“…Fourteen articles that used fMRI in healthy adults while swallowing were relevant and are detailed in Table 1 [ 41,[53][54][55][56][57][58][59][60][61][62][63][64][65].…”

“…However, the rest condition is often implied in fMRI studies. On the other hand, other studies clearly indicated that an "off" swallow [64] …”

“…These areas of focus include cortical [41,53,54,56,61,63], cortical and subcortical [55,57,59,60,62,65], lower brain stem and cervical spinal cord regions [58], and the cerebellum and basal ganglia [64].…”

“…Visual cues were provided using written instructions, drawings, or even flashlight [41,53,54,60,65] and auditory cues were typically instructions given by the investigator [64]. Some studies used subject selfinfusion of a water bolus as a swallow stimulus [55] or varied the stimulus depending on the task [57,58,[61][62][63] (i.e., saliva swallow used an audio cue and water swallow was initiated by water infusion).…”

“…In a block design, trials from each condition are grouped in time and a rest period is often incorporated (control or nulltask blocks) so that activity related to particular tasks can be measured [46]. Six studies used only block designs [41,58,[61][62][63][64] that incorporated activity (i.e., swallow, nonswallowing motor task) and rest intervals.The event-related (or single trial) design assumes that neural activity related to a particular task has a discrete interval that can be best captured when not restricted to predetermined or …”