Sensory stimulation activates both motor and sensory components of the swallowing system

Abstract

Volitional swallowing in humans involves the coordination of both brainstem and cerebral swallowing control regions. Peripheral sensory inputs are necessary for safe and efficient swallowing, and their importance to the patterned components of swallowing has been demonstrated. However, the role of sensory inputs to the cerebral system during volitional swallowing is less clear. We used four conditions applied during functional magnetic resonance imaging to differentiate between sensory, motor planning, and motor execution components for cerebral control of swallowing. Oral air pulse stimulation was used to examine the effect of sensory input, covert swallowing was used to engage motor planning for swallowing, and overt swallowing was used to activate the volitional swallowing system. Breath-holding was also included to determine whether its effects could account for the activation seen during overt swallowing. Oral air pulse stimulation, covert swallowing and overt swallowing all produced activation in the primary motor cortex, cingulate cortex, putamen and insula. Additional regions of the swallowing cerebral system that were activated by the oral air pulse stimulation condition included the primary and secondary somatosensory cortex and thalamus. Although air pulse stimulation was on the right side only, bilateral cerebral activation occurred. On the other hand, covert swallowing minimally activated sensory regions, but did activate the supplementary motor area and other motor regions. Breath-holding did not account for the activation during overt swallowing. The effectiveness of oral-sensory stimulation for engaging both sensory and motor components of the cerebral swallowing system demonstrates the importance of sensory input in cerebral swallowing control.

On the functional anatomy of the urge-for-action

“…Furthermore, increasing capsaicin levels leads to a reliable increase in estimates of this urge (Davenport, Sapienza, & Bolser, 2002). Similarly, in our own unpublished studies of the effects of oropharyngeal stimulation on the urge-to-swallow, we have found that oropharyngeal stimulation using pulses of air produces both an urge-to-swallow and overt swallowing (for similar findings, see also Lowell et al, 2008). More importantly, we have found that increasing the intensity of oropharyngeal stimulation leads to an increase in the strength of the perceived urge-to-swallow.…”

Orosensory contributions to dysphagia: a link between perception of sweet and sour taste and pharyngeal delay time

“…2006; Lowell et al. 2008); however, sensation from these structures is mediated by the glossopharyngeal nerve (CN IX), stimulation of which is already known to be able to elicit a swallow. In addition to afferent input from CN X and CN IX, the NTS receives sensory input from the oral tongue via fibers of the chorda tympani branch of the facial nerve (CN VII) for taste on the anterior two‐thirds of the tongue.…”

Ressonância magnética funcional e deglutição: revisão sistemática

“…Scientific articles were categorized specific features to the swallowing cortical representation (3,(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) . Research on elderly and patients with dysphagia underwent compared to control groups.…”