Neuromagnetic detection of the laryngeal area: Sensory-evoked fields to air-puff stimulation

• Published in: NeuroImage (Orlando, Fla.) Vol. 88; pp. 162 - 169
• Main Authors: Miyaji, Hideaki, Hironaga, Naruhito, Umezaki, Toshiro, Hagiwara, Koichi, Shigeto, Hiroshi, Sawatsubashi, Motohiro, Tobimatsu, Shozo, Komune, Shizuo
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.03.2014; Elsevier; Elsevier Limited
• Subjects: Adult; Afferent Pathways - physiology; Air-puff stimulation; Biological and medical sciences; Dysphagia; Evoked Potentials, Somatosensory - physiology; Female; Fundamental and applied biological sciences. Psychology; Humans; Laryngeal sensory-evoked magnetic fields; Laryngeal somatic area; Larynx; Larynx - physiology; Magnetic fields; Magnetoencephalography; Magnetoencephalography - methods; Male; Minimum norm estimate; Physical Stimulation; Somatosensory Cortex - physiology; Studies; Vertebrates: nervous system and sense organs; Young Adult; Laryngeal somatic area; Laryngeal sensory-evoked magnetic fields; Air-puff stimulation; Minimum norm estimate; Magnetoencephalography; Evoked magnetic field; Stimulation
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2013.11.008

The sensory projections from the oral cavity, pharynx, and larynx are crucial in assuring safe deglutition, coughing, breathing, and voice production/speaking. Although several studies using neuroimaging techniques have demonstrated cortical activation related to pharyngeal and laryngeal functions, little is known regarding sensory projections from the laryngeal area to the somatosensory cortex. The purpose of this study was to establish the cortical activity evoked by somatic air-puff stimulation at the laryngeal mucosa using magnetoencephalography. Twelve healthy volunteers were trained to inhibit swallowing in response to air stimuli delivered to the larynx. Minimum norm estimates was performed on the laryngeal somatosensory evoked fields (LSEFs) to best differentiate the target activations from non-task-related activations. Evoked magnetic fields were recorded with acceptable reproducibility in the left hemisphere, with a peak latency of approximately 100ms in 10 subjects. Peak activation was estimated at the caudolateral region of the primary somatosensory area (S1). These results establish the ability to detect LSEFs with an acceptable reproducibility within a single subject and among subjects. These results also suggest the existence of laryngeal somatic afferent input to the caudolateral region of S1 in human. Our findings indicate that further investigation in this area is needed, and should focus on laryngeal lateralization, swallowing, and speech processing. •Magnetoencephalography detected somatic laryngeal responses to air-puff stimulation.•Body motion video monitoring with feedback to the subjects improved the S/N ratio.•Laryngeal somatic area is located in the caudolateral primary somatosensory cortex.