Neuromagnetic detection of the laryngeal area: Sensory-evoked fields to air-puff stimulation.
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.
Department of Otorhinolaryngology, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Japan; Department of Otorhinolaryngology, Yuaikai Oda Regional Medical Center, Japan. Electronic address: miyajih@qent.med.kyushu-u.ac.jp.
Hideaki
H
Miyaji
Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Japan.
Naruhito
N
Hironaga
Department of Otorhinolaryngology, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Japan.
Toshiro
T
Umezaki
Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Japan.
Koichi
K
Hagiwara
Division of Epilepsy and Sleep Center, Fukuoka Sanno Hospital, Japan.
Hiroshi
H
Shigeto
Department of Otorhinolaryngology, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Japan.
Motohiro
M
Sawatsubashi
Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Japan.
Shozo
S
Tobimatsu
Department of Otorhinolaryngology, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Japan.
Shizuo
S
Komune
D000328:Adult; D000344:Afferent Pathways / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D007830:Larynx / Q000502:physiology*; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D010812:Physical Stimulation; D013003:Somatosensory Cortex / Q000502:physiology*; D055815:Young Adult
Air-puff stimulation; Laryngeal sensory-evoked magnetic fields; Laryngeal somatic area; Magnetoencephalography; Minimum norm estimate