The Bailey Lab
Research conducted in the Bailey Lab has as its focus the voluntary and respiratory-related neuromuscular control of upper airway muscles. In particular, our interest is in the control of tongue musculature as a function of sleep and wakefulness, in response to respiratory-related sensory stimuli and simple volitional movements. Our experiments are designed to provide insights into the nervous system (efferent and afferent components) control of these upper airway muscles in human and non-human mammals. Our work combines behavioral, neurophysiological and computational approaches to the study of upper airway muscle activities. Our objective in conducting this work is to gain insight into the nervous system control of upper airway musculature and to establish a foundation for subsequent work that examines tongue muscle and motor unit activities in the performance of highly automated movements i.e., swallowing and speech. Current research in non-human mammals has as its focus the hypoglossal (XII) motoneuronal pool. Our interest is in characterizing XII MN anatomy and somatotopy. This work will serve as an important initial step for subsequent electrophysiologic studies in identified hypoglossal motoneurons in the very early post natal period.
Anatomy.
Unlike muscles of the limbs, the muscle of the upper airway, and more specifically the tongue, lack an internal bony skeleton. Thus the tongue is composed almost entirely of muscle. Four “intrinsic” muscle pairs are contained entirely within the tongue body (i.e., the inferior and superior longitudinalis, verticalis and transversus muscles). Four “extrinsic” muscle pairs have origins external to the tongue and terminations that decussate into the tongue body (i.e., the genioglossus, styloglossus, palatoglossus, and hyoglossus muscles). In humans, intrinsic tongue muscles interdigitate extensively throughout the body of the tongue. This interdigitation has severely limited the ability to record from individual intrinsic tongue muscles. By comparison the extrinsic tongue protrusor muscle, genioglossus (GG) is readily instrumented and accessible through the tissue under the chin. In human (and most non-human) mammals, the GG arises on the mandible anteriorly and then fans posteriorly inserting into the base of the tongue and into the body of the hyoid.
Support.
Our work is supported by National Institutes of Health Grants (NIDCD: K23 007597; RO1 009587; Challenge Grant EB 10915) and by UA Gift Fund 560040.
Anatomy.
Unlike muscles of the limbs, the muscle of the upper airway, and more specifically the tongue, lack an internal bony skeleton. Thus the tongue is composed almost entirely of muscle. Four “intrinsic” muscle pairs are contained entirely within the tongue body (i.e., the inferior and superior longitudinalis, verticalis and transversus muscles). Four “extrinsic” muscle pairs have origins external to the tongue and terminations that decussate into the tongue body (i.e., the genioglossus, styloglossus, palatoglossus, and hyoglossus muscles). In humans, intrinsic tongue muscles interdigitate extensively throughout the body of the tongue. This interdigitation has severely limited the ability to record from individual intrinsic tongue muscles. By comparison the extrinsic tongue protrusor muscle, genioglossus (GG) is readily instrumented and accessible through the tissue under the chin. In human (and most non-human) mammals, the GG arises on the mandible anteriorly and then fans posteriorly inserting into the base of the tongue and into the body of the hyoid.
Support.
Our work is supported by National Institutes of Health Grants (NIDCD: K23 007597; RO1 009587; Challenge Grant EB 10915) and by UA Gift Fund 560040.
