The tongue is a complex muscular organ that is critical for oro-motor behaviors such as swallowing, breathing, speaking and chewing. The astonishing complexity and precision of the voluntary movements performed by the tongue depend upon the coordination of intrinsic (origin and insertion within the body of the tongue) and extrinsic (attached to bone and inserted into the base of tongue) tongue muscles. Until recently, almost all studies of lingual muscle function whether in speech, respiration or deglutition have concerned themselves with the study of whole muscle electromyographic (EMG) activities. Recently, we characterized respiratory-related tongue muscle and motor unit activities in healthy human subjects as a function of sleep/wake and in slow volitional movements. The results of this work provided de novo insights into lingual motor function and a platform from which to begin studies aimed at identifying how tongue muscles are controlled in more complex volitional behaviors. The current application builds thematically on previous work by the PI and yet departs from previous investigations in incorporating critical elements of the speech production process. Specifically, we propose to examine tongue muscle and motor unit activities and the potential for these activities to be modulated by inputs arising in the respiratory, phonatory (laryngeal) and/or supralaryngeal (oral- articulatory) subsystems. Understanding muscle and MU activities as a function of these influences separately and when successively overlaid is a logical first-step toward understanding how tongue muscle and motor unit activities are modulated in the more complex volitional behavior that is human speech production.

Public Health Relevance

The human tongue is perhaps one of the most complex, challenging, and least understood of all motor systems. This application outlines a plan to identify the fundamental processes by which the central nervous system controls tongue movement for speech.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC009587-05
Application #
8526446
Study Section
Motor Function, Speech and Rehabilitation Study Section (MFSR)
Program Officer
Shekim, Lana O
Project Start
2009-09-25
Project End
2014-08-31
Budget Start
2013-09-01
Budget End
2014-08-31
Support Year
5
Fiscal Year
2013
Total Cost
$332,728
Indirect Cost
$102,715
Name
University of Arizona
Department
Physiology
Type
Schools of Medicine
DUNS #
806345617
City
Tucson
State
AZ
Country
United States
Zip Code
85721
Walls, Clinton E; Laine, Christopher M; Kidder, Ian J et al. (2013) Human hypoglossal motor unit activities in exercise. J Physiol 591:3579-90
Laine, Christopher M; Nickerson, Laura A; Bailey, E Fiona (2012) Cortical entrainment of human hypoglossal motor unit activities. J Neurophysiol 107:493-9