Neurological and musculo-skeletal diseases severely impair the complex coordination of finger motion and forces that characterizes our ability to grasp and manipulate objects. Knowledge of the physiological control mechanisms of prehension is essential for an understanding of the pathologies that affect hand function. The long-term objective of the present proposal is to characterize the normal patterns of muscle activation responsible for the control of grasping movements, in particular the strategies used by the nervous system to coordinate the large number of muscles of the hand. This objective will be pursued by studying the simultaneous activation of multiple hand muscles and the coordination of grip forces. The present proposal has three specific aims: to characterize the organization of hand muscle activity as a function of hand and wrist posture (Aim number 1); to determine whether motor unit synchronization is dependent on task constraints (object's size and center of mass location;
Aim number 2) and grip type (power vs. precision grip, and object shape;
Aim number 3). The proposed studies are based on the hypothesis, supported by previous work, that the coordination of multiple grip forces is based on synergies reducing the number of degrees of freedom that has to be controlled independently. We will determine how the activity of multiple hand muscles is coordinated as a function of finger/wrist posture and task constraints. Hand muscle activity will be measured by intramuscular electromyographic recording as (a) interference multi-unit EMG and (b) single motor unit activity. Contact forces exerted by each finger will be measured in three dimensions by force sensors. The issues examined by this basic research are relevant to efforts in rehabilitation and restoration of hand function.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR047301-03
Application #
6729957
Study Section
Special Emphasis Panel (ZRG1-GRM (01))
Program Officer
Panagis, James S
Project Start
2002-04-01
Project End
2006-03-31
Budget Start
2004-04-01
Budget End
2005-03-31
Support Year
3
Fiscal Year
2004
Total Cost
$145,015
Indirect Cost
Name
Arizona State University-Tempe Campus
Department
Other Health Professions
Type
Schools of Arts and Sciences
DUNS #
943360412
City
Tempe
State
AZ
Country
United States
Zip Code
85287
Jesunathadas, Mark; Laitano, Juan; Hamm, Thomas M et al. (2013) Across-muscle coherence is modulated as a function of wrist posture during two-digit grasping. Neurosci Lett 553:68-71
Chattopadhyay, Rita; Jesunathadas, Mark; Poston, Brach et al. (2012) A subject-independent method for automatically grading electromyographic features during a fatiguing contraction. IEEE Trans Biomed Eng 59:1749-57
Johnston, Jamie A; Bobich, Lisa R; Santello, Marco (2010) Coordination of intrinsic and extrinsic hand muscle activity as a function of wrist joint angle during two-digit grasping. Neurosci Lett 474:104-8
Johnston, Jamie A; Formicone, Gabriele; Hamm, Thomas M et al. (2010) Assessment of across-muscle coherence using multi-unit vs. single-unit recordings. Exp Brain Res 207:269-82
Danna-Dos Santos, Alessander; Poston, Brach; Jesunathadas, Mark et al. (2010) Influence of fatigue on hand muscle coordination and EMG-EMG coherence during three-digit grasping. J Neurophysiol 104:3576-87
Poston, Brach; Danna-Dos Santos, Alessander; Jesunathadas, Mark et al. (2010) Force-independent distribution of correlated neural inputs to hand muscles during three-digit grasping. J Neurophysiol 104:1141-54
Johnston, Jamie A; Winges, Sara A; Santello, Marco (2009) Neural control of hand muscles during prehension. Adv Exp Med Biol 629:577-96
Winges, Sara A; Johnston, Jamie A; Santello, Marco (2006) Muscle-pair specific distribution and grip-type modulation of neural common input to extrinsic digit flexors. J Neurophysiol 96:1258-66
Winges, Sara A; Santello, Marco (2005) From Single Motor Unit Activity to Multiple Grip Forces: Mini-review of Multi-digit Grasping. Integr Comp Biol 45:679-682
Johnston, Jamie A; Winges, Sara A; Santello, Marco (2005) Periodic modulation of motor-unit activity in extrinsic hand muscles during multidigit grasping. J Neurophysiol 94:206-18

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