The goal of the proposal is to explore the strategies used by the central nervous system when manipulating hand- held objects. Recently we developed a new mathematical method of inverse optimization - the 'Analytic Inverse Optimization'(ANIO) method -that allows for reconstructing unknown cost functions (CF) from experimental recordings (Terekhov et al. 2010). The first line of research will deal with the further development of the method and its application to human prehension. Experiment 1-A will explore whether all performers use CFs of the same class. Experiment 1-B will test whether the ANIO method yields estimates of the CFs that are reproducible over protracted periods of time. Experiment 1-C will explore the dependence of the CF class of functions on the number of fingers involved in the task. Experiment 1-D will address interaction between the optimization and variability in multi-finger prehension. The second line of research is based on previous results obtained in our lab and is intended to test the following hypotheses: Experiment 2-A will test the additivity hypothesis: suppose that the digit forces are affected by factors A, B, C, etc. The hypothesis assumes that the effects of the neural commands associated with the above factors are additive. In statistical terms it means that the effects of the factors are significant while their interactions are not. Experiment 2B extends the additivity hypothesis to the complex dynamic tasks. We expect to find that the pattern of grasping force changes as a sum of the effects of two commands associated with the movements along and normal to grasp direction, respectively. Experiment 2C will deal with testing a template control hypothesis according to which for every given combination of the object geometry and local friction the performers select a digit force pattern ('template') and then scale the digit forces with the load force. Experiment 2- D will consist of two parts in which effects of one finger fatigue or fatigue of all fingers will be explored. The goal is to test whether the fatigued finger exerts the same %% of its current maximal force as it did prior to fatigue. Essentially, the experiment will explore the 'robustness'of prehension control, using local fatigue as a perturbation tool. Under 'robustness'we understand ability to perform a task when performance potential of one of the contributing elements is diminished.

Public Health Relevance

The research has three potential fields of applications: clinics, prosthetics, and robotics. In clinics, the research will have implications for improving diagnostic tools and rehabilitation procedures. In prosthetics and robotics, it will lead to construction of efficient hand prostheses and 'artificial hands'.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR048563-11
Application #
8513259
Study Section
Special Emphasis Panel (ZRG1-MOSS-C (02))
Program Officer
Panagis, James S
Project Start
2002-04-01
Project End
2015-08-31
Budget Start
2013-09-01
Budget End
2014-08-31
Support Year
11
Fiscal Year
2013
Total Cost
$310,436
Indirect Cost
$96,686
Name
Pennsylvania State University
Department
Miscellaneous
Type
Schools of Allied Health Profes
DUNS #
003403953
City
University Park
State
PA
Country
United States
Zip Code
16802
Parsa, Behnoosh; Terekhov, Alexander; Zatsiorsky, Vladimir M et al. (2017) Optimality and stability of intentional and unintentional actions: I. Origins of drifts in performance. Exp Brain Res 235:481-496
Singh, Tarkeshwar; Ambike, Satyajit (2017) A soft-contact model for computing safety margins in human prehension. Hum Mov Sci 55:307-314
Falaki, Ali; Huang, Xuemei; Lewis, Mechelle M et al. (2017) Dopaminergic modulation of multi-muscle synergies in postural tasks performed by patients with Parkinson's disease. J Electromyogr Kinesiol 33:20-26
Parsa, Behnoosh; Zatsiorsky, Vladimir M; Latash, Mark L (2017) Optimality and stability of intentional and unintentional actions: II. Motor equivalence and structure of variance. Exp Brain Res 235:457-470
Zhou, Tao; Falaki, Ali; Latash, Mark L (2016) Unintentional movements induced by sequential transient perturbations in a multi-joint positional task. Hum Mov Sci 46:1-9
Latash, Mark L (2016) Biomechanics as a window into the neural control of movement. J Hum Kinet 52:7-20
Ambike, Satyajit; Mattos, Daniela; Zatsiorsky, Vladimir M et al. (2016) Unsteady steady-states: central causes of unintentional force drift. Exp Brain Res 234:3597-3611
Lewis, Mechelle M; Lee, Eun-Young; Jo, Hang Jin et al. (2016) Synergy as a new and sensitive marker of basal ganglia dysfunction: A study of asymptomatic welders. Neurotoxicology 56:76-85
Jo, Hang Jin; Ambike, Satyajit; Lewis, Mechelle M et al. (2016) Finger force changes in the absence of visual feedback in patients with Parkinson's disease. Clin Neurophysiol 127:684-692
Parsa, Behnoosh; Ambike, Satyajit; Terekhov, Alexander et al. (2016) Analytical Inverse Optimization in Two-Hand Prehensile Tasks. J Mot Behav 48:424-34

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