The long term goal of this project is to understand how finger muscles produce individuated finger movements--those in which one or more fingers are moved without moving the others. Though each finger often is assumed to be moved by its own muscles, the extrinsic muscles that provide most of the flexing and extending power typically send tendons to multiple fingers. This anatomic fact presents a paradox: contractions of these multitendoned muscles should move multiple fingers simultaneously. Individuated flexion and extension of the fingers are hypothesized to be possible because: i) functional subdivisions within some multitendoned muscles may apply tension relatively selectively to some of the muscle's tendons, and ii) the forces produced by different multitendoned muscles may combine such that the net forces on each finger cause one digit to move while other digits are held still. The proposed studies specifically aim to address the following 6 questions: 1) Does each neuromuscular compartment in multitendoned finger muscles distribute tension to more than one tendon? 2) Do single motor units in these muscles distribute tension to multiple tendons? 3) Do mechanical interconnections between a muscle's tendons passively distribute tension to multiple fingers? 4) Do single motor units in human finger muscles act on multiple fingers? 5) Do humans co-contract several multitendoned finger muscles to produce individuated movement of one finger while holding other fingers still? 6) Can the mechanical action of several multitendoned muscles combine to move one finger while holding the other fingers still? These studies will result in an improved basic understanding of how multitendoned finger muscles function, which can translate into: i) production of useful finger movements by functional electrical stimulation of these muscles in patients with brain or spinal cord injury, ii) more accurate botulinum toxin injections for treatment of the hand's focal dystonias, and iii) more appropriate tendon transfers for reconstruction of a useful hand in patients debilitated by forearm trauma. Moreover, results of the proposed studies of muscles will have broad implications for understanding how finger movements are controlled by the central nervous system.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS036341-03
Application #
2892244
Study Section
Neurology B Subcommittee 2 (NEUB)
Program Officer
Chen, Daofen
Project Start
1997-09-08
Project End
2001-05-31
Budget Start
1999-06-01
Budget End
2001-05-31
Support Year
3
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Rochester
Department
Neurology
Type
Schools of Dentistry
DUNS #
208469486
City
Rochester
State
NY
Country
United States
Zip Code
14627