The purpose of this dissertation was to determine if the CNS produces relatively simple alterations in muscle activity to accomplish goal-directed reaching motions of the upper limb under a variety of movement conditions. / To this end, six subjects performed goal-directed arm movements in the horizontal plane. Two movement amplitudes (300 mm and 400 mm) were completed at a moderate speed (1050 mm/s) and as-fast-as possible. The speed and amplitude conditions were repeated for the 45$ sp circ$ and 90$ sp circ$ movement directions. Finally, each of the movement conditions mentioned thus far, were performed within the right and left sections of the work-space. Surface electro-myographic activity was recorded from the pectoralis major, posterior deltoid, biceps brachii short head, brachioradialis, triceps brachii long head, and triceps brachii lateral head. Motion recordings were obtained with a spatial imaging system that monitored the positions of infrared emitting diodes attached to the subject's upper arm and forearm-hand complex. / Several simplification schemes were found to be operative at the level of the electro-myogram. These include: (a) simple timing relationships for agonists between joints and agonist/antagonist intermuscle latencies within each joint; (b) tightly coupled timing between agonists within a single joint; (c) for a particular movement direction, the form and shape of EMG burst activity followed a strategy associated with modulation of pulse height and width; (d) the slope, duration, and onset were further affected by the direction of hand movement which resulted in the greatest RMS-EMG signal amplitude, changing in a predictable manner, and finally (e) there was tuning in which elbow muscles were activated earlier for goal-directed arm movements in the left area of the work-space.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.28748 |
| Date | January 1995 |
| Creators | Gabriel, David Abraham |
| Contributors | Hoshizaki, Thomas Blaine (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Physical Education.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001462691, proquestno: NN05706, Theses scanned by UMI/ProQuest. |
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