Chapter 2. Prehension

Chapter 7 - Opposition Space Phases 295
4. Temporal invariances can occur between transport and grasp
(Jeannerod, 1984).
5. Spatial invariances can occur between transport and grasp
(Wing & Fraser, 1983; Wing, Turton & Fraser, 1986).
6. The index of difficulty of the task affects the transport
component (Marteniuk et al., 1987).
7. Precision effects occur in deceleration (Marteniuk et al., 1987).
8. Preshaping is different from enclosing (Jeannerod, 1984;
Marteniuk et al., 1987).
9. Location of the object influences movement parameters
(Paulignan, MacKenzie, Marteniuk, & Jeannerod, 199 1).
10. Force-related object properties affect the transport component.
11. Task goals affect the transport component (Marteniuk et al.,
1987).
12. The posture chosen reflects perceived object properties and task
properties (Arbib et al., 1985; Jeannerod, 1981, 1984;
Marteniuk, Leavitt, MacKenzie, & Athenes, 1990).
13. Contact is avoided during preshaping.
14. The CNS transforms information between coordinate frames
(Georgopoulos et al., 1988).
15. A population vector for movement direction is computed in
motor cortex (Georgopoulos et al., 1988; Kettner et al., 1988,
Schwartz et al., 1988).
16. Muscles are tunable springs (Feldman, 1986).
17. Preshaping is getting fingers into right ballpark.
18. The first phase of orienting the palm is getting the hand into the
right ballpark of location and palm orientation.
19. An arm trajectory is computed in body coordinates from goal
location (Massone & Bizzi, 1989).
20. The CNS can compute inverse kinematic computations,
generating joint angles from goal locations, using an adaptive
constraint network (Jordan, 1988).
2 1. The CNS maintains internal models of dynamics and of inverse
dynamics for replacing feedback control with feedforward
control as movement is learned (Kawato et al., 1987).
22. Hand movement is a two-phase movement, and first phase is
feedforward, while second phase is feedback.
23. Reshape movement is occurring in a feedforward sense.
24. Orient palm is feedforward.
25. Sensory information is needed for preshaping (Jeannerod,
1986).
26. Peripheral vision is used for arm movements (Sivak, 1989).