Chapter 2. Prehension

482 THE GRASPING HAND
and grasping, 178-86
and performance accuracy, 199-200
peripheral, 178, 179-84, 180f. 181f
and preshaping of hand, 185-86, 186f
Visualmap, 118, I19
Visual perturbations
definition, 157
effects of, 159-66
and reaction time, 167
VITE. Vector Integration to Endpoint
model (VITE)
Volar grasp, 2Ot, 370t. 372f. 374,376
Volume, perception of, 231,233t. 234
W
Watch, winding, 28,272t
WATSMART system, for measuring velocity,
12.5.
151,155,178
Weight, in neural networks, 385,393, 394
Weight, of object
and deceleration of movement during
grasping, 155
and force plication for lifting,
234-3y 235f, 247,249
and kinematic landmarks, 154,155
perception of, 76,230,231,232,233t.
234
and role of visual information, 155
and sensory information during lifting,
253
and timing of movement, 155-56
and transport while grasping, 269-70
and wrist velocity, 155
Wrap grasp, 19t, 25,26f, 371t, 374
Wrench
space quality measure, 274
system, 236f. 237-39
wrist
degrees of freedom, 353
joints, 362t
movement, control by brain, 175
movement descriptions, 357f
muscles, 256,362t
optimal angle for prehension, 101
orientation in power grasp, 23,24f
orientation in precision grasp, 24f
in perturbation studies, 157-58. 16Of
posture in power vs precision grasp,
26364
skeletal stmcture, 352f. 353f
spatial path of, 129
velocity profiles during grasping, 49-51,
50f, 51,52f, 129,155
Writing, as dynamic hand movement, 272t
Writing grasp, '27,375. & External
precision grasp
(Letters after page numbers: fdigure; n=footnote; t-table.)