Chapter 2. Prehension

Instructed grasp, 173
Intensity, of wrench, 239
Intent, and phases of prehension, 60-61
Interdigital latero-lateral grasp, 29
Interdigital step gras 19t, 28,272t. 371t
Intermediate grasp, Eb
Intermediate ridges, 209
Internal forces, 239, 265,268t, 273.274
Internal precision grasp, 2Ot, 28f, 30,36,
371t, 376,380
Interoceptors, 11 1
Interphalangeal joints, mechanoreceptors,
226,227f
Intrinsic object prT.rties
and activation o wsuomotor channels, 53
and activation of wrist and fingers, 143
defhtion, 51.53.76
and grasping. 330,33 1
speed of perception, 77-79
Inverse kinematic problem, 117n
Isotrc~y, 332
J
Jacobian matrix, 240,241
Jerk
definition, 1 1511
'minimum jerk model', 115
Jiggling, and weight perception, 230
Jomts
of hand, 352f. 353f
receptors, 226,228
torques
and fingertip force, 240-42
generating, 138-41
trajectories (of fingers), 131-34
r limb, 351-59,352f, 353f.
Of "T 54-58t, 360-64t
K
Keratinocyte differentiation, definition, 207
Key pinch, 2Ot, 262,263t. 37Ot
Kinematic profiles. Kinematics
Of arm and hand, in grasping, 141-46
artifical and natural hand, 15Of
computing
hand trajectory and muscle
activation, 136f
inverse kinematics of sequence of
actions, 132f
enclosing, as guarded motion, 191-94,
193f
and grasp mntml by CNS. 174-78
and grasp types, 166-74,168f, 17Of, 172f
joint level trajectories, 131-34
joint torques, 138-41
movement time, in grasping and pointing,
149f
muscle level commands, 135-38
with pad opposition
Subject Index 471
using central vision, 182f
using normal vision, 180f, 1 82f
using peripheral vision, 18Of
palm-focused model of gras ing. 194-%
and perturbation studies, 15&6.158f,
1m. 164f
under restricted sensory conditions,
17847.1 SOf, 182f
for setting up opposition space, 187-91,
286f
task requirements and object properties,
16-56
velocity
20 unit distance movement (VlTE
model), 13Of
deceleration phase, 147f
symmetric vs asymmetric, 123-31
wrist
and aperture-. 143f
tangential, 124f
Kinematics. gee also Acceleration of
movement; A rture; Asymmetric
velocity prozs; Deceleration of
movement; Jerk; Kinematic profiles;
Symmetric velocity profiles; Velocity
deffition, 1on
invariances, 145
landmarks, definition, 144
and object properties, 155
and object weight, 154,155
Of pad opp~~itiOn, 171-72
of palm Opposition, 171-72
of perturbation studies, 157-66
problems, 117x1
Kinetics. 1011. jee als~ Force application;
Torques
L
Lag time
and object properties in perturbation
studies, 165, 166
between signal and movement, 70.71
LAMA programming language, 66,67
Langer's lines, of skin, 206
Lateral horn of cord, and sweating, 218
Lateral motion, and perception of texture,
23 1,232f. 233t
Lateral pinch gras , l8f, 19t. 2Ot, 21,
28-29,35,33!, 37Ot. 371~ 372,
372f. 374,375,376
Lateral rotation (movement), 358
Leaky integrator model, of neural networks,
384-85.400
Leaming phase, of a neural network, 95,96f.
see also Supervised leaming
Length, of object, perception of, 229
Lid, screwing, as grasped object, 27
Lifting
and force application, 234.235% 254f
(Letters after page numbers: f=figure; n=fmtnote, t-table.)