Midterm II Flashcards
(30 cards)
Reflex
stereotyped, involuntary, automatic and usually rapid response to stimuli
M1
monosynaptic stretch reflex contraction of stretched muscle within 30-50ms, important for posture, thousands can occur in parallel
M2
polysynaptic functional stretch reflex: contraction of muscle within 50-80ms, has at least one synapse in brain, more flexible
M3
RT response, all stages of IP, maximally flexible, triggered reaction, 150ms, non-voluntary, complex and coordinated
Dorsal stream
Specialized for movement control, involves entire visual field, non conscious, where/how of object directed, damage; action task
Optic flow
the movement/flow of patterns of light rays from the environment over a person’s retina, allowing person to detect motion, position and timing
Ventral stream
specialized for conscious identification, involves center of visual field, conscious, what of objects, damage; perception task
Which visual stream is crucial to movement planning
Ventral, integrating knowledge about objects with our current action goals
Motor program
a set of motor commands that is pre-structured at the executive level and that defines the essentials of a skilled action
Open loop
centrally determined, pre-structured commands sent to the effector system and executed without feedback
Open loop functioning
preplanned instructions specifying function, sequence and timing, once the program starts the system continues to completion without modification, no ability to detect and correct errors (*reflexes)
Open loop uses
For rapid discrete movements, in predictable and stable environments
Polit and Bizzi
Monkey’s performance does not significantly deteriorate with deafferentation - gross motor not affected
CPG
a centrally located control mechanism that produces mainly genetically defines, repetitive actions such as locomotion or chewing
Reflex-reversal phenomenon
a special case of reflex activity involving different responses to the same stimulus
GMP theory
A motor program that defines a pattern of movement rather than a specific movement; can change parameters to produce movement variations that meet different environmental demands
Invariant features
the characteristics of a movement that stay the same when the surface features of the movement change
Relative timing
a measure of the temporal structure of a movement, in which the ratios among the durations of various movement features are used to define the temporal pattern (fundamental timing structure)
Fitts law variables
Independent variables: amplitude and width
Dependent variable: movement time
Fitts law equation
MT ~ A/W and MT = a + b [Log2(2A/W)]
Index of Difficulty
[Log2(2A/W)]
Linear speed accuracy trade off variables
Independent variables: MT (reinforced FB) and A
Dependent variable: We = effective target width
Linear speed accuracy trade off
As A increases We increases, We ~ A/MT
Spatial accuracy
accuracy of rapid movements for which the spatial position of the movements endpoint is important to task performance
