Flashcards in Lecture 22: Locomotion Deck (44)
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1
Locomotion
an activity leading to a change in the location of the body in external space.
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Examples of locomotion
walking, running, hopping, swimming, flying, crawling, etc.
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Important characteristics of locomotion
-velocity
-stride length
-relation between the support and swing phases
-relative timing of the extremities (gait)
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Two different views of Locomotion
1. Motor Programming
2. Dynamic Systems
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Motor Programming
Central Pattern Generator: hypothetical neural structure that generates a neural activity, activity is transformed into rhythmic muscle activity, leading to rhythmic behavior
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Dynamic Systems
rhythmicity of locomotion is caused by interaction of neural activity and the periphery
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Early Views of Locomotion
1. Sherrington
2. Brown
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Sherrington
-Locomotion was a pattern produced by alternating reflex responses.
-Voluntary movement is a result of modulating reflexes
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Brown
Rhythmic motor pattern of locomotion was produced by a special neural network(CPG) that could produce activity even in the absence of reflexes
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A CPG is
a hypothetical structure in the central nervous system that can generate patterned (rhythmical) activity
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CPG can be driven by _______ as well as by peripheral information
"Higher" centers
-Both sources of information can lead to gait changes
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CPG involves ______ types of cells.
three
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CPG: Cells of two types act on each other and ________.
suppress each other's activity.
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CPG: Cells either fatigue quickly or turn off after a brief period of activity, allowing _____.
the other group to be released from inhibition and take over.
Cycle continues until an external influence turns off both groups of cells.
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Neurons of the 3rd group provide ___________.
input that can both excite and suppress the cells of the 1st two groups
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Problems w/CPG: ______ higher center
Undefined
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Problems w/CPG: ______ input could change the pattern of gait activity
Peripheral
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Problems w/CPG: Difficult to determine if changes in ____ are produced by higher center or peripheral input.
gait
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Problems w/CPG: Many important variable lack _____.
a good definition
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Problems w/CPG: This drove the development of _____.
dynamic systems approach
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Stimulating _____ of cats led to rhythmic moments of the cat's limbs
reticular formation
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Different levels of stimulation could _________ locomotion.
slow down or speed up
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Locomotor Strip is in the ____.
upper cervical region of the spinal cord
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________ of certain brain areas can induce locomotion
Electrical Stimulation
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______ changes with the strength of the stimulation.
Gait
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Locomotion and gait changed can also be induced by ______.
treadmill motion and by intraspinal drugs
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________ locomotion can be see.
Fictive
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Graham Brown v. Sherrington: The spinal is likely to contain one, two, to even four _________.
Central Pattern Generators
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Graham Brown v. Sherrington: A CPG can be driven by _____.
descending and ascending signals.
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Graham Brown v. Sherrington: It does not necessarily require _____.
either signal
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Graham Brown v. Sherrington: It can produce ____.
different gaits
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Dynamic Systems Approach is a system for:
movement production, including the central neural structures, effectors and the connections with the CNS, and the environmental forces and sources of sensory information, can be modeled with complex, non-linear equations.
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______ better explains issues of stability (particularly in M/L direction)
Dynamic Systems Approach
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Dynamic Systems Approach succeeds in describing ______.
inter-limb and inter-joint coordination
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DSA: The equations developed by this approach can describe these rather ____.
complex changes in behavior.
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Motor Programming lacks ___.
coordination, all details of coordination are delegated by the ultimate controller
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Dynamic Systems: coordination can emerge without supreme problem solved, but it lacks_____.
control
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What happen when there is a combination of motor programming and dynamic systems?
All elements are linked and there is an upper neural structure that can send descending signals.
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In M/L direction, COP shifts _______.
towards the stepping foot and then shifts back toward supporting foot.
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In A/P direction, COP shifts ______.
backward
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Corrective stumbling reaction occurs during _______.
locomotion
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Corrective stumbling reaction can be induced by _____.
a mechanical stimulus to the foot.
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Corrective stumbling reaction represents a _______.
complex pattern of EMG changes
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