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