Locomotion

Question 1

one might describe walking as

Answer 1

graceful falls followed by agile recovery of balance

Question 2

Essential requirements for walking behavior

Answer 2

Progression
Postural control
Adaptation

Question 3

CPGs are

Answer 3

the ensemble of spinal cord neural networks that generate locomotor bursts

Question 4

Corticospinal activity that drives gait synapses first on

Answer 4

interneurons and then the interneurons activate the CPGs

Question 5

Propriospinal axons/system - what are they

Answer 5

shorter axons that connect one CPG to another so that the arm knows what the leg is doing - it is a means of communication

Question 6

CPGs are ___ limb and ___ limb

Answer 6

within limbs and across limbs

allow for the rhythmic “flex/ext” motion to occur

Question 7

What drives the CPGs to turn on

Answer 7

Supraspinal sources

Question 8

Supraspinal regulation of walking ncludes what 3 functional systems

Answer 8

One activates the spinal locomotor system, initiates walking, controls speed
One refines motor pattern in response to feedback from the limbs
One critical for visual guidance of limbs

Question 9

What is involved in initiating walking and controlling speed

Answer 9

MLR
Subthalamic locomotor region
PPN

Question 10

MLR/PPN –>

Answer 10

RF - reticulospinal tract - LMNs and postural mm and also the CPGs

Question 11

When the BG is working well - and the direct pathway is facilitated what happens

Answer 11

locomotor region is turned on

excitation/activaton of reticulospinal and CPGs

Question 12

Motor cortex directly synapses on

Answer 12

interneuorns and can regulate CPG

Involved with adaptive gait, visual guidance

Question 13

What is the portion that refines motor pattern n response to feedback from the limbs

Answer 13

CBM!

Question 14

How does CBM refine motor pattern response to feedback from the limbs

Answer 14

Gets ascending proprioceptive info and the state of the CPG - cares about what is happening at the CPGs
Efferent copy from MI
error detection and correction
postural control

Question 15

Can someone with ataxia still step

Answer 15

Yes - they still have the locomotor pattern - they may not have as good of error detection and correction but the basic locomotor plan is still ther

Question 16

What areas are critical for visual guidance of limbs

Answer 16

Motor cortex

V1 - PPC - PMA - M1

Question 17

What areas are critical for visual guidance of limbs - motor cortex - critical for

Answer 17

visually guided movement

skilled walking

Question 18

What areas are critical for visual guidance of limbs - motor cortex - lesion in cat study showed

Answer 18

the cats could walk on smooth floor but could not step over obstacles or walk on the rungs of a horizontal ladder - they were missing the visuomotor coordination

Question 19

What areas are critical for visual guidance of limbs - V1, PPC, PMA, MI work by

Answer 19

adjusting our steps 2 to 3 steps in advance of the obstacle

visual scanning

Question 20

What areas are critical for visual guidance of limbs - PPC crticial role in

Answer 20

helping to plan adjustments, obstacle negotiation

Question 21

What areas are critical for visual guidance of limbs - PPC - lesion in cat study

Answer 21

misplaced their paws on approach and they could not adapt to obstacles

Question 22

What is important for the switch in CPGs to allow for reciprocating activity

Answer 22

Muscle spindle (1a) 
GTO (1b)

Question 23

In walking, GTOs when activated will

Answer 23

excite their own muscle and inhibit the antagonist

has to do with the load - will assist in walking up inclines

Question 24

If stimulate foot during early swing - you see

Answer 24

rapid flexion of the limb

Question 25

If stimulate foot during stance phase you see

Answer 25

excitation of the extensors

Question 26

Phase dependent reflex reversal is what

Answer 26

the same cutaneous stimulus can elicit different responses depending on the phase of the gait cycle the person is in