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Human Motor behaviour > Week 13 - A + B > Flashcards

Week 13 - A + B Flashcards

1
Q

what is meant byt he renshaw cell acts as a governor

A

they limti the activity of the MN

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2
Q

Bacteria causing tetanus relase tocxin that…

A

prevents release of glycine

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3
Q

what is the benefit of pre-synaptic inhibition

A

can inhibit the afferent without altering the MN, inhibit specif cpathway onto the MN

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4
Q

what 3c ontexts must we maintain our baalnce?

A

1) during quiet stanidn
2) unexpected perturabtion
3) during self-initiated movements

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5
Q

what is postural contro?

A

controlling body position in space o maintain stability and orientation

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6
Q

what is Centre of mass?

A

the location where all the mass of a body is concentrated

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7
Q

what is centre of gravity

A

vertical rojects of COM to ground

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8
Q

what is diff between COM and COG and COP

A

centre of mass is where eall mass of body is concentrated (5/9 of height)
COG is a vertical projection of the COM to ground and COP is th epoint of application of vertical ground raction force exrted on body

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9
Q

why is quiet standing not actually rly quiet

A

there is still some body sway due to physiological perturbation (HR< breathing, trmeor, muscle tone)

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10
Q

can our bodys maintin perfect equilibrium? what can they do?

A

cannot but can be stabilized - sway is inevitable but we can maximize stability so sway doesn’t cause us to fall

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11
Q

amount of sway is affected by the body’s ______

A

allignment
better allignment = less sway

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12
Q

a stable posture exists if …

A

the vertical line of action of the force of gravity passes through the whole body

when bod alligned with line of gracity
minimal neergy tomaintain balcne and maximal stability

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13
Q

generally a person has a stable posture as long as ..

A

line of action of COG is wihtn base of support

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14
Q

what 3 biomechanical factors affect stability

A

postural stability decreases if the base of support is reduced

psotural stbaility decrease if line of COG is closer to edge of base of supprot

postural stability decreases with increase in height of COM

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15
Q

what is the explratory mechanism?

A

standing balance requires constant sensory input to know where and how we are positioned in space

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16
Q

is sway exploratory? do we need swaY?

A

yes we do - in the absence of COM displacement (No sway) we actually drive ur body to sway (increase COP) - which allows us to gather the sensory info we need to balance

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17
Q

where does the drive to sway come from?

A

muscle activity used to sway during quiet standing has low coherence with cortical activity - primary is subcortically driven

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18
Q

Regarding postural stability, which of the following is not true?
A. Postural stability is reduced if base of support is narrower
B. Postural stability is reduced if the centre of gravity is further from the edge of the
base of support
Increased - keep COG away form base
C. Postural stability is reduced if the height of centre of mass is increased
D. All of the following is true

A

postural stability is icnreased id further from edge of base of support

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19
Q

is sway improtant and why

A

yes - it is an explroatory mechanism - improtnat for searching for sensory feedback

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20
Q

what are soem factors thaat affect posture?

A

medication, pain, aging, neurological disorders

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21
Q

true or false. Effective psotural control involves only the ability to generate and apply forces (COP) and activate appropraite msucles?

A

false - also involved whe ebody is in space and whta forces are acitng on the body

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22
Q

how is the contrubtion of sensory sytems assesed>

A

removing or altering sensory info available
using patient pop where sensory ingfo is absent or sitroed

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23
Q

what are the 2 common ways to assess involvement

A

Quiet stanidn (COM or COP)
external perturbation (reactive balnce)

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24
Q

what are the 3 main sources of peripheral inputs to detect teh body;s positiona ndmvoment relative to environnment?

A

vision, vesitbular, proprioception

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25
without visual inptu what happens to postural sway
30-40% psotural sway
26
what is the physical perturbtation of with vision what about visual
COM displacedment is greate forllwing linear movement of suraface with eyes perceiving a car moving ehn ur car is acutall mobing
27
waht does teh moving room apradigm illustrate?
that vision is involved in queiet stanidn
28
is vision involved in quiet standing abnd how do weknow
yes - we know because when we remove vision there is greater sway and greater movement of the COP/COM alter optic clfow tog ive the illsuipon taht a person is swaying in one direction --> they will mofe the COM isn the opposire direction
29
explain how the vestibular system plays a role in balance/sway?
head tilitn - COP increaises with head tils - tilting ehad down or up while walking incrases sway
30
reduced sensory feedback from legs and feet elad to ___ sway
icnreased sway - propriocception
31
what w aspects ecplain the role o fpropricoeption in standing balance/sway?
vibration to msucle, cooling feet/topical anesthetic loss of lower limb somatosensory input inputs (hypothermia, ischaamic block) leads to increased sway
32
is proprioception involved i quiet standing? how do we know?
yes - if we remove/alter propricocepotion --> greter sway, indicated by grater movement of COP/COP - if propriocpeive feedback added back with finger --> decrease movment of COp/COM
33
what is the differnc ein COP/COM diaplcement (sway) in blind indivudals vs those with their eyes clsoed?
Blind paritcipants had smaller COP< COM displacement comapred to sighted with eyes clsoed
34
what information can substitute for the loss of vesitbular function
cutaneous sensory info
35
can de-afferent patients compensate if you lose all SS info
it's very hard for them to have balanced control but can stand with vision and conscious control
36
what happens to standing balance with aging - what leads to this?
reduce muscle strength, and sensory function (vision, vestibular, proprioception - increase postural sway - reason to perturbation slower with greater muscle activity
37
Which of the following is/are evidence that proves proprioception is important for standing balance? A) Vibration of a muscle involved in a postural task leads to an illusion of change in postural sway B) Greater movement of COP with head tilts C) Ischemic or hypothermic block of the lower limbs leads to reduced sway D) Lightly touching a support railing increases postural sway E) A and C COM = Centre of mass COP = Centre of pressure
Vibration of a muscle involved in a postural task leads to an illusion of change in postural sway
38
what are the three components of standing baalnce and the three fucntional goals?
quiet standin - maintain antigravity posture unexpected perutbation - raeactive balance voluntary self-intiated movment - anticipatory postural
39
How does the postural control system maintain a desired orientation and stability if there is an external perturbation (i.e., decelerating bus
in resposne to destabilizng extenral force/operturbation - CNS repssons to info recived duringa nd afte rmovemnt and attempts to restore stability
40
what is msucle synergy
uscles work together (in synergy) to achieve the task; in case of reactive balance, it occurs without voluntary control
41
in reactive balance muscular synergy occurs with voluntary control. true or false.
False - involvuntary control
42
what are the two main responses in reactive balance
ankle strategy hip strategy
43
what is the diff between ankle and hips tartegy inr active balance?
ankle - sistal to proximal hip - proximal to distal activate oppostie msucles
44
what are 4 reactive balance strategies?
ankle- rrpate about ankle only - boy sratih hip - rotate about hip only - torso staright suspesnory - crouch down step strategy - take a step due to COM moving outside limits of stability
45
small balance perturbations usually invole the ____ stategy large involve ?
ankle lerge involve hip strategy
46
if support is a narrow beam do you us hio or anke strategy
hip
47
what problem with reactive balance Does cerebellar disorder patients have?
Hypermetria - voluntary movements have problems scaling responses - moving body parts beyond the intended goal
48
Which of the following is/are true regarding reactive balance strategies? A) Consist of voluntary muscle synergies to react to a balance perturbation B) A suspensory strategy is the same as voluntarily reducing the height of COM to become more stable C) Ankle strategies are more likely to be used on a narrow support surface, so as to not overreact to a perturbation and fall D) Ankle strategies activate muscles in a distal-to-proximal pattern tokeep the body upright E) All of the above are true
) Ankle strategies activate muscles in a distal-to-proximal pattern tokeep the body upright
49
what is locomotion
controled rhytmic act of moving oru body from one place to another repeated cycles of movement
50
what two phases can walking be broken into?
stance - 60% - start with heel contact swing - 40% - start with toe off
51
what is double support and when does it occur in thes tep cuy
It occurs in the first and last 10% of the stance phase - it is when both feet are on the ground at the same time
52
in both walking and running, legsmove in _____
antiphase - move in oppostide diracations not in synch
53
what is plantigrade and is it involved in running or walking?
when the whole sole of the foot is on the ground - in running and wlaking
54
what is the H reflex?
stretch reflex evoked by electrical stimulation of I an afferent - bypassing activation of spindle receptors
55
does presynaptic inhibtion act directly on Alpha MN
no - on i a afferent
56
what is digitigrade and is it involved in running walking or both
digitgrade is onyld igts o the ground - in running/sprinting
57
what are the thee steps of neural control of gate?
1) heel contact 2) toe off and swing intiation 3) swing
58
what happens tot hemuscle during heel ocntact of walking?
dorsiflexion eccentric Eccentic quadsr (knee extensors)
59
what happens to muscles during the toe-off and swing initiation phase
concentric of plantar felcors Concentric quads (esp rectus femoris)
60
what happens to the muscle during swing phase of walking?
concentric of dorsiflexors eccentric of hamstrings (knee flexors)
61
Neural control of gait: Does the cortex control alternating pattern of muscle activity for locomotion? What proves this?
decerebrate cats are still able tog cenerate gait cyle if posture is supported means alternating activity must result from spinal cord mechanisms
62
what controls altenrating pattern of muscle activity for locomtion ?
Central pattern generator - a group of neurons in the spinal cord organized to alternate the rhythmic control of location specialized for each rhytmic acivity - walking, swimming, breathing, swallowing...
63
what is the target therapy for spinal chord injury?
gait recvoery
64
what evidence is there of spinal walking in humans
children below one have no corticospinal input onto alpha MN that controls lower limb muscles
65
name 4 things taht sesnory modulation is important for in locomotio?
initiating walking controlling phase transitions (stance to swing) regulating muscle activity correcting for unexpected disturbances
66
explain how sensory modulation is involved in the controlling phase and timing of transitions in walking
making the transition from stance tos wing during walking muscle spindle --> stimulated withs tretch of hip flexor
67
in walkign muscle spondles are stimulated with stretch of ___ and this signal___
hip flexors - signals swing phase to be initiated
68
what 2 things happen in controlling phase and timing of transitions ocne the muscle spindles are stimualted
once the is msucle spindthe le stimulated from stretch of hip flexor 1) signla swing phase 2) inhibit knee extensor and aid in knee flexor activity
69
what is the stumbling corrective response?
encounter an obstacle during the swing or stnace phase - stimulate muscle and cutaneous receptors leading to automatic flexion to step over the tehobstavle (swing) or extension (stance)
70
the stumbling corrective reponse stimulates ____ receptors
cutaneous and muscle
71
True or false. The stumbling corrective response stimulates joint receptors
false - muscle and cutaneous
72
in the stumbling corrective response, what happens if we are in the swing vs stance phase of working
swing - automatic flexion to clear obstalnsce stance - automatic extension to push up over substance, shortening/accelerating stance phase
73
Nigel is tired from staying up all night prepping for the Cat Trivia Olympics. He is quite tired and wants to have a sip of his coffee. From a neurophysiological perspective, how is he able to pick up his coffee and take a drink?
Visual info entera te eye retina --?> optic nerve __> lateral geniculate nucle us (in thalamus) -> V1 --> occipital lobe - relays info to secondary somatosensory projects to: a) the secondary SS cortex( located in aprital lobeparie) - where it is b) inferotemporal lobe - venral path - object recognition (what pathway)t to rpefrontal coretex (decision) to premotor - submit to motor

Human Motor behaviour (21 decks)

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