MOTOR CONTROL Flashcards
(135 cards)
1
Q
What are the main 6 things that belong in the CNS
A
- brain
- cerebral cortex
- basal ganglia
- cerebellum
- brain stem
- spinal cord with central nerves
2
Q
What is a voluntary movement
A
a movement we do consciously
3
Q
6 Steps of motor planning and execution
A
- input
- deciding what to do
- pre planning
- scaling and fine tuning
- execution
- sensation and feedback
4
Q
what is the hierarchy in the motor control process
A
at the top
- cognition/decision making
- motor planning
- translate into motor commands
- carry motor command
- execute motor command
as you go down they get more specific
top 3 are in the cortex, then fourth in in the brain stem and the fifth is in the spinal cord
5
Q
Cerebral Cortex: grey vs white matter
A
Grey matter is neuron bodies which are processing
white matter is where the axons are, which is where they transporting of signals happens
6
Q
Cerebral Cortex: folded surface
A
the cerebral cortex has a folded surface so that is can maximise its SA to accommodate a large number of neurons
7
Q
Cerebral Cortex: What are the 3 main cortical regions for movement and their main role
A
Pre frontal cortex = general outline of behaviour
pre motor cortex = specific motor planning
Primary motor cortex = executes motor programe
8
Q
Pre frontal Cortex
A
this is where we decide what to do, this is where all the information, from the world and the body comes to and it selects what needs to be processed, and weighs all the consequences of activities.
9
Q
Pre Motor Cortex
A
this is where the pre planning and preparation of a movement occurs. it retrieves long term memory to adapt a plan whilst also using sensory information, and postural plans
10
Q
Primary Motor Cortex
A
this is where the motor programme is executed. this controls the muscle activity , and this is where those commands are launched from
11
Q
Motor Cortex - Launch Pad
A
this is where the final details are determined, it receives feed back form the movements, which is can make adjustments too
12
Q
Motor Cortex - representation of body areas
A
- body areas are represented geographically = motor homunculus
blown up parts in the brain have more neurons which allows them to have better fine tuning movements
13
Q
EEG measures …
A
the activity of regions in the cortex
14
Q
Brain Stem: Executing and modifying
A
the command travels via the brain steam, spinal cord to the nerves in the musculoskeletal system. the information is able to travel book ways so we can receive and evaluate information.
15
Q
BrainStem
A
is a descending pathway between the cortex and spine. it works in two directions,
- it transports signals from the spinal cord to the rest of the brain
- transports motor commands from the brain to the motor neurons in the spinal cord
16
Q
Pathways in the Brain stem
A
75% of the motor neurons cross the midline, to control the distal muscles on the opposite side
25% of the motor neurons stay on the same side of the body to control the axial muscles
17
Q
Spinal Cord vs the Spinal Column
A
the spinal cord in found in the spinal column as it protects it
18
Q
Spinal Cord
A
is a bundle of nerves running from the brain to the muscles and sensors
19
Q
Cerebellum
A
is where more than half the brains neurons are found. it has a significant role in timing and motor learning
20
Q
Basal Ganglia
A
is important for preparation and scaling
- it retrieves the movement plans
- is sales the movement of the paramenters
- movement preparation.
21
Q
Synapses
A
are neuron to neuron. electrical - chemical - electrical
neuron - muscle fibre. electrical to chemical
22
Q
Muscle Innervation
A
when an action potential arrives at the end of a neurons axon it triggers a response in the muscle fibre. a neurotransmitter is released and the muscle dibre them contracts
23
Q
Motor Neurons
A
1 muscle fibre is only activated by 1 motor neuron by a motor neuron can activate many muscle fibres
24
Q
Alpha Motor Neurons
A
these are the biggest neurons and that innervate the skeletal muscles
25
Afferent vs Efferent
afferent is towards the brain whereas efferent is away from the brain
26
Motor Unit
is one motor neuron and then many muscle fibres. could be 1 muscle fibre or could be 1000+
27
What are the 3 types of motor units
Fast Twitch - Fatigue (lots of force fast, but lose it fat)
Fast Twitch - Fatigue Resistant
Slow Twitch - Fatigue Resistant (less for but last for so long)
28
What are the two method for controlling force (increase the muscle force)
1. recruit new motor units
2. increase the frequency of firing of already recruited motor units
29
Electromyography (EMG)
electro - electrical activity
myo - muscle
graphy - record
recorded in volts
two methods
surface EMG = less precise
intramuscular EMG = can measure motor unit action potential
30
Muscle Spindles give feedback of
the length of muscle
31
Spinal Reflexes
afferent neurons from sensory organs project to the spinal cords, where some processing can occur without the brain
32
Example of a short look reflex loop
1. muscle is stretched, muscle spindle fires
2.afferent neuron to spinal column
3. synapses directly onto the agonist and to the inhibitory interneuron to the antagonist muscle
5. causing the muscles to contract which relieves the stretch of the muscles, then the spindle stops firing
6. the sign subsides then the muscle stops contracting
33
Recurrent inhibition
motor neurons inhibit themselves. motor units activates inhibitory, that inhibits the same MN
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Reciprocal Inhibition
activation of on muscles inhibits the activity of the opposing muscle
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Co-Contraction
activation of the agonist causes activation of the antagonist
36
Tuning of the Spinal Control Loops
spinal cord works with the brain.
reflex thresholds can be lowered or increased.
37
Action Preperation
the activity that occurs between the intention to perform an action and the initiation of the action
38
What happens during action preparations
1. stimulus indentification
2. response selection (motor programme)
3. response programming - fine tuning
4. phirperal process - muscle activation
also
- postural preparation
- limb preparation
- sequence of limbs preparation
- ryhmitacy preperation
39
The motor programme
all are theories, we don't actually know, but our brain has a blueprint of a movement in our brain, which can be adapted
40
Postural Preparation
organising a synergy of postural muscles prior to performing an action
- APA's pre-movement: posture and tonus of muscle prepares system for movement
41
Preparation of Limb Movement Characteristics
this is the selection and organisation of specific limb movements which depend on
- movement direction, trajectory and spatial accuracy
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Preparation of Movement Characteristics
Setting the amount of force required, it is ones expectancies, about an upcoming performance, influence their performance
43
Preparation for Sequences of Movement
for skills that require sequences
- short sequences are prepared in advance of the initial movement
44
Rhythmicity Preperation
Pre-performed Rituals that can be used to stabilise the motor control system , have success on performance
45
What Happens During Action Preparation: Number or Response Choices
Simple RT: One stimulus and one response
Choice RT: Make a Decision
Discrimination RT: Tell the difference between the stimuli
Overall - the more decisions you have to make the longer the reaction time, and the longer for movement preparation
46
How to measure Action Preparation Time
Reaction Time is the time from stimuli to the movement initiation
Premotor Time: is the time from the stimuli to the electrical movement within the muscle
Motor Time: is the time from the electrical movement to the actual movement of the muscle
if the task involves more infomation processing the premotor and reaction time will get longer the motor time is always the same
47
Predictability of Correct Response
reaction time decreases as the predictability of one of the possible choices increases
PRIMING - is providing information on what may happen
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Stimulus Response Compatibility
RT will be faster when the relationship between the stimulus and the characteristics and their required response becomes more compatible
eg. stroop test
49
Foreperoid Predictability
is the time between the warning time and the go signal, always has to vary, so that it can be predicted
50
Reaction increase when the movement complexity ....
increases
51
Movement Complexity
the complexity of the action influences, the amount of time required to prepare for action. this suggests that central programming happens before the movement initation
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We rely on sensory information for
skilled behaviour
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Sensation vs Perception
sensory systems transform physical energy into neural signals
whereas perception is translating sensations into a meaning
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Process of Sensation
1. Reception - the ability of receptor to absorb energy of a stimuli
2. Transduction - conversion of the energy into membrane potential, a change in the permeability of the post synaptic membrane, which is often proportional to the strength of the stimuli.
3. Transmission - receptor potentials transmitted via ap's to the CNS
4. Integration - CNS processing of frequency of receptor potentials
55
What are the 3 main groups of receptors
interoceptors
proprioceptors
exteroceptors
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Interoceptors
states of internal organs
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Proprioceptors
information about our own movements
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Exteroceptors
information about the movement of objects in the environment
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Proprioception
sensation and perception of the position and movements of limbs, head trunk
60
Muscle Spindles
these give feedback of the length of our muscle, when it stretches.
1. spindles fire when the muscle is stretched
2. they send signals via neurons to the spine and up
3. they activate the muscle to contract to resist the stretch
4. the sensitivity of the spindles can be tuned.
61
Golgi Tendon Organs (GTO)
these give feedback of tendon stretch, which are very sensitive to muscle tension, and can help prevent injury
62
Joint Receptors
there are sensory endings in the joint, which help provide info about the joint angles
63
Cutaneous Receptors
these are in the skin, that measure the deformation of the skin
64
Sensory Adaption
Receptor responsiveness decreases with continual stimulation, as a ongoing stimuli is of constant intensity is it perceived as weaker overtime. but if a stimuli is of a variable intensity over a shorter period of time then is perceived as stronger over time
65
Why can't we tickle ourselves
as we know if coming, whereas when someone else does we don't perceive it
66
The Vestibular System
this provides information about the position and the movement of the head.
within the ear there are 3 semicircular canal which detect the hear acceleration and a utricle and sacculus which detect the acceleration and position of the head.
67
Movement Corrections
When the afferent pathways are surgically removed, the cat could still walk, but couldn't adjust his walking, due to the sensory information not going up to the brain to do so
68
What is the pathway of Sensory Information
Spinal nerves
spinal column
brain stem
thalamus
primary cortex
sensory association areas
69
Each modality has its own
primary cortical area
70
Pathway of Sensory Information - Association Areas
you recognise the relevant inputs, and the make sense of these inputs and then make a motor response out of it
if an area is damaged this is called Agnosia, where you may not be able to see them but can smell them etc.
71
What sensory system tends to dominate over others
Vision
72
Anatomical Structures Involved in Vision
Light from the object will enter the eye, and travel to the back to the retina, which are sensory cells, containing rods and cones, which turn the light into electrical impulses through transduction. These electrical impulses then travel up to the brain
73
Photoreceptors
Rods - peripheral retina, which are very sensitive to light and night vision
Cones - central retina, colour detection
74
Mono/Binocular Vision
one eye then two eyes, the motor control better when receiving information from both eyes.
half the information from each eye with cross to the other side of the brain and half will stay on the same side, so the brain can get information from both eyes giving overlapping vision and humans better depth
75
What are the 5 types of eye movements
- vestibular-ocular reflex
- optokinetic reflex
- smooth pursuit
- saccades
- vergence
76
What are the 5 types of eye movements: Vestibular-ocular reflex
stabilises the eye when the head moves
77
What are the 5 types of eye movements: Optokinetic reflex
maintains a stable image for the retina
78
What are the 5 types of eye movements: Smooth pursuit
track slow moving objects in space
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What are the 5 types of eye movements: Saccades
shift gaze between points if interest
80
What are the 5 types of eye movements: Vergence
brings objects at different depths into focus
81
Perception-Action Coupling Quote
"we must perceive in order to move, but we must also move in order to perceive"
82
Two Sensory Association Areas
1. Unimodal
2. Multimodal
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Two Sensory Association Areas: Unimodal
this is when it is specific to one mode that the information came from
84
Two Sensory Association Areas: Multimodal
this is when it integrates many sensory modalities. this receives more information
85
Two Visual 'Streams'
1. Perception pathway: which is the what are we seeing, as it connects the primary visual cortex with the temporal lobes = ventral stream
2. Action pathway: this is the how can we interact with the object. this connects the primary visual cortex with the posterior parietal lobes = dorsal stream
86
Perception pathway is ______ but vision for action is ____
impaired
fine
87
Vision becomes beneficial at movements lasting at least .....
250ms
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Fixations
this is when the gaze rests on a single object to process information
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Saccades
rapid movement of the eyes that change point of fixation abruptly
- this is the fastest type of eye movement
90
Measuring Eye Movement
1. light is directed to the eye
2. camera records the reflection of the light
3. from the reflection we can see the rotation of the eye
4. from the eye rotation we can deduce the direction of the gaze
91
Expert's gaze >>>>
- predict rather than react
- efficient visual search
- visual to relevant areas
- selective attention
92
Striking Sports
- you can't keep you eye on the ball the whole way through it's flight
experts - predict
minors - react
93
Visual Anticipantion
in time restricted tasks skilled athletes anticipate based on information from the enviroment
94
Skilled athletes possess a superior capacity to use their .....
central and peripheral vision
95
Experts fixated on more ____-_____ areas
task relevant
96
What is fatigue
it is the inability to maintain force during muscle contraction loss of ability to produce force, the deterioration in voluntary movement performance
97
Peripheral Mechanisms of Fatigue
this is fatigue produced by changes at or distal to the neuromuscular junction
98
Central Mechanism of Fatigue
fatigue is up stream to the neuromuscular junction
99
Peripheral - Muscular Mechanisms
within muscle -
1. a slowing of the nerve conduction velocity
2. altered excitation threshold of muscle fibres
3. longer relaxation phase of twitch contraction
4. post tetanic depression
restoration of a fatiguing muscle contraction can be mins to hours
100
Peripheral - Muscular Mechanisms: 1. a slowing of the nerve conduction velocity
- slowing means a delay of contraction, so the next contraction is even later
- slower rate of force development due to APs arriving at different times
- decrease in AP amplitude but increase in AP duration
101
Peripheral - Muscular Mechanisms: 2. altered excitation threshold of muscle fibres
cause the fibres are less likely to contract, so a stronger AP is required for the same force output
102
Peripheral - Muscular Mechanisms: 3. longer relaxation phase of twitch contraction
2/3 increase in time from the peak contraction to 50% of peak
- this reduces precision and timing of movements
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Peripheral - Muscular Mechanisms: 4. post tetanic depression
the force is smaller in a muscle after a fatiguing, tetanic stimulation
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Central Fatigue
failure of the nervous system to drive the muscle maximally
105
Spinal Mechanics of Fatigue
- decreased excitability of alpha motor neurons
- change in firing frequency on individuals motor neurons
- overall increase of firing rates of motor neurons
106
to increase muscle force the CNS can either
- recruit new motor units
- increase frequency of firing of already recruited units (rate coding)
107
Spinal Mechanics of Fatigue: Motor Neuron Rotation
to compensate for the drop in muscle force
- groups of motor units can be re/decruited
- larger motor units will decrease their firing rate/derecuit
- new motor units will be recruited
- the firing frequency will be increased for slow motor units
108
are smaller motor units or larger faster motor units more fatiguable
larger and faster
109
Spinal Mechanics of Fatigue: In Submaximal Tasks
while holding the force output constant the EMG activity increases to compensate for the fatigue, due to a loss of neural drive
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Other Effects of Fatigue
- impaired coordination
- increased variability of movement
- disrupts muscle spindles, increasing risk of injury.
- drowsiness
- attention
- motivation
- motor planning
due to depleted neurotransmitters
111
What is Cramp
painful involuntary contraction of a muscle or muscles, typically caused by fatigue or strain
112
Possible causes of Cramp
remains unclear, may be many possible causes, maybe -
- electrolyte imbalance
- neuromuscular control
113
Electrolyte theory
administration on a saline drink or salt tablets to miners would greatly reduce cramps, many other studies have shown no results
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Neuromuscular Theory
alpha motor neurons firing excessively, fatigue also leads to this golgi tendon firing
stretching helping cramps supports this theory
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Potential remedy for cramp
pickle juice
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What is attention
our limited capacity to engage with multiple cognitive and motor activities simultaneously
our need to selectively focus on specific environmental context features while performing a skill
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We have attention limits that limit our response to .....
environmental information
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Kahneman's Attention Theory
arousal influences how much of out maximal attention capacity is available
the less attention a task requires the more attentional resources are left over for other activities
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Automaticity
someone engages in a skill with a very limited demands on attention capacity, and is largely required through practice
120
How do we assess attention demands of a task
dual task procedures
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Dual Task Procedures
investigates the interference caused by the secondary task on the primary task
have a main task you want to see the impact an extra task has. eg a goal kick but have to remember the numbers behind the goal, and how does this impact you attention
122
Dual Task Procedures: Primary/Secondary Task
Primary = task of interest
Secondary = confounding tasks
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are attentional demands the same as attentional focus
no, attentional focus is the focus on specific characteristics in the environment
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Internal vs External Focus of Attention
internal = focusing on the internal body mechanisms eg. focus on your hip and knee
external = achieving something in the environment eg. push hard off the ground
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Internal vs External Focus of Attention: which is better
external focus
126
What is memory
is the capacity that permits organism to benefit from past experiences
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Memory Structure
sensory input - sensory memory - attention - short term memory - encoding to long term memory
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Working Memory
is the temporary use and storage of information
- the execution of memory and response production
- has a limited capacity
can last from 20-30 secs
can remember 7 ish items
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Can we improve our ability to retain info in the working memory?
we can't increase the capacity but we can change how the information is stored
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Long Term Memory
duration = relativity permanent
capacity = relatively unlimited - organisation is crucial
131
Procedural/Implicit Knowledge
this is subconscious, you learned, emotional response this is a motor skill you how to do
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Declarative vs Procedural Knowledge
knowing what to do vs doing it (hard to verbalise)
eg. ref does it but we know what to do
133
Why does simple RT take less time than choice RT
cause the central processing takes longer due to more choices, but the pheriperal process are the same lengths
134
Stretch Reflex Process Summary
Their is a patella tendon tap which causing a sensory stimulation, which causes the muscle spindles in the quads to get stretched which then are activated and fire a sensory afferent neuron, which carries to the spinal cord. In the grey matter of the spinal cord, 2 things happen
1. it directly synapses onto the agonist/motor neuron that it came from to contract it, so quads contract
2. a inhibitory neuron is sent to reduce the activation on the hammy, causing the hammy to relax
this contraction of the quad and relaxation of the hammy is what the little movement is caused by
135
Eye Open vs Closed during a faster movement
for some movements it doesn't matter as either way you will make a lot of mistakes
