3

Question 1

Spinal card organization

Answer 1

Spinal cord has the white matter on the outside while the gray matter is located inside.
The cell body of the sensory/afferent neuron is on the dorsal root ganglion which is located outside of the CNS.
Sensory information comes to the spinal cord from the dorsal root (posterior root) and it leaves from the ventral root (anterior root).
There is a posterior horn (towards the back and narrow) and an anterior horn (towards the front)
What connects the left and right side of the spinal cord is gray commissure.

Question 2

Three major sensory tracks

Answer 2

• Posterior column tract (dorsal column medial lemniscus DCML)
• Spinothalamic tract
• Spinocerebellar tract

Question 3

Chains of neurons

Answer 3

• First order neuron: Delivers sensation to CNS, their cell body is in the dorsal or cranial root ganglion
• Second order neuron: An interneuron with the cell body in the spinal cord or brain
• Third order neuron: Transmits information from the thalamus to the cerebral cortex

Question 4

Sensory tract organization

Answer 4

• Sensory modality: Fine touch sensations are carried in one sensory tract
• Somatotopic: Ascending tracts are arranged according to the site of origin
• Medial lateral rule: Sensory neurons that enter a lower level of the spinal cord are more medial within the spinal cord. Sensory neurons that enter at a higher level of the spinal cord are more lateral within the spinal cord.

Question 5

Brain mapping-homunculus

Answer 5

A cortical homunculus is a distorted representation of the human body, based on a neurological map of the areas and proportions of the human brain dedicated to processing motor functions, or sensory functions for different parts of the body.
The biggest areas of the brain dedicated to somatosensory and motor learning are in the hands and face.

Question 6

Gray commissure

Answer 6

It is what connects the left and right side of the spinal cord

Question 7

SAME DAVE

Answer 7

sensory afferent
motor efferent
dorsal afferent
ventral efferent

Question 8

Posterior column tract (dorsal column medial lemniscus DCML)

Answer 8

Transmits proprioception, fine touch, pressure, vibration to primary sensory cortex on opposite side of stimulus.

Question 9

Spinothalamic tract

Answer 9

Transmits pain and temperature sensations to the thalamus and then to the sensory cortex on opposite side of the stimulus

Question 10

Spinocerebellar tract

Answer 10

Transmits proprioception sensations to the cerebellum on same side of the stimulus.

Question 11

Brodmann areas

Answer 11

Primary motor cortex (4)

Primary somatosensory cortex (1,2 & 3)

Visual information- Posterior parietal cortex (7 & 5) Once the visual information is sent to the occipital lobe, it then splits into dorsal and ventral stream. The posterior parental lobe (Dorsal stream) is used as a secondary processing area of visual information.

Question 12

Signal detection theory

Answer 12

Is the ability to differentiate between a signal/stimulus and a random pattern that distracts us from the information.
concerned with the accuracy of responses
not under time pressure but less than 100% accuracy
un paced task

Question 13

Perceptual sensitivity D

Answer 13

Is the distance between the two means.
The larger the Perceptual sensitivity, the easier it is to differentiate between the two. There is going to be more correct decisions (hit and correct negative) and less errors (false alarm and miss).
The smaller the Perceptual sensitivity, the harder it is to differentiate between the two. There is going to be more errors (miss and false alarm) and less correct decisions (hit and correct negative).
- important to note that errors and correct decisions are related to one another.
- In order to do a task better, the perceptual sensitivity needs to be larger (the difference between the means need to be large).

Changes in D are due to environmental factors or individual differences

Question 14

Observer criterion B

Answer 14

The cutoff criterion can move right or left on the sensation axis and reflects the position of the cutoff axis
The position of the cutoff is determined by the performer and depends on his expectancies and the rewards and penalties in the situation

Question 15

Perceptual performance depends on

Answer 15

1. Perceptual sensitivity of the performer

2. Expectancies about the performer and the rewards and penalties inherent in the situation

Question 16

Novice vs expert drives

Answer 16

• Novice drivers require a higher level of danger to be present before they are willing to respond to a hazardous situation
• No differences were shown in the sensitivity perception of hazardous situations
• For experts, this leads to the adoption of lax criterion, even though this means an increase in false alarms

Novices
hits: 50%
false alarms: 16%

Experts
hits: 84%
false alrams: 50%

Question 17

Discriminatory reaction time

Answer 17

concerned with time to respond with accuracy constant
100% accuracy if given sufficient time to response
forced paced task
It is the time it takes for a person to discriminate between two things.
The more alike the stimuli, the longer the DRT.
The easier the stimuli, the faster the DRT.

Question 18

Crossman’s confusion function

Answer 18

The law relating DRT (Discriminatory reaction time) to the degrees of discriminately of two stimuli.
It is basically a law that predicts the reaction time which is based on the similarity of two stimuli.
1. They need to be presented simultaneously
2. Can be measured along a physical dimension in terms of discriminability differences

Question 19

Pattern recognition

Answer 19

• Recognition of complex patterns relevant to a sport, differentiates skilled and unskilled athletes
• Fundamental perceptual abilities cannot explain skill differences
• Pattern recognition is critical for the success of skilled performers

Pattern recognition can be improved through perceptual learning

Question 20

Static and dynamic visual acuity

Answer 20

Static visual acuity is not related to performance is at least normal, but below average it may be a limiting factor
Dynamic visual acuity: There is a 0.3-0.4 correlation between dynamic visual acuity and performance but this is a very moderate relationship. However, dynamic visual acuity is still more important compared to static visual acuity in relation to performance.
SVA and DVA relate to innate abilities.

Question 21

Optical flow field

Answer 21

It is the expansion, contraction or regular movement of all the stimuli in the field of view.

Question 22

Time to contact (tau)

Answer 22

Cues associated with timing information about moving objects are crucial to a variety of activities
Timing information is needed to know when contact will occur
- Subjects could discriminate a time to contact difference of 150 ms with 90% accuracy

Question 23

Tau

Answer 23

Tau is the time to contact or time to collision between object and the observer and it is specified by the
size of image (on retina)/velocity of expansion of image (on retina)
Tau y (time until ball hits the ground)/Tau x (time until ball hits eyeballs)
- If the ratio is 1, then the ball intersects the eye
- if the ratio is more than 1, then the ball will land behind the fielder
- If the ratio is less than 1, then the ball will land in front of the fielder

Question 24

Decision making

Answer 24

This is a stage in the information processing model in which a response has to be selected.
It is between perception and the effector mechanism.
The decision making stage is still dealing with reaction time and not movement time.

Question 25

Brain regions involved in decision making

Answer 25

• prefrontal cortex
• Striatum (Basal ganglion)
• pre motor cortex

Question 26

Prefrontal cortex

Answer 26

The prefrontal cortex not only shows increased activity during decisions requiring self control, but during all decision making processes.
It is split between behavioural control and decision making

the neural interactions bw the dorsolateral and ventromedial prefrontal cortex not only play a central role when a person needs to decide between options during goal directed behaviour but also active during flexible decision making

Question 27

Striatum (basal ganglion)

Answer 27

• It is part of the basal ganglia (which makes up the inner core of the brain) and processes both decision making and subsequent actions.
• There are two parts to it: putamen and caudate nucleus (head, body and tail) So putamen and caudate with its three parts make up the striatum
• Involved in reward based decision making, like eating food, drugs and etc

Question 28

Premotor cortex

Answer 28

• it is part of the brodmann area 6
• It is an area of motor cortex lying in the frontal lobe, just anterior to the primary motor cortex. it is involved in planning of movements but also has other unknown functions.
• The premotor cortex decides what actions are desired, while the motor cortex decides how the actions are supposed to be carried
• Receives multiple sensory inputs, particularly visual, used to guide movements
• Influenced by cerebellum via thalamus
  selecting movements based upon sensory cues, from a repertoire of possible movements.

damage impairs ability to plan strategies
input from posterior parietal cortex
not well understood

Question 29

Supplementary motor area

Answer 29

• It is internally movements (self motivated)
• They are learned sequences like typing
• Associated with bimanual control
• Influences by basal ganglia via thalamus

planing of complex and 2 handed moves
coordinates posture

Question 30

Summary

Answer 30

• prefrontal cortex plans
• premotor cortex sequences
• motor cortex executes

Question 31

Choice reaction time

Answer 31

Is based on the idea that the number of stimuli and the responses that are based on the stimuli will affect your reaction time.
The more choices you are presented with, the slower your choice reaction time.
For an unskilled player, RT will be about 150 msec greater than simple reaction time. Now this is reduced or disappears for a skilled player.

Question 32

Hick Hyman law

Answer 32

x: log 2 n
where n is the number of stimulus-response
The trained person will have a smaller slope and that is due to their training. A smaller slope indicates that they have a faster choice reaction time.
In this case, we are manipulating the choices we have.

The reason our slope decreases is because of practice, and so we bypass that limited information processing capacity that we have and instead we use the long term memory which is way faster.

Question 33

Stimulus response compatibility

Answer 33

is though of as indicating degrees of practice on a particular configuration compared to another.
The higher the compatibility, the more the configuration has been practiced in our daily lives
- Stroop test is an example of S-R compatibility

Question 34

psychological refractory period

Answer 34

psychological refractory period is the reason why faking works and why distraction is not good.

• Stimulus onset asynchrony (SOA) is the delay between stimulus 1 and stimulus 2.
• Slack is the delay of information processing when stimulus 2 is presented.
• If an action begins in response to a stimulus, then there is a delay of at least 100 msec in addition to the normal reaction time to respond to a second stimulus and this is only true if the second stimulus is presented within 50-200 msec after the first stimulus.

Question 35

anticipation

Answer 35

Is using learned cues to predict future events.

It is critical for success in open skills

Question 36

Effector mechanism

Answer 36

This is the third stage of the information processing model.
The task of the effector mechanism is to organize motor system for the desired movements.

Question 37

Control of voluntary movement

Answer 37

• Cerebral cortex
• Basal ganglia: controls position and the initiation of voluntary movement
• Cerebellum: Monitors muscles during movement

Question 38

Three stages of movement

Answer 38

Stage 1: Prefrontal cortex plans the movement based upon information from the post parietal cortex about spatial perception (dorsal stream). Basal ganglion is also involved
stage 2: Secondary motor areas including premotor area and supplementary motor area work with the cerebellum to specify the precise sequence of contractions of the various muscles required.
stage 3: primary motor cortex, the brainstem and the spinal cord are all involved to produce the contractions of all the muscles needed.

Question 39

Primary Motor cortex

Answer 39

Inputs: supplementary motor area, post parietal cortex, primary sensory area and premotor area
Outputs: Thalamus, cerebellum and basal ganglion

main area for executing voluntary movement
electrical stimulation produces movement
involved in the initiation and execution of movement
specify how actions are carried out
neurons in M1 fire immediately before and during voluntary movement
this neural activity encodes two aspects of the movement: direction and force

Question 40

Levels of organization for movement

Answer 40

• Pre command: cerebellum and basal ganglia
• Projection: primary motor cortex and brain stem nuclei
• Segmental: Spinal cord and central pattern generator

Question 41

Pre-command level

Answer 41

• cerebellum and basal ganglion
• regulate motor activity
• precise stop and start of actions
• block unwanted movements
• coordinate movements based on posture
• monitor muscle tone

Question 42

Projection level

Answer 42

• Consists of upper motor neurons from motor cortex that initiate the direct pathway to produce voluntary skeletal muscle movements (also called the pyramidal tract or direct pathway)
• Brain stem motor areas- oversees the indirect pathway to modify commands of the direct pathway (also called extrapyramidal tract indirect pathway) modify ongoing actions
• Projection motor pathways send information to lower motor neurons and keep higher command levels informed of what is happening.
• brainstem areas oversee movements
• integrate visual and vestibular information
• helps control reflex and fixed pattern activities

Question 43

Segmental level

Answer 43

• spinal cord
• lowest level of the hierarchy
• controls locomotion and repetitious moves

Question 44

Motor cortex disfunction (lesions)

Answer 44

• paralysis
• hemiparesis
• monoparesis

Question 45

Motor plan

Answer 45

An abstract representation of an intended movement

Question 46

Supplementary motor cortex disfunction

Premotor cortex disfunction

Answer 46

SMA: disrupt self initiated movements, impaired bimanual coordination, and alien hand syndrome

PMA: weakness of movements, and impair the movements elicited by sensory cues

Question 47

Components of the basal ganglia

Answer 47

• Input: striatum (putamen and caudate nucleus)
• Output: globus pallidus (indirectly substantia nigra)
• At rest: subthalamic nucleus and substantia nigra

Question 48

Functions of the basal ganglia

Answer 48

Voluntary control of movement: Initiation of voluntary movement, inhibits other movements, changes between movements, and adjusts movements while in motion.

Postural control: righting reflex and automated movements

Muscle tone control: Vestibulospinal

Chooses a particular movement or a sequence of movements out of many possible responses.
Controlled action requires both go and stop

Programs self initiated movements
Movement initiation: Processes internal triggers from memory to combine motor actions into routine.
Self initiated movement rather than stimulus triggered movement
Control of habitual, skill based behaviours

Planning and control of complex movements
Organize sequences of movements into smooth, automatic whole

Question 49

Disorders fo the basal ganglia

Answer 49

Parkinson’s disease (hypokinetic): Caused by neuron death in substantia nigra. loss of dopamine disrupts normal modulations of basal ganglion output.
Akinesia – difficulty initiating movement
Bradykinesia – slowness of movement
Rigidity – stiff inflexible limbs

Huntington’s disease (hyperkinetic)
Chorea – unpredictable, involuntary movement
Ballism – flailing limbs, undesired motion
Athetosis – hand wringing

Tourte syndrome
Tics/tremors – Tourette Syndrome

Obsessive compulsive disorder

Question 50

Cerebellum structure

Answer 50

• It contains more neurons than the total from the rest of the brain but it only takes up 10% of the total brain volume.
• The number of neurons in the cerebellum is related to the number of neurons in the cortex. There are about 3.6 times as many neurons in the cerebellum as in the cortex, a ratio that is true across many different mammalian species.

Question 51

Function of the cerebellum

Answer 51

Responsible for fine motor movement, balance, Fine tuning movements and the brain’s ability to determine limb position.
The cerebellum does not initiate movement, because it has no direct connection to motor neurons.
The cerebellum rather than the cortex plays an important role in learning and remembering of movements, also known as non-declarative/ procedural memory.

Contributes to coordination (assemble components of complex multi-joint or multi- limb movements.), accuracy of actions (uses sensory feedback to correct for errors in movement by comparing feedback to the intent of a “motor plan”), timing of actions (correct order and timing of individual muscle activation; timing of movements) and skill learning (acquire new motor skills).

receives input from sensory systems of the spinal and other parts of the brain and integrates these inputs to fine tune motor activity.
regulates movement and posture

Question 52

Neuroanatomy of the cerebellum

Answer 52

• Cerebrocerebellum – input from cortex. Involved in planning and initiating movement.
• Spinocerebellum – input from spinal cord. Information about limb position and touch and pressure feedback. Useful for correcting or modifying movement.
• Vestibulocerebellum (Floculonodular lobe) – equilibrium, balance for posture
• Vermis – connects left and right hemispheres. posture, limb movements, eye movements.

Question 53

Communication with the nervous system

Answer 53

Communicates with the rest of the nervous system via peduncles.
Peduncles connect cerebellum to brain stem at the level of the pons.

• Superior peduncle – primarily output. Connect to midbrain.
• Middle peduncle – primarily input from rest of brain. Connect to pons.
• Inferior peduncle – primarily input from spine. Connect to medulla oblongata

Question 54

Cerebellar inputs and outputs

Answer 54

Inputs: motor cortex, inner ear, spinocerebellar tracts, muscle and joint proprioceptors

Outputs: Motor cortex, reticulospinal and vestibulospinal tracts, limb and postural muscles

Question 55

Damage to cerebellum

Answer 55

Vestibulocerebellum –

• Loss of balance
• altered walking gait
• wide stance

Cerebrocerebellum –
- Problems with skilled movements: errors in
speed, force, direction, amplitude of moves
- Hypotonia, intention tremor, dysmetria,
ataxia

Spinocerebellum –
- Uncoordinated, poorly aimed movements

Question 56

Disorders of the cerebellum

Answer 56

Ataxia: a lack of muscle coordination in voluntary movements. Can cause:
• Poor coordination
• Unsteady walk and a tendency to stumble
• Difficulty with fine motor tasks, such as eating, writing or buttoning a shirt
• Change in speech
• Involuntary back-and-forth eye movements (nystagmus)
• Difficulty swallowing

Dysmetria = Patients will “past-point” (i.e., reach past a target, or fall short of the target)

Intention tremor = (brought out by voluntary movement). Characteristically, the tremor is 1) more pronounced as the patient approaches the endpoint; 2) affects the shoulder and hip girdle muscles predominantly); and 3) the direction of the tremor is perpendicular to the movement of the limb.
• at rest there will be little or no tremor.

Hypotonia = very low muscle tone

Question 57

Cerebral cortex

Answer 57

control of voluntary movements
language
personality
complex process- thinking, planning, decision making and creativity

Question 58

Basal ganglion

Answer 58

Inhibition of useless movement
coordination of slow, sustained movements
inhibition of muscle tone

Question 59

Thalamus

Answer 59

relay station for all sensory input
some awareness of sensation
role in motor control

Question 60

cerebellum

Answer 60

maintenance of balance
coordination and planning of skilled movements
enhance muscle tone

Question 61

Brain stem

Answer 61

cardiovascular, respiratory, and digestive control centres
regulate reflexes for equilibrium and posture
synaptic reception and integration from spinal cord
activation of cerebral cortex
role in sleep wake cycle

Question 62

Information transmission to muscles

Answer 62

• Axons travel through Descending Tracts (Pathways)
• Some originate in cerebral cortex, others in spinal cord
• No synapses in the descending pathways.
• At destination the neurons synapse with a lower motor neuron.

Motor pathways usually contain two neurons
• Upper motor neuron - within CNS
• Lower motor neuron - from CNS to muscle

Question 63

Descending tracts

Answer 63

All the neurons within the descending motor pathways are classed as upper motor neurons. Their cell bodies are found in the cerebral cortex or the brain stem, with their axons remaining within the CNS.

The motor tracts can be functionally divided into two major groups:
• Pyramidal tracts (Voluntary Movements)
• Extrapyramidal tracts (Involuntary Movements)

Question 64

Pyramidal tracts

Answer 64

The name comes from the medullary pyramids of the medulla oblongata, which the axons pass through.
Origin: Cerebral cortex
Descend: they carry motor fibres to the brain stem and spinal cord
responsible for voluntary control of musculature of the body and face

Functionally, the pyramidal tract can be subdivided into two tracts:
Corticospinal tract: conscious control of skeletal muscle of the body
Corticobulbar tract: conscious control of skeletal muscle of the head and neck

Question 65

Extrapyramidal tracts

Answer 65

They originate from the brainstem
They carry motor fibres to the spinal cord
responsible for the involuntary and subconscious control of all musculature, such as muscle tone, balance, posture and locomotion.
Vestibulospinal and Reticulospinal do not decussate, providing ipsilateral innervation.
Rubrospinal and Tectospinal do decussate, and provide contralateral innervation.

Question 66

Summary of the role of descending tracts

Answer 66

The cerebellum is important in contributing to the motor system because it compares cerebral motor commands with proprioceptive feedback.

The corticospinal fibres that project to the ventral horn of the spinal cord have branches that also synapse in the pons, which project to the cerebellum.

The proprioceptive sensations of the dorsal column system have a collateral projection to the medulla that projects to the cerebellum.
these two streams of information is compared in the cerebral cortex

Question 67

Red nucleus

Answer 67

Conflicts bw the motor commands sent by the cerebrum and body position information provided by the proprioceptors cause the cerebellum to stimulate the red nucleus.
The red nucleus then sent corrective commands to the spinal cord along the rubrospinal tract.
The red nucleus is a structure in the rostral midbrain
it is involved in motor coordination
the red nucleus is less important in primates than it is in other mammals
the crawling baby and the arm swinging during walking is controlled by the red nucleus.
the red nucleus plays a role in controlling muscles of the shoulder an upper arm. it has limited control over hands

the majority of the red nucleus axons relay information from the motor cortex to the cerebellum through the inferior olivary complex an important relay station in the medulla.

Question 68

Lower motor neurons

Answer 68

They are located in the ventral horn of the spinal cord
they innervate the muscle and are organized functionally

axial motor neuron and muscles: move the trunk, important for maintaining posture
proximal motor neuron and muscles: move the shoulder, elbow, pelvis and knees. critical for locomotion
distal motor neuron and muscles: move the hands, feed and digits; specialized for the manipulation of objects

Question 69

Motor units

Answer 69

motor neuron, motor axon and all the muscle fibres innervated by the motor axon.
the number of muscle fibres innervated will vary depending upon the muscle.
- gastrocnemius up to 2000 fibres
- eye muscles as few as 3 fibres

Question 70

Motor neuron pool

Answer 70

all the individual motor neurons that innervate a signal muscle.

• each individual muscle fibre is innervated by only one motor neuron, but one motor neuron can innervate several muscle fibres.
• ratio of motor neurons to muscle fibres affects the precision of movement.

Question 71

Corticobulbar tract

Answer 71

Corticobulbar tract: conscious control of skeletal muscle of the head and neck

• it receives the same inputs as corticospinal tract
• it descends to the brainstem
• Terminates on the motor neurons of cranial nerves. Synapses with lower motor neurons, which carry the motor signal to the muscles of face and neck.
• many of these fibres innervate motor neurons bilaterally
• eyes, chewing, tongue, expressions and speech

Question 72

Vestibulospinal
Reticulospinal
Rubrospinal
Tectospinal

Answer 72

Vestibulospinal: receives input from vestibular system to control balance and posture by innervating anti gravity muscles (flexors of the arm and extensors of the leg)

Reticulospinal: Controls automatic locomotion and posture movements, automatic functions and muscle tone.

Rubrospinal: Originates from the red nucleus. primarily upper body. thought to play a role in the fine control of hand movements
Tectospinal: Originates in the superior/inferior colliculus
Coordinates movements of the head in response to bright light and sudden moves or loud noises.

Question 73

Lateral tracts

Medical tracts

Answer 73

Lateral tracts- control distal/ extremities (allow for fine motor control)

• corticospinal tract
• rubrospinal tract

Medical tracts-control axial muscles (posture, rhythmic movements)

• vestibulospinal tract
• tectospinal tract
• reticulospinal tract

Question 74

Inputs to motor neurons

Answer 74

motor neurons can receive input from
upper motor neurons in the brain
sensory input from muscle spindles
input from spinal interneurons

Question 75

Inputs to motor neurons

Answer 75

motor neurons can receive input from
upper motor neurons in the brain
sensory input from muscle spindles
input from spinal interneurons

Question 76

Two effector control system

Answer 76

Predictability needs to be measured in relation to the skill level of the performer.

• Open loop system: it purely uses ballistic (unguided) movements. it is fast but cannot cope with a changing environment and depends on motor memories stored in LTM.
• closed skill
• skilled performance
• Closed loop system: it uses feedback to modify ballistic movements. it is therefore slower but it can cope with a changing environment.
• open skill
• unskilled performance

Question 77

Feedback system (1 and 2)

Answer 77

Loop 1: is when the feedback comes from effector stage and goes back to the effector stage again.
- Alpha gamma co-activation system

Loop 2: is when the feedback comes from the effector stage and goes back to perception stage.
- delayed feedback
delayed auditory feedback- there is a reflexive but relatively slow (200 msec) auditory feedback system for controlling the muscles used for speech production.
this system is revealed by delaying feedback, this causes speech disruption.

• aimed movements
  Fitts law relates movement time to the amplitude of the movement and the required accuracy.
  this holds true for aimed movements that are made as quickly as possible.

Question 78

Alpha gamma co-activation system

Answer 78

• functions to maintain smooth ballistic movements, stabilizing system for walking, picking up objects
• very fast (50 msec), reflex, therefore processes information without requiring conscious processing capacity
• this system is demonstrated by patellar tendon reflex. tendons are stretched in quadriceps muscle.

Question 79

Fitts law

Answer 79

Fitts law relates movement time to the amplitude of the movement and the required accuracy.
this holds true for aimed movements that are made as quickly as possible.
the x is the index of difficulty

how can practice decrease the movement time to a target? make the movement time faster?

• More accurate muscle impulses would mean fewer corrections which take time-effector processing
• the visual feedback could be processed more efficiently- perceptual processing

Question 80

Open loop systems

Answer 80

catching a ball or golf are examples of open loop.

open loop uses parallel processing

Question 81

Types of long term memory

Answer 81

• Declarative memory (experience and facts)
  medial temporal lobe
  sensory association cortex
  hippocampus
• Non declarative memory
  non associative: habitual, sensitization, reflex pathway
  assosiative: amygdala, cerebellum and motor cortex
  procedural memory: sensory and motor cortex, cerebellum and basal ganglia

Question 82

Motor learning

Answer 82

Motor learning is an improvement of motor skills through practice, which produces long lasting neural changes

a more descriptive term is sensorimotor skills. Learning requires multiple receptions of a movement, usually under a variety of conditions.

Question 83

Motor programs

Answer 83

• a representation in long term memory of a movement sequence that has been acquired through learning.
• it is the equivalent of chunking in perception
• can be run off without the need for feedback. so open loop control can be explained by the motor program.
• also, it can be one way to manage the degrees of freedom problem.

Question 84

Measuring learning

Answer 84

• performance curve
• retention test
• transfer test

Question 85

power law of practice

Answer 85

• individual curves are highly variable but are smoothed by averaging and can then be described by the power law of practice (learning)
• learning curves for a variety of perceptual motor tasks can be described by the power law of practice.

Question 86

Motor learning problems

Answer 86

Performance plateau: no apparent improvement occurs in performance despite continued practice

degrees of freedom
- when teaching a skill, try to decrease the degrees of freedom in a situation.
there are three solutions to the degrees of freedom:
- movement efficiency- use mid range of joint angles
- smooth movements- minimize jerk (rate of change of acceleration)
- dependencies bw components of the motor system will reduce the degrees of freedom (synergy)

Question 87

An aimed movement has two parts:

Answer 87

• an initial muscular impulse which leads to a ballistic movement toward the target. the ballistic movement is controlled by the muscle spindle system
• one or more visually guided corrections. this visually guided feedback is much slower and is an example of feedback loop 2.

Question 88

Evidence for motor programs

Answer 88

• the effects of movement complexity on RT (more complex: slower RT)
• deafferentation experiments (block sensory information)
• blocking a limb during motion (EMG recordings similar)

Question 89

How do we represent motor programs in our LTM?

Answer 89

• Invariant characteristics
  relative force, relative timing, and order of movement components
• changeable parameters
  absolute (overall) force, timing and spatial position

Question 90

Lateral corticospinal tract

Answer 90

Decussates
descend into the spinal cord, terminating in the dorsal horn. then to the muscle of the body.
75-90% of voluntary movement.

Question 91

anterior corticospinal tract

Answer 91

it remains ipsilateral
descending into the spinal cord
decussates and terminate in the ventral horn of the cervical and upper thoracic levels
10-25%

Question 92

Researcher have observed

Answer 92

When the primary motor cortex activity is disrupted, errors in movement production occurs
when supplementary Motor area activity is disrupted, there are errors in sequencing movements