251 Midterm 2

flexion-crossed extension reflex

flexion-crossed extension reflex

when you retract the injured leg, you press down harder with the other leg to not fall over

Plantar reflex

foot flexes inward

Plantar reflex (positive babinski's sign)

dorsiflexion of big toe

What does the GTO measure?

active force production

What does the GTO do?

shuts down the muscle to prevent ruptured tendons

autogenic inhibition

inhibition of the muscle when its force becomes dangerously high

Renshaw cell

inhibitory interneuron in the spinal cord. It is stimulated by a motor neuron (that would go to a muscle) and feeds back to inhibit that same motor neuron

Layer 5 neurons (betz cells)

send action potentials down descending spinal tracts

the motor homunculus

representation of the body parts and their correspondents along the precentral gyrus of the frontal lobe.

can the homunculus give an accurate indication

no

of the specific joints in which movement takes place

no because in most cases movement appears at more than one joint

stimulation of M1 (primary motor cortex)

the more you stimulate the more complex the movements

an M1 neuron tuning curve

Each neuron is TUNED to a particular direction of movement.

M1 population vector (red arrows)

show the overall POPULATION VECTOR for the various movement directions tested

M1 population vector (black lines)

represents a given M1 neuron, its orientation represents the neuron's preferred direction of movement, and the length of the line represents the firing rate.

VPLn def

relays somatosensory information from the body

VPMn def

relays somatosensory information from the face/oral cavity

Plastic def

subject to change depending on use

phantom limb sensation

the perception of sensations or pain in an amputated limb.

descending tracts

Brain down (motor commands). Includes LCT (lateral corticospinal tract) and VST (ventral corticospinal tract)

spinal neuroanatomy

just a diagram of spinal neuroanatomy

decussate

to cross over to the other side of the brain

Lateral corticospinal tract

a set of axons from the primary motor cortex, surrounding areas, and midbrain area that is primarily responsible for controlling the peripheral muscles

ventral corticospinal tract

Tract that carries uncrossed motor impulses to the spinal cord

The Dorsal Column Medial Lemniscus Tract

fine touch, proprioception, vibration

Ia axon

response to stretch

Ib axon

GTO

The Ventral Spinothalamic Tract

A pathway from the spinal cord to the thalamus that carries information about pain and temperature.

Aδ axon

myelinated usually information about pain and temperature

C axon

non-myelinated, usually information about just pain

do spinal tracts exists on both sides

yes they do

Where does decussation occur (Ventral Spinothalamic)

at the level it enters the spine

Where does decussation occur (Ventral Corticospinal)

N/A bilaterally innervates

Where does decussation occur (Lateral Corticospinal)

Brainstem (caudal medulla)

Where does decussation occur (Dorsal Column Medial Lemniscus)

Brainstem (Caudal Medulla)

What info does the VC tract carry and what direction

Motor - face and trunk and descending direction

What info does the LC tract carry and what direction

Motor - extremities and descending direction

What info does the DCML tract carry and what direction

Sensory - mechanosensory and ascending direction

What info does the VS tract carry and what direction

Sensory - Pain and temperature and ascending direction

Lesions meaning

damage

Paraplegia

Paralysis of lower body

Hemiplegia

paralysis of only one side of the body

Tetraplegia (Quadriplegia)

paralysis of all four limbs

Brown-Sequard Syndrome

causes paralysis and loss of touch/vibration/position sense on one side of the body, and loss of pain and temperature sensation on the opposite side

Febrile

having seizures due to high body temperature

What happens to anything if blood is cut off

it dies

Fine motor skills

The use of small muscles of the hands, finger, toes, wrists, lips and tongue to perform small, precise movements

Gross Motor skills

large movements that require large muscles in the arms, legs torso and feet

Examples of fine motor skills

threading a needle, picking up a coin

Gross motor skills examples

walking, standing up, reaching to open a door

open motor skill

require continuous evaluation of task and environmental demands

Examples of open motor skills

football, hockey, tennis, badminton

Closed motor skills

performer can evaluate environmental demands and prepare motor actions in advance (environment is stable and predictable)

Examples of closed motor skills

running a marathon, swimming

discrete motor skills

brief actions with a well-defined beginning and end and are important in sports and daily life

continuous motor skills

are repetitive and often cyclical with no clear beginning or end, performer can adjust the speed of movement

serial motor skills

composed of discrete skills strung together to make new more complicated skill

serial motor skills examples

many activities of daily life such as pouring a glass of milk, taking a sip of coffee

upper limb movements tend to be…

smooth, relatively straight and accurate with a “bell-shaped” velocity profiles

Invariant features of upper limb movements - behavioural task

Hand motion patterns remain relatively invariant despite markedly different joint motion patterns required to reach targets. The nervous system selects, plans and controls desired hand trajectories

Control of the movement trajectory

________ _______ considers movement planning and execution as two separate processes

What is slope and what is its variable

the rate of change in position (term a in equation), reveals differences in movement speed

What is intercept and what is its variable

it is the initial position (term b in equation), reveals differences in starting positions

Evidence that trajectory matters: experimental observations

Experimental observations

Hick’s law

A principle stating that the reaction time increases logarithmically with the number of choices.

Stimulus-Response Compatibility

The degree to which a stimulus and its required response are compatible with each other in terms of spatial or movement relationships.

Reaction Time (RT)

The time difference between stimulus presentation and the initiation of a motor response.

What are the stages of information processing in motor decisions?

Stimulus Identification (Perception), Response Selection (Decision), Response Programming (Action).

What is the difference between Simple and Choice Reaction Times?

Simple RT involves one stimulus and one response, whereas Choice RT involves multiple stimuli and possible responses, making it slower.

Give an example of spatial compatibility in S-R tasks.

Control dials aligned with their respective burners on a stove, allowing for faster, more intuitive responses.

What types of anticipation affect motor decision-making?

Temporal Anticipation, Spatial Anticipation, and Spatial-Temporal Anticipation.

What is Movement Time (MT)?

the time from the end of RT to the completion of the movement.

Which stage of processing determines what information from our surroundings is most relevant?

The first stage involves detecting and interpreting sensory inputs.

What happens in the stage of processing where we choose between possible actions?

This stage requires selecting an action based on task goals and environmental context.

Which step in processing involves preparing to perform the selected action?

This final step includes organizing the necessary movements to carry out the decision.

How do actions change when there’s an emphasis on moving faster over being precise?

As speed increases, the accuracy of the movement generally decreases.

When someone is aiming at a distant target quickly, what is likely to happen to the precision?

Precision tends to drop, especially as speed or distance increases.

What relationship exists between the consistency of movements and the level of force applied?

As force levels rise, maintaining a steady level becomes more challenging.

How does the complexity of a task impact the time taken to respond?

Higher complexity generally results in slower response times.

Which age group tends to make faster, smoother motions with fewer adjustments?

Younger adults typically show this pattern in their movements.

In a task involving rapid switches between two points, how do larger distances or smaller targets affect performance?

Greater distances or smaller targets require more time for each movement.

When a person applies maximum force, how does the steadiness of this force usually change?

The variability typically peaks near maximum effort and may slightly decrease as the limit is reached.

How does the range of motion affect the time it takes to reach a target?

Larger motions generally increase the time needed to reach a target, especially with accuracy requirements.

What happens to a person’s force consistency as they near their maximum force capacity?

Consistency in force decreases, showing greater variability near maximal effort.

How does the recruitment of different muscle fiber types affect movement control?

Larger fibers with higher force potentials contribute to greater variability in movements.

What difference is seen in the smoothness and speed of movements between young and older adults?

Younger adults generally produce faster, smoother movements with fewer corrections than older adults.

How is everyday design influenced by the need for accurate, quick responses?

Items frequently used, like large keyboard keys or important screen buttons, are designed to lower precision demands and speed up responses.

How does changing the ratio between motion distance and target size impact the difficulty of a task?

Increasing distance or decreasing target size raises difficulty, often resulting in slower movements.

In terms of accuracy, what is the effect of recruiting larger motor units?

This recruitment generally increases force output but also adds to the variability, impacting precision.

Low attention demand=

good secondary task performance

High attention demands

poorer secondary task performance

Parallel processing of sensory information

the ability to process two streams of sensory information simultaneously

See the colour = read the word

no interference in stimulus identification

see the colour ≠ read the word

interference in stimulus identification and response selection

controlled processing =

slow, deliberate, consciously aware, high attention demand

Automatic processing =

fast, smooth, unconscious performance, low attention demands

Arousal def

The level of excitement produced under stress

Inverted U principle

The relationship between arousal level and performance

Individual Zone Optimal Functioning

The range of arousal levels associated with a person’s maximum performance