Week8

Question 1

What is proprioception?

Answer 1

The awareness of the sense of position of body segments in space

Question 2

What is kinesthesia?

Answer 2

The sense of movement

Question 3

What phenomena are encompassed by proprioception?

Answer 3

Sensations related to muscle force and heaviness

Question 4

What are some functions of proprioception?

Answer 4

Allows us to perform accurate movements without continuous visual control, adjust motor control patterns, perform motor tasks that require multi-limb coordination

Question 5

In which disorders is proprioception often abnormal?

Answer 5

Strokes, demyelinating diseases, large-fibre neuropathies (including Guillain-Barré, leprosy), cerebellar disease, dysfunctional states of the central and peripheral nervous system

Question 6

What do Golgi tendon organs respond to?

Answer 6

Increased tension parallel to the extrafusal fibers

Question 7

How do Golgi tendon organs transmit information?

Answer 7

Via group Ib sensory axons to the spinal cord

Question 8

What activates muscle spindle afferents?

Answer 8

Vibration of muscle

Question 9

What does an increase in frequency of muscle spindle discharge indicate?

Answer 9

That the muscle has lengthened

Question 10

What is the effect of proprioceptive illusions?

Answer 10

They can cause incorrect matching of body position, such as the elbow joint angle with the nonstimulated arm

Question 11

What types of joint receptors exist? 2

Answer 11

Free nerve endings, Ruffini endings

Question 12

What do some joint receptors respond to?

Answer 12

Flexion, extension, compression, stress

Question 13

What can joint receptors signal? 3

Answer 13

High joint capsule tension, joint angles close to anatomical limits, joint inflammation

Question 14

What is the dorsal column-medial lemniscal system responsible for? 6

Answer 14

Fine touch, precise perception of location and intensity, vibration, movement against the skin, proprioception, pressure

Question 15

Which areas of the brain are crucial for touch and proprioception?

Answer 15

Primary somatosensory cortex, secondary somatosensory cortex, posterior parietal cortex

Question 16

What is the Pinocchio illusion?

Answer 16

A proprioceptive illusion where the brain perceives the nose as growing when the biceps tendon is vibrated while touching the nose

Question 17

Describe the rubber hand illusion.

Answer 17

A phenomenon where a person feels a model hand as their own when it is stroked simultaneously with their unseen hand

Question 18

What is a key aspect of proprioceptive illusions?

Answer 18

They can produce anatomically impossible perceptions of limb position

Question 19

How does proprioception perform best?

Answer 19

When all mechanoreceptors can contribute

Question 20

Which proprioceptors contribute most at slow speeds?

Answer 20

Muscle and tendon proprioceptors

Question 21

What enhances proprioceptive performance?

Answer 21

Better performance with joint and cutaneous receptors compared to cutaneous only

Question 22

What is the normal gait pattern used by humans?

Answer 22

A symmetrical alternating gait pattern

This gait pattern is characterized by various kinematic factors.

Question 23

How is the velocity of gait defined?

Answer 23

The average horizontal speed of the body measured over one or more strides.

Question 24

Define cadence in the context of gait.

Answer 24

The number of steps per minute.

Question 25

What is step length?

Answer 25

The distance from one foot strike to the foot strike of the other foot.

Question 26

What is stride length?

Answer 26

The distance covered from one heel strike to the next heel strike by the same foot.

Question 27

What does a single limb cycle in gait consist of?

Answer 27

A stance and swing phase.

Question 28

What percentage of the gait cycle duration do adults typically spend in stance and swing?

Answer 28

60% in stance and 40% in swing.

Question 29

What is double support in the context of the stance phase?

Answer 29

The first and last 10% of the stance phase.

Question 30

List the different modes of human locomotion.

Answer 30

* Walk * Race walk * Run * Sprint

Question 31

How does the stance phase duration change with increasing walking speed?

Answer 31

The stance phase becomes shorter in relation to swing.

Question 32

What are the stance phase durations for race walking, running, and sprinting?

Answer 32

* Race walking: 50% * Running: 30% * Sprinting: 20%

Question 33

What are the four phases of the step cycle?

Answer 33

* Flexion (F) * First extension (E1) * Second extension (E2) * Third extension (E3)

Question 34

What is required for stepping in terms of muscle contractions?

Answer 34

A complex sequence of muscle contractions.

Question 35

What preparations are used to study the neural control of locomotion?

Answer 35

* Spinal * Decerebrate * Deafferented * Immobilized

Question 36

Where is rhythmic activity for stepping generated?

Answer 36

Networks of neurons in the spinal cord.

Question 37

Who demonstrated the existence of rhythmic networks in the spinal cord?

Answer 37

Graham Brown in 1911.

Question 38

What happens to muscle contractions after transection of the spinal cord?

Answer 38

Rhythmic alternating contractions of ankle flexor and extensor muscles begin immediately.

Question 39

What is a central pattern generator (CPG)?

Answer 39

A circuit in the spinal cord that generates rhythmic locomotion.

Question 40

How do interneurons in CPGs alternate their activity?

Answer 40

They inhibit each other via another set of interneurons.

Question 41

What is the role of NMDA receptors in CPG mechanisms?

Answer 41

They depolarize membranes and facilitate rhythmic activity.

Question 42

What functions does supraspinal control perform in locomotion?

Answer 42

* Activation of the spinal locomotor system * Integration of feedback from the limbs * Visual guidance of limb movement

Question 43

What happens to the gait and rate of stepping when the MLR is stimulated?

Answer 43

Changes from slowly walking to trotting and finally to galloping.

Question 44

What role does the motor cortex play in locomotion?

Answer 44

Control of precise stepping movements in visually guided walking.

Question 45

What types of sensory input are used by the nervous system to control stepping?

Answer 45

* Somatosensory input * Vestibular input * Visual input

Question 46

How does sensory input from muscle receptors affect stepping?

Answer 46

It regulates the timing and amplitude of stepping.

Question 47

What initiates the swing phase according to sensory input?

Answer 47

Inputs from sensory receptors in muscles that cross the hip.

Question 48

What is assisted-locomotion training?

Answer 48

Training involving a person with a spinal cord injury walking on a treadmill with partial support.

Question 49

How does assisted-locomotion training affect EMG activity in spinal cord injury patients?

Answer 49

It improves EMG activity.

Question 50

What is the basic feature of locomotion?

Answer 50

Alternating phases of swing and stance by each leg.

Question 51

Where do the neural circuits for rhythmic activity in locomotion reside?

Answer 51

In the spinal cord.

Question 52

What specifies the speed and form of locomotion?

Answer 52

A tonic descending signal.

Question 53

What is the role of the cerebellum in locomotion?

Answer 53

Fine-tunes the locomotor pattern by regulating the timing and intensity of descending signals.