Control of movement

Question 1

What are cognitive inputs?

Answer 1

These are there to understand what we want to do (relation to emotional and psychological).

Question 2

What is proprioception?

Answer 2

This is sensory info that tells us where our limbs are in space.

Question 3

What is the point of sensory (proprioceptive) feedback?

Answer 3

Make sure the movements we are making are appropriate.

Question 4

Which propriceptors send info through the spinocerebellar pathway?

Answer 4

Muscle spindles (muscle length) and Golgi tendon organs (tension in muscles).
These dont reach the cortex (unconscious).

Question 5

Which proprioceptors send info though the dorsal column pathway?

Answer 5

Pacinian corpuscle (pressure and vibration), Ruffini endings (tension stretch), kinaesthetic receptors (limb position and change).
These reach the cortex.

Question 6

Does the spinocerebellar pathway decussate?

Answer 6

No.

Question 7

What is proprioceptive deafferentation?

Answer 7

Loss of proprioception, can’t travel/ gain the afferent sensory info to the CNS (have to use sight to use limbs).

Question 8

What is the purpose of the somatosensory cortex?

Answer 8

Early cognition.

Question 9

Purpose of primary motor cortex?

Answer 9

Initiation of motor control.

Question 10

Purpose of pre- motor cortex?

Answer 10

Developed patterns of movement.

Question 11

Purpose of basal ganglia?

Answer 11

Scaling and action selection.

Question 12

Purpose of cerebellum?

Answer 12

Refinement of motor control.

Question 13

Purpose of brain stem nuclei?

Answer 13

refinement of motor control.

Question 14

Purpose of spinal cord?

Answer 14

Spinal reflex loops (require proprioceptive info).

Question 15

Where is the vestibular system?

Answer 15

Part of the inner ear.

Question 16

How can the vestibular system sense the acceleration of movement?

Answer 16

Embedded in the bone of head so going to move when the head moves (can measure movements of the head).

Question 17

Ball bearing and box model?

Answer 17

When the box is shaken with the ball bearing inside, the ball bearing moves a different way to the box as it has inertia so tries to stay still.

Question 18

What are the features of the vestibule system?

Answer 18

-Vestibular nerve
-Scarpas ganglion
-Semi- circular canals
-Otolith organs (utricle and saccule).

Question 19

What is scarpas ganglion?

Answer 19

Series of nerve cell bodies receiving from canals and otolith and passing to the nerve and brain.

Question 20

How do otolith organs function as accelerometers?

Answer 20

The hair cells are embedded in support cells. These hair cells have stereo cilia that are embedded in a gel that have otoliths. These otoliths have inertia and so when movement occurs, they move the opposite way.

Question 21

Which way do stereo cilia move to be negatively charged?

Answer 21

Stereocilia move away from the kinocilium (hyper polarise).

Question 22

Which way do stereo cilia move to be positively charged?

Answer 22

Stereocilia move towards the kinocilium (depolarise).

Question 23

What is the purpose of ampullae?

Answer 23

The cilia is inside the endolymph (fluid), when shaken, cilia moves and deflects the hair cells.

Question 24

What are the 4 main targets of the vestibular nuclei?

Answer 24

-Eye muscles (where they move in comparison to head)
-Cerebellum (perfect/ smooth movements- embed info about how body needs to react).
-extensor LMNs (balance and posture)
-Cervical spinal cord (adjustment of head and awareness of how to control muscles of the neck).

Question 25

What are problems due to vestibular apparatus damage?

Answer 25

-Dizziness (Deterioration of input) -balance disorders -lack of coordination (no input to cerebellum -bouncing vision (no input to oculomotor nuclei).

Question 26

What is the dorsal visual stream?

Answer 26

stream of info from occipital lobe to sensory associative areas.

Question 27

What is the ventral visual stream?

Answer 27

Stream of info from the insula and temporal lobe memory areas (not as important effect on motor control- do I recall or remember this?)

Question 28

What happens if you have loss of visual sense?

Answer 28

-loss of a major proprioceptive sense -reliance on other proprioceptive modalities -much more severe difficulties if other senses impaired.

Question 29

Role of basal ganglia and cerebellum in the control of movement model?

Answer 29

These monitor what's happening and adjust motor programmes (no control of interneurons- just interact in 2 way feedback to monitor).

Question 30

What is the purpose of the basal ganglia?

Answer 30

-Scaling (how big the movements are) -Action selection (selecting appropriate actions to situation. They also inhibit inappropriate movement (receive info from all sensory and motor and feedback to motor area)

Question 31

What is the amygdala?

Answer 31

Relation to emotional understanding of threats.

Question 32

What is the direct pathway for basal ganglia?

Answer 32

Pathway where the desired behaviours are passed back to the cortex (promoted)

Question 33

What is the indirect pathway for the basal ganglia?

Answer 33

Pathway that inhibits undesired pathways (decides that programme is inappropriate).

Question 34

What is the function of the substantia nigra?

Answer 34

Facilitates direct pathway and inhibits inappropriate motor commands (overall facilitation of movement).

Question 35

What NT does the substantia nigra produce?

Answer 35

Dopamine.

Question 36

What happens if dopamine stops being produced from the substantia nigra?

Answer 36

Scaling of movement is affected (difficult to initiate movements of the body- Parkinsons).

Question 37

What is L-DOPA?

Answer 37

This can be given as medication and it is converted to dopamine in the brain- needed to make scaling more appropriate (after taking, walk better and swing arms etc).

Question 38

How do basal ganglia influence motor activity?

Answer 38

-Action selection (facilitate/ suppress movement) -Establish background patterns of movement -Control and adjust posture -Regulate scale/ intensity of motor output.

Question 39

What is the function of the cerebellum?

Answer 39

This receives both sensory and motor and has a regulatory role (not directly contacting the LMNs).

Question 40

What are the functional divisions of cerebellum?

Answer 40

-Vestibulocerebellum (from vestibular nuclei- balance) -Spinocerebellum (posture, muscle tone, input from proprioceptors and output to motor centres in brain stem) -Corticocerebellum (coordination and motor learning, input from motor cortex and output to motor cortex via thalamus).

Question 41

What impact does the cerebellum have on motor control?

Answer 41

Compares what we want to do vs what we actually do (proprioceptors tell us where arm actually is and cerebellum can readjust until the goal is achieved).

Question 42

What happens is there are cerebellar lesions?

Answer 42

-problems with balance and posture -ataxia -asynergia -dysmetria -scanning speech -decomposition of movement

Question 43

What is ataxia?

Answer 43

Abnormal or uncoordinated movements

Question 44

What is asynergia?

Answer 44

Difficulty creating fluid motions

Question 45

What is dysmetria?

Answer 45

Undershoot or overshoot- can't judge scale of movements.