Locomotion and propreoception

Question 1

1. What is gait?

Answer 1

a. Repeating sequence of leg movement
b. Quadrupeds have 4
c. Each gait change how limbs move to give faster or slower pace
d. Repeating sequence set by group of neuroens in spinal cord called central pattern generator
e. Higher centres needed to initiate gait and refine, terminate as move but rhythmic movement = all spinal cord = keep happening until higher centres tell ti otherwise

Question 2

2. What determines speed?

Answer 2

Speed = stride frequency x stride length

Question 3

3. Name different gaits:

Answer 3

a. Walk, pace, trot, gallop

Question 4

4. What is proprioception?

Answer 4

a. A SENSE
b. AFFERENT information
c. Sensory input
d. Sense of the relative position of the body parts, whether moving and HOW they are moving
e. Used by the brain to integrate and influence motor output
f. Ensures posture is appropriate so you can maintain balance and position in the world

Question 5

6. What receptors does proprioception rely on and what do they tell the brain?

Answer 5

a. Proprioceptors
b. Inform CNS of body position, strength, speed etc so motor output can be modified as needed
c. Msucle spindles
d. Golgi tendon organs
e. Joint receptors = how bent and loaded joint
f. Skin receptors
g. Skin tactile and mechanoreceptors
h. Vestibular system
i. Hair cells

Question 6

7. What is key to remember with regards to proprioception and motor function? And why?

Answer 6

a. An animal can only demonstrate normal proprioception if have normal motor function
b. Can’t ask
c. P = only an input, it doesn’t imply awareness of it
d. When examining animal, can’t tell if know where legs are, unless putting legs in correct place which they can’t do if good motor function

Question 7

8. What are the types of proprioception?

Answer 7

a. Conscious

b. Subconscious

Question 8

9. What is conscious P to do with

Answer 8

a. Awareness of specific fine detail
b. Voluntary
c. 3 neurone system

Question 9

10. What is sub conscious P to do with

Answer 9

a. Rhythmic movements, subconscious

b. 2 neurone system

Question 10

11. How are conscious dan sub conscious P different anatomically?

Answer 10

a. Sub = 2 neurone system

b. Conscious = 3 and ends in somatosensory conscious for you to be conscious for it

Question 11

12. Conscious deficits

Answer 11

a. Stumbling, knuckling, intention tremor (animal tried to do something but can’t reach target)

Question 12

13. What is the anatomy of conscious proprioception

Answer 12

A 3 neuron system

a. Proprioceptor
b. Sensory neurone synpase in dorsal root ganglion
c. 2nd neurone to thalamus
d. 3rd neurone from T to contralateral somatosensory cortex (decussates)
e. Means that info on fine movement on LHS goes to right somatosensory cortex

Question 13

14. If animal lesion of left somatosensory cortex what conscious proprioception deficit signs might you expect?

Answer 13

a. Errors on RHS
b. Stumble, put foot wrong way up
c. Broadly will be able to navigate its way around the room.

Question 14

15. What is subconscious proprioception?

Answer 14

a. Rhythmic, innate, basic things you don’t think about: sitting, standing, scratching, chewing locomotion
b. Used to set postural platform (right way up)
c. Poor = stagger around, fall over, struggle to maintain appropriate strength
d. 2 neurone system
e. Input from head cranial nerves 5 and 8

Question 15

16. What is the anatomy of subconscious proprioception?

Answer 15

2 neuron system

a) Proprioceptors stimulate receptor and an axon with its cell body in a spinal ganglion (dorsal root ganglion)
b) second neuron runs as the spinocerebellar pathway bilaterally in the lateral funiculi of the spinal cord to the ipsilateral cerebellum. stays on same side.
c) Input from the head comes via cranial nerves V and VIII.

Question 16

17. Abnormalities/ deficits in sub conscious proprioception:

Answer 16

a. Called ataxia
b. Defined as alteration in the rate, range and force of movement
c) become inappropriate (too far/ not far enough, too strong of weak)
d. Swaying of trunk, wide base stance, cross legs, odd gait
e. May be a Non intention tremor = tremor occurring at rest as muscles can’t stabilise around a joint as body can’t tell where they are.

Question 17

18. Animals with lesion on left cerebellum, what subconscious proprioception deficits might you expect?

Answer 17

a. Signs on LHS
b. Un coordination – feet in wrong place
c. Cross legs over
d. Fall over
e. ataxia: swaying trunk, wide base stnace, non intention tremor

Question 18

19. Spinal tracts

Answer 18

a. Conscious P largely in dorsal funiculus
i. CP hindlimb = most medial part of this funiculus = Gracile fasiculus
ii. Thorax and thoracic limb = cuneate fasiculus = more lateral part of dorsal funiculus

Question 19

20. If lesion affecting the dorsal funiculus ONLY what would you expect to find and why?

Answer 19

a. Conscious P deficits for everything caudal to the lesion

b. Because tracts can’t travel forward

Question 20

21. Location of subconscious tracts

Answer 20

a. Lateral funiculus = spinocerebellar tracts (up spinal cord to cerebellum)

Question 21

22. If injury to lateral spinal cord what kind of proprio deficit would you expect as why?

Answer 21

a. Sub conscious as the sub conscious proprioceptors are located in the lateral funiculus = spinocerebellar tract

Question 22

23. What is Kinaesthesia?

Answer 22

a. Awareness of position of the movement of the body

b. Rather than just fact the input is happening

Question 23

24. How does kinaesthesia happen?

Answer 23

a. Info going into cerebellum from the subconscious proprioception ahs to go to the contralateral somatosensory cortex
b. Does by decussating
c. So although sub conscious P info goes to ipsilateral cerebellum it DECUSSATES to contralateral side for you to be aware of it
d. So to be functionally effective of the movement = only have to stay on one side
e. But to be aware it must decussate

Question 24

25. What type of proprioception is the cerebellum involved in?

Answer 24

a. Sub conscious
b. Comparing intended movement with actual
c. Input from muscle tendons, golgi, vestibular etc

Question 25

26. Where is the location of the vestibular cerebellum and what goes it coordinate

Answer 25

a. Bottom bit tucked under cerebellum

b. Balance and eye movement

Question 26

27. Where is location of spinocerebellum

Answer 26

a. Middle bit

b. Coordinates muscle tone and movement, general movement, posture

Question 27

28. Where is location of cerebrocerebellum?

Answer 27

a. Lateral hemispheres

b. Planning of movement

Question 28

29. Dog presents with: swaying, stumbling, deficits in awareness of body, strange gait, normal cranial nerve test, normal reflexes in all 4 limbs, deep pain sensation in all 4 limbs. Where might lesion be?

Answer 28

a. Spinal cord

b. All limbs affected so lesion must be in cervical spine somewhere