Lecture week 6- The cerebellum

Question 1

Main function of the basal ganglia for motor control

Answer 1

Initiation selection of motor programs - cannot test directly

Question 2

Main function of the cerebellum for motor control

Answer 2

Motor coordination and correction - can test directly

Question 3

The 8 motor control parts of the cerebellum

Answer 3

1) maintenance of balance and posture through the vestibular information and proprioception.
2) coordination of multiple muscle groups
3) proprioception input from the muscle spindle and GTO
4) sensory processing
5) adaptability
6) Automaticity: especially to maintain posture
7) motor commands are not initiated in the cerebellum: it modifies motor activity for accuracy

Question 4

Cerebellums role in motor learning

Answer 4

role in adapting and fine-tuning motor programs to make accurate movement through a trial and error process

Question 5

Cerebellums role in cognitive functions

Answer 5

not as well studied as its role in motor system however it does seem to be linked to language

Question 6

the 4 main roles of the cerebellum

Answer 6

1) anticipate the outcome of a motor command in coordination of muscles across several joints
2) Requires proprioception from the muscle spindles
3) Requires vestibular (acceleration, direction, and movement of C spine) for control of balance and equilibrium
4) controls eye reflexed (fixation on target and eye coordination)

Question 7

The accuracy in time of sensorimotor coordination

Answer 7

• Forward model: able to predict the sensory outcome of movements
• able to correct through error based learning
• Timing, on and off patterns of muscle activation, and direction of movement is critical

Question 8

What does input to the cerebellum come from?

Answer 8

vestibular receptors and muscle proprioceptors
- allows for adaptations do shifts in body position or changes in muscle loads

Question 9

what information does the Flocculomodular lobe transport

Answer 9

Vestibular information of equilibrium, balance, and posture

Question 10

what is the main purpose of the lateral hemisphere of the cerebellum

Answer 10

motor planning and initiating movements for extremities

Question 11

what is the main purpose of the intermediate hemisphere of the cerebellum

Answer 11

distal limb coordination

Question 12

what is the main purpose of the vermis and flocculomodular lobe

Answer 12

• Proximal limb and trunk coordination
• Balance and vestibuloocular reflexes

Question 13

What cells are the major output of the cerebellum

Answer 13

purkinje fibers (inhibitory)

Question 14

what cells are the major input to the cerebellum

Answer 14

climbing fibers and mossy fibers
(both excitatory)

Question 15

main cerebellar input pathways (Unconscious input)

Answer 15

• Vestibular input on balance and equilibrium
• Massive motor, sensory, and visual inputs (corticopontine fibers)

Question 16

Inputs from the periphery lower limbs and trunk

Answer 16

1) dorsal spinocerebellar tract (MS)
2) Ventral spinocerebellar tract (GTO)

Question 17

ventral spinocerebellar tract

Answer 17

1b from LE (L2 and below)
information for coordinated movement and posture of teh entire lower limb GTO - unconscious perception

Question 18

Cuneo Spinocerebellar Tract

Answer 18

1a from the UE
Large myelinated axons of primary sensory neurons carry unconscious proprioceptive touch from above C8

Question 19

Rostral Spinocerebellar Tract

Answer 19

1B from UE
information of coordinated movement and posture of the upper limbs (above c8)

Question 20

Dorsal spinocerebellar tract

Answer 20

1A from LE and trunk
Large myelinated axons of primary sensory neurons carrying proprioceptive touch, and pressure sensation from the lower extremities and trunk unconscious perception

Question 21

Inputs from the UE tracts

Answer 21

1) Cuneo spinocerebellar tract (MS)
2) Rostral Spinocerebellar Tract (GTO)

Question 22

Cerebellum outputs

Answer 22

• no direct connection to the motor system
  -output information from the red nucleus to the spinal cord and the VNL of thalamus to the cortex

Question 23

Major origin of input from the pontocerebellar fibers

Answer 23

cortex

Question 24

Major origin of input from the dorsal spinocerebellar tract

Answer 24

Leg proprioceptors

Question 25

major origin of input from the cuneocerebellar tract

Answer 25

arm proprioceptors

Question 26

Major origin of input from the ventral spinocerebellar tract

Answer 26

leg interneurons

Question 27

Major origin of input from the rosteral spinocerebllar tract

Answer 27

arm interneurons

Question 28

main origin of input form the climbing fibers

Answer 28

red nucleus, cortex, brainstem, and spinal cord

Question 29

main origin of input from the vestibular inputs

Answer 29

vestibular system

Question 30

how many times does the ventral SC tract cross

Answer 30

twice

Question 31

how many times does the dorsal, cuneo, and rostral tracts cross

Answer 31

0; they stay unilateral

Question 32

General deficits in cerebellar function

Answer 32

uncoordinated voluntary movements and problems maintaining balance and posture

Question 33

Decomposition of movement

Answer 33

unable to produce coordinated, smooth movements because of the loss of the feedforward mechanism
- does not allow for correct timing of the activated muscle sequence, force or awareness

Question 34

Intension tremor

Answer 34

makes involuntary movement tremor as they approach closer to the target

Question 35

Romberg and sharpened romberg test

Answer 35

a test to check for cerebellar ataxia (back and forward movement)
PT needs to be standing at the side/behind the patient
patient can have feet together, semitandem or tandem

Question 36

what to look for in cerebellar exams

Answer 36

speed, coordination, and timing

Question 37

Dysrhythmia

Answer 37

abnormal timing

Question 38

Dysmetria

Answer 38

overshoot or past pointing

Question 39

Dysdiadochokinesia

Answer 39

rapid alternating movements of pronation and supination

Question 40

Overshooting

Answer 40

holding a testing postion and suddenly letting go

Question 41

types of cerebellar tests

Answer 41

finger to nose, heel to shin, dysdiachokinesia, tandem walking, Romberg, rapid finger tapping movements