Supraspinal control

Question 1

Motor pathways

Answer 1

Corticospinal and rubrospinal - lateral pathways - voluntary fine movement of limbs + fingers.
Vestibulospinal and tectospinal - vertical.

Question 2

cortical mapping

Answer 2

Mapping in motor cortex isn’t precise, lot of overlap or convergence in corticospinal projections.

Question 3

Divergence

Answer 3

A single corticospinal projects widely

Question 4

Muscle force in M1 neurons

Answer 4

M1 output neurons - firing rate correlates with force of contraction.

Question 5

Premotor cortex

Answer 5

PM projects to motor cortex.
PM is involved with planning movements based on external cues eg visual.
Supplementary Motor Area is involved with planning based on internal cues.

Question 6

Movement planning

Answer 6

M1 and somatosensory are active during finger movements.
SMA and M1 and S1 are active during executiong of specific sequence of finger movement.
SMA is active during mental regearsal.

Question 7

Cerebellum

Answer 7

10% brain volume
>50% total brain neurons

Question 8

Cerebellar cortex and Cerebellar nuclei

Answer 8

cortex - huge number of neurons
nuclei below cortex - recieve input from cortex, send output to other part of motor system.

Question 9

Cerebellar lesions

Answer 9

Cerebellar injury - ataxia - loss of coordination and movement. SLurred speech, poor fine motor skills, gait abnormalities.

Question 10

Theories of cerebellar control

Answer 10

Cerebellum receives copies of movement plans from other structures.
External feedback from sensory input.
Adjusts motor outputs for fine movement
‘learns’ from feedback and predicts

Question 11

Basal ganglia

Answer 11

When damaged, parkinsons, huntingtons arise. Pathways from BG lead to SMA.
Dopamine initiates movement - D1 receptors in direct Basal ganglia pathway, dopamine activates motor activation.
D2 receptors in inhibitory pathway - dopamine antagonist effect, so inhibitory pathway is inhibited - results in movement.