control of movement

Question 1

what are the basal ganglia?

Answer 1

• group of nuclei deep inside the brain

- taking information comping up from the body and integrating it with information from higher parts of the brain

Question 2

different levels of processing in…

Answer 2

…movement control

Question 3

basal ganglia function?

Answer 3

• take information from multiple cortical and brainstem region (not just areas involved in movement also areas involved in emotion, cognitive function), integrates it with higher regions of the brain and outputs to selected areas
• focussing function

Question 4

name a basal ganglia degenerative disorder?

Answer 4

parkinsons

Question 5

how are the basal ganglia segregated?

Answer 5

they are segregated anatomically between different loops (motor, associative, limbic)
-and also within loops (eg. motor, topographic separatioN)

Question 6

is the main output of the basal ganglia inhibitory or excitatory?

Answer 6

inhibitory

-more activity of the basal ganglia= less movement

Question 7

what pathways exist through the basal ganglia?

Answer 7

• one which decreases output activity (increases movement)

- one which increase output activity (decreases movement)

Question 8

which neurotransmitter promotes movement?

Answer 8

dopamine

Question 9

which part of the brain produces dopamine

Answer 9

substantia nigra

Question 10

the change in firing rate of the output nuclei determines what?

Answer 10

determines the degree of thalamic inhibition and therefore the amount of movement possible

Question 11

what is bradykinesia?

Answer 11

lack of movement

Question 12

what is parkinsons

Answer 12

• basal ganglia degenerative disorder
• the substantial nigra degenerates, so no dopamine
• dopamine turns on movement pathway and turns off non-movement pathway
• thalamus and motor cortex inhibited

Question 13

symptoms of parkinsons

Answer 13

• clinically dominated by bradykinesia
• tremor in left hand
• slower movements

Question 14

what is Parkinsons clinically dominated by?

Answer 14

bradykinesia

Question 15

hyperkinesia?

Answer 15

muscle spasm - too much movement

Question 16

what is hemiballismus and what is it caused by?

Answer 16

flinging movement of 1 side of the body, jerking

-caused by sub-thalamic nucleus stroke, which means the inhibitory input of basal ganglia turns down

Question 17

subthalamic nucleus is key in?

Answer 17

stopping movement, sends signals to stop the thalamus and motor cortex

Question 18

beta activity and movement - whats the relationship and how can it be used clinically?

Answer 18

suppression of beta activity is associated with better movement control
-levodopa is a parkinsons drug that acts by suppressing beta

Question 19

what suppresses beta?

Answer 19

deep brain stimulation surgery

Question 20

what happens before movement?

Answer 20

there is a baseline dopamine release before movement

Question 21

how do drugs affect phasic dopamine release?

Answer 21

they increase it

Question 22

what is beta release like in parkinsons and how can it be treated?

Answer 22

• parkinsons has pathologically high beta release

- levodopa is a parkinsons drug that acts by suppressing beta

Question 23

what happens to beta power just before you move?

Answer 23

beta power goes down

• basal ganglia getting ready to destabilise the state you’re in to allow the cortex to let a new movement happen
• after the movement is finished, beta power goes up and stabilises at a new state

Question 24

what does the cerebellum compare?

Answer 24

compares what happened with what you expected to happen

Question 25

what gives info to motor control?

Answer 25

lots of different brain regions