Section 5b

Question 1

what is the Basel ganglia and what does it connect to?

Answer 1

it is a collection of nuclei that sit deep in the middle of your brain and it has connections to the thalamus

Question 2

what are the 5 nuclei of the Basal gangila?

Answer 2

• Caudate nucleus and putamen (together called striatum)
• globus pallidus:
• substantia nigra
• subthalamic nuclei

Question 3

what are the 4 circuits that involve the Basal ganglia and what do they do?

Answer 3

• motor loop: motor movement
• oculomotor loop: eye movement and frontal field
• prefrontal loop: decision making
• limbic loop: emotions

Question 4

what is the motor loop connection to?

Answer 4

involves the primary motor and pre motor cortex

Question 5

what does the prefrontal loop connected to?

Answer 5

dorsolateral prefrontal cortex

Question 6

the medial pathway has basic postrual control of the…

Answer 6

axial and proximal muscles (core/trunk and closer to centre of body)

Question 7

what are the 4 major descending brainstem pathways?

Answer 7

• vestibulospinal tract
• reticulospinal tract
• tectospinal tract
• rubrospinal tract

Question 8

what are the 3 tracts controlled by the medial pathways of the brainstem?

Answer 8

• vestibulospinal
• reticulospinal
• tectospinal

Question 9

what does the lateral pathways do?

Answer 9

they have muscle control of the more goal directed limbs

Question 10

what is the tract controlled by the lateral pathway of the brainstem?

Answer 10

• rubrospinal tract

Question 11

what does the reticulospinal control and what’s its origin in brain?

Answer 11

reticular foramen
- maintain posture and muscle tone in extensor muscles

Question 12

what does the vestibulospinal control and what’s its origin in brain?

Answer 12

vestibular nuclei
- control posture and orientation of head and body in space

Question 13

what does the tectospinal control and what’s its origin in brain?

Answer 13

superior colliculus
- head and eye movements

Question 14

what does the rubospinal control and what’s its origin in brain?

Answer 14

red nucleus
- excitatory influence on the motorneurons on the proximal upper limb flexors

Question 15

what region controls the initiation of walking and hoq

Answer 15

MesLR (Mesencephalic region of the brain)
- it is connected to the reticular foramen and uses the reticulospinal tract to trigger the CPG
- the cerebellum and the motor cortex also contribute

Question 16

what does the cerebellum do and what volume of the neurons does it contain?

Answer 16

makes movement smooth, regulate the eye movements and maintains balance, has half the brains neurons while only being 10% of the volume.

Question 17

what does the cerebellum contain??

Answer 17

contains the
- vestibulocerebellum
- spinocerebullum
- cebrocerebellum

Question 18

what does the vestibulocerebellum do?

Answer 18

receives visual and somatic sensory from the neck to return it to the vestibular nuclei

Question 19

what does the spinocerebellum do?

Answer 19

receives somatic sensory from the trunk and limbs, visual and auditory and sends it to the origins of the rubospinal, recticulopsinal and vestibulospinal tract

Question 20

what does the cerebrocellum do?

Answer 20

receives information from the association cortex

Question 21

what are the disorders called when cerebellum is damaged and what’s the issue?

Answer 21

dysmetria- abnormal trajectories
dysdiadochokinesis- abnormal rapid movements (clapping)
gait ataxia- slow, “drunk” walk

Question 22

what are the cortical areas of the brain?

Answer 22

• posterior parietal cortex (most important)
• premotor cortex
• supplementary motor area
• primary motor cortex

Question 23

what does the posterior parietal cortex (PPC) control?

Answer 23

helps sensory integration and planning and control of motor movements

Question 24

what evidence supports that the PPC is involved in motor planning?

Answer 24

with of without a memory component in the memory-delay task (or delay task) the PPC is active in during the delay and as a preferred direction is goes towards

Question 25

example of evidence that PPC is active in planning

Answer 25

different groups of neuron activate before activity like - set advanced neurons in area 5 activate before a cat steps over the obstacle

Question 26

what are the sub sections of the PPC?

Answer 26

- parietal eye field - parietal arm field - parietal grasp field - parietal face field - partial foot field

Question 27

why is the delay period in the studying of motor planning important

Answer 27

the delay period allows researches to see which neuron receives to the cue, plans the movement and executes the movement

Question 28

what does the supplementary motor area do?

Answer 28

involved in the motor planning uses internal cues (memory)

Question 29

what does the premotor cortex do

Answer 29

involved in the motor planning using external cues - the neurons are active during the planning portion of the memory delay task as well

Question 30

how is the primary motor cortex involved in motor planning

Answer 30

it is involved in coarse movements because the neruons are organized by behaviour since multiple joints and muscles are involved in simple movements - direction of movement - adapting to new conditions

Question 31

explain population coding (in primary motor cortex)

Answer 31

motor cortex neurons each have a preference in direction. To determine the actual direction of movement, you have to find the vector sum of all the neurons activated. We know this exist because there is more activity when moving in that direction

Question 32

how does the cerebral cortex modulate the activity of the brainstem and spinal cord

Answer 32

- corticobular fibres control the motor nuclei in brainstem - corticospinal fibres control the motor neurons that innervate the trunk and limb muscles

Question 33

show (with supporting evidence) how spinal, brainstem, and cortical centres work together to plan and guide walking

Answer 33

- The MesLR initiates walking causing the CPG in the spinal cord to activate the flexor and extensor circuits - the sensory feedback from the muscle spindles, GTO and cutaneous receptors alter the signal that the MesLR sends to the CPG to modify walking

Question 34

What is the supporting evidence that the spinal cord, brainstem and cortical centres work together?

Answer 34

when connection to MesLR in brain is severed from CPG, initiation of walking is not possible however - when the hindlimbs are oscillated to extension of hip activity in the motorneuron is shown and leg is swug. when flexed, it ceases. - when hip flexion is manipulated to occur while extension is happening, the extension neurons stop activating to allow flexors