11 Movement

Question 1

How do voluntary movements occur?

Answer 1

Skeletal muscles are activated by motor neurons from the spinal chord which release ACh into the neuromuscular junction when polarised. ACh then leads to Ca2+ to be released which leads to contraction by opening up the actin filaments for myosin to slide in.

Question 2

Example of single synapse reflex and why it occurs?

Answer 2

Stretch reflex (knee jerk): 
Occurs to constantly adjust muscle tension in activities such as walking 

Involves:
Afferent input from muscle spindle (which detects muscle stretches)
Efferent output to thigh muscle (contracts the muscle)
Afferent input from Golgi tendon organ (detects extreme tendon stretching that inhibit efferent output via a gabonergic interneuron)

Question 3

What is myasthenia gravis?

Answer 3

An autoimmune disease which attacks the ACh receptors of neuromuscular junctions. This stops the ability for muscle contraction to occur over longer periods of time and is experienced as fatigue by those with the condition.

The video showed during the lecture showed that the man was able to do squats at first but then got weak and soon collapsed way faster than the average person

Question 4

What are central pattern generators and where are they located?

Answer 4

They are specific spinal chord circuitry that control sequential movements such as breathing and to some extent walking

Question 5

Origins of descending motor control and function of each

Answer 5

Brainstem - controls muscles of trunk, neck and proximal limbs. Controls posture and corrects balance

Red nucleus - controls the independent movement of limbs

Motor cortex - control muscles in arms, hands and fingers. Voluntary manual movements

Question 6

What motor dysfunction can occur after damage to the internal capful after a stroke?

Answer 6

Hemiparesis and hemianaesthesia

Question 7

What is known about the coding of movement in the motor cortex?

Answer 7

The premotor area and supplementary motor cortex fire the anticipated direction or destination of movement.
This was seen in the monkey joystick experiment + the anti clockwise clock experiment

Question 8

How is the cerebellum related to cognition?

Answer 8

Cognitive impairments similar to that in the Fcortex are seen in Cb damage (EF deficits )

There also seems to be specific activation of Cb hemispheres during cognitive tasks.
Right Cb is activate more when subjects are told to generate a verb in response to seeing a noun, more than just reading the noun + when they are to think about the semantic meaning of a word rather than just making up a word that rhymes
Left Cb becomes more active when subject are told to make a lie