L8, Motor Control

Question 1

What are 4 ways in which we can study action/motor?

Answer 1

1. behaviourally (video or electric equipment to record body parts in time and place)
2. muscle physiology (electromyography, measuring electrical activity in muscles)
3. single unit electrophysiology (implantation of electrodes in the brain and measuring their activity.
4. Neuroimaging (EEG, fMRI)

Question 2

Explain the anatomy of a muscle

Answer 2

A muscle is a collection of muscle fibres. The muscles are organised in antagonistic pairs with extensors extending the joint, and flexors contracting the muscle. Muscle spindles and Golgi tendon organs provide proprioceptive information from the muscles.

Question 3

How does muscle contractions work? (in terms of neuroscience)

Answer 3

Motorneurons release neurotransmitters to cause muscle contraction at the neuromuscular junction. The neurotransmitter acetylcholine binds to inotropic receptors, causing depolarization. Enough depolarisation will open the voltage-gated ion channels allowing the inflow of calcium, causing actin and myosin proteins to interact, bringing about a muscle contraction. Acetylcholinesterase removes the neurotransmitter and ends the contraction.

Question 4

Where are motor functions controlled?

Answer 4

The primary motor cortex but some muscles are controlled by the cranial motor nuclei in the brainstem, sending axons to directly innervate muscles of the head and neck. All other muscles need the brain to send signals to the spinal cord via the pyramidal system or the corticospinal system.