1. What are Motor systems
Help control movement and behaviors
2. How are motor and sensory neurons interlinked?
They are closely connected and hard to separate since behavior
is continuously motivated and guided by sensory input. Muscles
have sensory endings (muscle spindles) that detect changes in
muscle stretch and send feedback to nervous system
3. What are the 3 general classes of movement
Reflex (doesn’t need cortex)
Rhythmic movement (repeated cycles walking, breathing) doesn’t
need cortex
Voluntary (require cortex)
4. Describes hierarchical vs parallel control in motor
systems
Hierarchical control is top-down (brain to muscle)
Parallele control involves multiple pathways (redundancy)
allows flexibility and stability in movement control
5. What is feedback and feedforward and role in motor control?
Feedback: adjusts movement in response to sensory input
Feedforward: control anticipated movement needs
Both ensure smooth and accurate action
6. How could you identify neurons responding for a specific
movement
Anterograde (soma to axon) tracing
Retrograde tracing (axon to soma)
In vitro: isolate tissue under controlled conditions
In vivo: real-time neuronal response and interactions during actual
movement
Optogenetics: light to control neurons that have been genetically
modified to respond to specific light wavelengths
Calcium imaging: visualizes calcium levels in neurons, rising
when neuron is active
fMRI & PET scan: measure brain activity and energy use,
highlight brain regions active during movement.
7. Significance of skeletal muscles in movement?
They enable voluntary movements with agonists muscles
opposing and synergist muscles assisting primary action
8. Extrafusal and intrafusal muscle fibers
Extrafusal fibers: main muscle fiber for force and movement,
innervated by alpha motor neurons
Intrafusal: specialized fibers in muscle spindles that detect
stretch, innervated by gamma motor neurons
9. Define lower motor neurons and their types
Lower motor neurons, include alpha, gamma neurons, and local
interneurons, directly activate muscle fibers and are organized by
function and body region
10. What is a motor unit, and how does it influence
movement?
Motor units: smallest functional unit in motor system, consisting of
a motor neuron and muscle fiber. More movement force = more
firing, unit recruitment, and fast-fatigable units
11. What is size principle in motor unit recruitment
Motor units are recruited from small (slow) to large (fast) as force
increases, optimizing energy use and control
12. What role do Ia afferents play in motor circuits
Afferents of reflex circuit is Ia fiber in the muscle spindles which
detect stretch and send info to spinal cord (ex: myotatic stretch)
13. Explain myotatic (stretch) reflex with an example
Involves muscle spindle activation upon stretch leading to muscle
contraction, helping maintain posture
14. What is flexor reflex
Reflex allow withdrawal from painful stimuli, where flexor muscles
contract and extensors relax t protect body from harm
15. Function of gamma motor neurons
Adjust muscle spindle sensitivity for dynamic range and control,
so spindles cna accurately signal changes in muscle length
16. What info do golgi tendon organs provide
Sense muscle contraction force, preventing muscle damage by
inhibiting excessive tension
17. What are central pattern generators (CPG) is locomotion?
CPG are spinal circuits that produce rhythmic movement (walking,
talking) without sensory input, crucial for repetitive motions in
locomotion
18. Why are simpler model systems used in locomotion
studies
Model systems, like simpler animals, allow easier study of motor
rhythms since neurons are fewer, larger, and easier to observe
19. Antagonist vs Synergist muscles
Antagonist muscles: inhibited to allow movement of agonist’s
muscle
Synergist muscles contract & assist agonist muscles for
movement (ex: soleus and gastrocnemius muscles)
20. Local circuit neurons
In the spinal cord, provide coordination between muscle and give
most inout to LMN
21. What is Somatatopically organized
Arrangement of motor neurons in spinal cord, medial neurons
controlling trunk and proximal muscles. Lateral neurons control
distal muscles
22. Recruitment order
Order in which motor units are activated based on force
23. Motor unit ‘plasticity’
Motor units adapt based on use
Ex; sprinters develop fast, fatigable fibers for power, marathon
runners develop slow, fatigable resistant fibers for endurance