Lecture 9 - Motor pattern generation (1)

Question 1

How is rhythmic output generated, coordinated, and controlled by the nervous system?

Answer 1

• Contractions of numerous muscles
• Posture
• Adjustments to unpredictability
• Sensory feedback
• Proprioceptive feedback

Question 2

What does stepping require? [2]

Answer 2

• Intravenous L-Dopa

- Electrical stimulation of mesenscephalic locomotor region

Question 3

How does the central pattern generator work?

Answer 3

Work by providing both flexor and extensor with a signal for rhythmic movement

Question 4

How does the chain of reflexes work?

Answer 4

• Movement within flexor sends relfex to the extensor causing it move
• A cycle of reflexes happen to ensure rhythmic movement

Question 5

List two other forms of movement in animals that are rhythmic movements? [2]

Answer 5

• Dogfish swimming

- Flight in locust

Question 6

How can you study the circuitry and pharmacology of spinal rhythm generation in rats?

Answer 6

• Recordings from ventral nerve roots

- Induce rhythm by bath application of serotonin and NMDA

Question 7

How do fictive behaviours compare to real behaviours?

Answer 7

• Do not mirror the real thing

- Cycle frequency is often slower

Question 8

What are the levels of the motor control hierarchy?

Answer 8

> Higher order control centres
Premotor network (CPG)
Motor neurons

Question 9

What creates the alternating activity for flexors and extensors in the motor control hierarchy?

Answer 9

The premotor network (CPG)

Question 10

What is the central pattern generator?

Answer 10

A premotor network of neurons that imposes rhythmic activity on motor neurons

Question 11

What does the output pattern of the central pattern generator depend on? [3]

Answer 11

• Intrinsic properties or neuronal components
• Synaptic interactions
• Network configuration

Question 12

What does reconfiguration of the central pattern generator cause?

Answer 12

Different output patterns (walking/running)

Question 13

What are the five intrinsic membrane properties of central pattern generator neurons? [5]

Answer 13

• Excitability
• Endogenous bursting
• Spike frequency adaptation
• Post-inhibitory rebound
• Plateau potentials

Question 14

What are the properties a synapse needs for rhythm generation?

Answer 14

• Polarity: excitatory vs inhibitory
• Electrotonic vs chemical
• Time course
• Neuromodulatory synapses
• Short term plasticity

Question 15

What are the two types of network configurations for rhythm generation? [2]

Answer 15

• Reciprocal inhibition (x-y)

- Recurrent inhibition (x-y-z): Allows for 2-phase cycle

Question 16

What are the two oscillators that can help generate rhythm?

Answer 16

• Network oscillator

- Pacemaker-driven oscillator

Question 17

What network configuration determines the swimming in Clione?

Answer 17

Reciprocal inhibition