spinal reflexes and cpg

• What are the two types of movement described in the study material?

  Voluntary and involuntary movement
• What controls voluntary movement?

  Higher motor areas
• What are the two types of motor neurons involved in voluntary movement?


  Upper and lower motor neurons
• How is involuntary movement evoked?


  From peripheral stimulation
• What is the role of spinal reflexes?


  To couple sensory input to motor output
• What is the myotatic reflex also known as?


  The knee jerk reflex
• What happens during the myotatic reflex when a tendon is tapped?


  The muscle contracts to restore its length
• What is the primary function of the myotatic reflex?


  To prevent overstretching of the muscle
• What type of reflex is the myotatic reflex in reality?


  A polysynaptic reflex
• What role do inhibitory interneurons play during the myotatic reflex?


  They relax the antagonistic muscle
• What is reciprocal innervation?


  Coordination of agonist and antagonistic muscles
• What do cutaneous receptors detect in the flexor withdrawal reflex?


  Noxious stimuli
• What happens to flexor and extensor muscles during the flexor withdrawal reflex?


  Flexor muscles contract while extensor muscles relax
• What is the purpose of the crossed extensor reflex?


  To maintain balance while removing the ipsilateral limb from painful stimuli
• How do interneurons function in the crossed extensor reflex?


  They cross the spinal cord to act on opposite leg muscles
• What types of afferents are associated with muscle spindles?


  Ia and II afferents
• What inputs do motor neurons receive?


  Sensory input from muscles and input from upper motor neurons
• What is the jendrassick manoeuvre used for?


  To heighten lower limb tendon reflexes
• What is fictive locomotion?


  Generation of locomotor patterns in the absence of real movement
• What is the half-centre hypothesis?


  It describes two neuronal centres that inhibit each other to produce rhythm
• What are pacemaker neurons responsible for?


  Creating continuous rhythmic movements
• How do neuromodulators affect CPGs?


  They change the output of CPGs to create different movements
• What can experimental evidence suggest about higher centres and CPGs?


  Higher centres can change patterns of activity
• What happens when dopamine lesions occur in the basal ganglia?


  They lead to deficits in locomotion initiation
• How is bipedal locomotion different from quadrupedal locomotion in humans?


  Bipedal locomotion is more complicated
• What implication does the study suggest for spinal cord injury?


  Retraining circuits can restore function
• What are the key components of voluntary and involuntary movement?


  • Voluntary movement:
  • Controlled by higher motor areas
  • Involves upper and lower motor neurons
  • Involuntary movement:
  • Evoked from peripheral stimulation
  • Involves spinal reflexes
• What are the types of reflexes and their functions?

  • Myotatic reflex:
  • Monosynaptic
  • Restores muscle length
  • Prevents overstretching
  • Flexor withdrawal reflex:
  • Detects noxious stimuli
  • Rapidly removes limb from danger
  • Crossed extensor reflex:
  • Maintains balance during withdrawal
• What are the roles of proprioceptors and muscle spindles?


  • Proprioceptors detect body position and movement.
  • Muscle spindles:
  • Detect stretch and rate of change
  • Synapse onto motor neurons
• What is the function of central pattern generators (CPGs)?


  • Generate rhythmic movements without sensory input
  • Involved in various locomotor patterns
  • Can be modified by descending control
• What is the significance of the half-centre hypothesis in rhythmic movement generation?


  • Two neuronal centres inhibit each other
  • Capable of producing basic rhythm
  • Essential for coordinated movement patterns
• How do neuromodulators influence central pattern generators (CPGs)?


  • Change output to create different movements
  • Act on voltage-gated channels
  • Modify network behavior for related movements