Lec 18 Flashcards
What happens if you cut the spinal cord in a cat then put it on a treadmill.
What would happen if a human tried this.
the cat is still able to walk with because the circuitry that is needed can be controlled by the spinal cord.
Human would have some reflexes like stretch reflex, but could not walk like a cat could
What is the locomotion reflex in the cat due to, what circuit/system
Central pattern generators - neural circuits within the spinal cord can generate rhythmic motor patterns e.g. walking, without input from the brain.
Describe the half centre model (Brown 1911)
What would diagram look like
Two interconnected neural centres
one controls flexor muscles, the other controls extensor muscles.
They alternate to produce movement.
Diagram would have both centres where motor commands could be sent, they would connect to each other via inhibitory interneurons (one going each way). These inhibitory interneurons would connect back to themselves to stop inhibition in preparation for motor command.
What is sensory feedback important for regarding locomotion reflex
explain how each proprioceptor influences this locomotion
- initiate walking (via stretch reflex)
- controlling transitions e.g. from standing to walking
- regulate muscle activity level (spindles prob)
- correct for unexpected disturbances (e.g trip)
- Muscle spindles stretch
- GTO’s detect tension and load
- Joint receptors detect loading on joint
- cutaneous detect pressure on foot
What happen if give rhizotomy to cat
can get some flexion and extension but can’t walk very well, and can’t balance.
proves that afferent info is important to this reflex
Describe “phase-dependant reflex reversal”
Depending on phase of locomotion, e.g. leg on ground vs leg in air, response to obstacle will change.
e.g. stim top of foot during swing = flexion to lift over obstacle and stim on top of foot during stance = extension to get past obstacle.
contrast the crossed-extension reflex with the stumbling corrective response
