Motor System 2: Posture and Locomotion Flashcards
What’s the difference between feedforward and feedback motor control?
Feedforward: anticipatory
Feedback: in response to error
What 3 spinal tracts are used for feedforward postural maintenance?
Reticulospinal
Vestibulospinal
Uncrossed corticospinal
What happens if a cat lifts its leg without a feedforward mechanism in place?
It stumbles, relying on feedback to correct for errors.
What is the information for feedback?
Proprioception.
What happens to extensor stretch reflexes after spinal transection? Flexors?
Extensors: Lower amplitude, less coordinated response.
Flexor: they go away completely
Where is the rubrospinal tract in the spinal cord? Is it part of the medial or lateral motor system?
Just anterior to the cross corticospinal tracts. It’s part of the lateral motor system.
Where are the medial and lateral vestibular nuclei?
in the dorsal, lateral-ish medulla
Where are the medial and lateral reticular nuclei?
Medial: pons
lateral: medulla
How do you know that a muscle contraction is anticipatory?
Muscles contract before muscles are actually bearing weight.
What’s a central pattern generator (CPG)? Where is it located?
Network that generates rhythmic movements. It’s located in the spinal cord at the level of the motor neurons that control the relevant limbs.
Is the drive from the brain to walk rhythmic?
No. The walking CPGs convert the signal into rhythmic signals.
How do brain signals for walking, specifically, get to the CPG?
Through the reticulospinal tract.
What happens if you put some spinal cord in a dish and add neurotransmitters that the reticulospinal tract would normally provide?
Rhythmic alternate firing of extensor and flexor motor neurons.
What actually composes the CPG?
Pre-motor interneurons that activate/repress eachother, with one module for flexors, one module for extensors.
Where, within a spinal cord cross section is the CPG located?
In the medial intermediate zone.
