Locomotion and rhythmic movements Flashcards
How many phases are in a step cycle?
4: F, E1, E2 and E3
What are speed accompanied with in fout limb animals?
Interlimb coordination leading to different gaits
How are the motor patteren of stepping organized?
At the spinal level
What can neuroactive drugs such as serotonine and NMDA added to isolated spinal cord induce?
“Fictive” locomotion
What are central pattern generators (CPGs), and where are they located for locomotion?
Localized networks controlling rhythmic movements
Located in spinal cord
What are the general rules for swimming CPG?
- excitatory CPG interneurons are responsiblefor the rhythm generation
- excitatory neurons are coupled via recurrent excitation and/or electrical coupling
- reciprocal inhibition via glycinergic crossed inhibitory neurons secure left-right alternation and phase muscle activity
- multiple units along the cord
How is it possible to reveal localization of CPGs in mammals?
- ablation/lesion
- optogenetic activation
- demonstrate where active cells are:
1) extracellular/intracellular recordings
2) Ca2+ imaging
What type of neurons form the basis for left-right coordination?
Commissural interneurons (V0)
How does cellular properties contribute to CPG function?
Depending on their ionic channel distribution, and phase transition is regulated by ionic conductances
What brain region initiates locomotion?
Mesencephalic locomotor region (MLR): either CNF or PPN
What does the PPN and CNF control?
PPN: slow explorative locomotion
CNF: fast excape locomotion
What does stimulation of MLR result in?
rhythmic activation in left and right hindlimb extensor soleus muscles
What does tonic stimulation of NRGc result in?
Results in a loss of muscle tone in the extensor muscles
What does stimulation of NRGs during CNF-induced locomotion result in?
Reduced muscle tone and thereby inhibition of locomotion
What does tonic stimulation of NRMc result in?
Produces an increase in muscle tone
