Indirect Motor Pathway Flashcards
Description of indirect
Polysynaptic not mono
Has many pathways
Indirectly influence spinal nerve- many synapse not just one
Another name for indirect motor pathway
Extra pyramidal tract
Indirect function to coordinate and adjust
Posture and balance
Indirect function to coordinate and regulate/edit
Rate, force, timing of movements
Indirect function regulate and inhibit
Reflexive movements
Direct vs indirect in purpose
Direct- move this way or that way
Indirect- edit and regulate movement
Methods indirect- relies upon
And works with basal ganglia and cerebellum
Methods indirect- works simultaneously
With pyramidal pathways-direct shoot down to alpha motor neuron
Method indirect modifies messages
Generated by primary motor cortex
Method indirect pathway
Complicated, round-about, many of them
Method indirect: amount of synapses
Polysynaptic (has many synapses l, not just one, as direct has)
Indirect method: does not provide direct input to LMNs
Jus edit and fixes
Gets it to interneuron which synapses with LMN
Why called extrapyramidal
Because functions ‘outside’ of the system if tracts moving through the pyramidal structure of the medulla in the brainstem
Indirect structures
Basal ganglia
Brainstem (midbrain)
Cerebellum
Indirect basal ganglia
Globus pallidus Putamen Caudate nucleus -substantia nigra -sub thalamic nucleus
Indirect brainstem
Red nucleus- iron cells
Reticular formation
3 parts of the brainstem
Midbrain
Pons
Medulla
Cerebral peduncle all converge at internal capsule
Projection fibers efferent and afferent
Pons
3 cerebellar peduncles attach here- roots of cranial nerves emerge here
What synapses at pons
3 corticobulbar synapse here with cranial nerves
Indirect motor system throughout
Almost entire brainstem- same structures as direct
Basal ganglia and cerebellum, reticular formation
Brainstem structures involved in indirect motor pathways
Reticular formation and red nucleus
What us reticular formation
Collection of cells scattered amongst some cranial nerve nuclei and some fiber tracts within the brainstem
Reticular formation course
Vertical
Long extension of these cells throughout midbrain, pons, and medulla
What does reticular formation do
Mediates basic levels of consciousness arousal and attention (not in coma)
Major player in mediating messages sent to LMNs
Red nucleus description
Cluster if cells in the midbrain
Red nucleus receive input from
Motor cortex and BG, and feedback from cerebellum
Red nucleus Further modifies
Motor messages on their way down
Substantia nigra technically located
Within the brainstem (midbrain)
Substantia nigra functionally apart of
Basal ganglia
Substantia nigra does what
Info to and from the BG
Critical producer of dopamine
Subthalamic nucleus technically part of
Thalamic nuclei
Sub thalamic nucleus functionally part of
Basal ganglia
Sub thalamic nucleus does what
Receives input from globus pallidus, motor cortex
Head right back up to globus pallidus
Direct versus indirect
Direct- initiate, decussate, one synapse
Indirect- regulate, some decussate or don’t
Indirect job
Editorial work: inhibit unnecessary amounts of muscle tone
Spasticity
Too much tone
Indirect motor pathways concepts some
Some decussate
Some remain ipsilateral, some do both
Indirect motor pathways all concept
Provide indirect influence upon LMNs by synapse at interneuron
Engage in my multi-synaptic circuitry
Final synapses with inter-neurons to indirectly influence the movement executed by the LMN
Cranial nerves damage
Speech, swallowing
