Voluntary movements Flashcards
What are semi-automatic actions
‘voluntary’ but you dont have to think about them (often repeated movement_
EX. walking, breathing, chewing
What are CPGs
Central pattern generators
Specific to the action they initiate/maintain
What control CPGs
-Higher control neurons
-feedback loops from effector organs responding to the environment
-sensory feedback loops
What are voluntary actions
Self initiated
Purposeful
Learned
Improved with practice
Adaptible
How do we elicit voluntary movement
Motor cortex
How many neurons do motor pathways incorporate
2
What are the two motor pathways
Corticospinal
Corticobulbar
Where do motor neurons pass through in the spinal chord
Dorso-lateral funiculus
Ventromedial funiculuc
What is the breakdown of the corticobulbar pathway
Signal passes from cortex to the basis pendunculi in the midbrain down the spinal chord where it branches to innervate the:
Trigeminal nerve
Facial nerve
Vagus nerve
Hypoglossal nerve
Where does the motor neuron pass through in the Pons, and medulla as it descends the brain in the corticobulbar pathway
Trigeminal motor nucleus
Facial motor nucleus
Nucleus ambiguus
How can we carry out bilateral movements
Descending projections bifurcate and innervate motor neurones on both sides of neuro axis
What pathways involves innervation of neurons within the spinal chord
Corticospinal pathway
How many corticospinal projections from one motor hemisphere will cross to the contra-lateral side at the pyramidal decussation
85%
How many projections remain on the anterior corticospinal pathway
15%
Where does the lateral corticospinal tract lie
within the dorso-lateral funiculus
What is found within the ventro-medial funiculus
Anterior corticospinal tract
When does the anterior corticospinal tract end
Mid-thoracic level
Where do pathways to motor neurons controlling distal muscles (hands,feet) originate
The opposite side of the brain
Where receives bilateral descending cortical commands
Upper face (gag reflex)
What happens if the upper or lower motor neurons are damaged
loss of ability to initiate movement
What conditions lead to temporary paralisis
Bell’s palsy - affects the facial nerve
How do we refine our motor output to respond to the environment and process information while moving
Inputs from the thalamus and basal ganglia which can influence activity of upper motor neurons directly
What sections of the brain can modify motor output
Thalamus, basal ganglia, cerebellum, brainstem
What are the basal ganglia
Influence/regulate output from the motor cortex
Act to initiate actions and to switch from one action to another
Link to the cerebral cortex via feedback loops
