Lecture 50 - Motor Control 1 & 2 Flashcards
what is the hierarchy in motor control
- cerebral cortex
- subcortical nuclei
- brainstem nuclei and cerebellum
- spinal cord
describe the motor neurons in the spinal cord
ventral horn (grey matter)
sensory
cholinergic
summarize the patellar reflex in 5 steps
- tendon tap
- activation of muscle spindles via stretching
- action potential generated
- synapse in the spinal cord - spindle fibers to motor neurons
- motor neuron activation
T/F: most reflexes are monosynaptic
FALSE - involve one or more interneurons
The “withdrawal” reflex utilizes what general circuitry
flexor and cross-extensor reflex arc
what is the righting reflex
animal is flipped onto its back or side, the sensory input from the vestibular system and proprioception triggers motor responses
T/F: the righting reflex is dependent on gravity
TRUE
vestibular nuclei are involved in
modulation of tone in extensor muscles (upright posture)
red nuclei are involved in
unconscious stereotyped movements (gait)
what is in charge if high-order control of gait and control of distal muscles for complex movement
red nucleus
damage to the cerebellum results in what
ataxia
what is the cerebellum in charge of
coordinating motor function and executing rapid movements
T/F: cerebellum receives output from the motor cortex and provides “error” correction signals
TRUE
the Purkinje fibers do what
inhibits unwanted movement
the basal nuclei includes what structures
striatum
globus pallidus external
globus pallidus internal
what does the basal nuclei project to
the thalamus and subthalamic nuclei
what does the basal nuclei receive input from
all cortical areas and the substantial nigra
what input is associated with the substantial nigra
dopamine
summarize the direct pathway in 4 steps
- input from the motor cortex
- synapse GPe to GPi (inhibitory to inhibitory
- sensory input to the motor thalamus
- control unwanted movement
is the substantial nigra excitatory of inhibitory in the direct pathway
excitatory
what is the end goal of the indirect pathway
stop movement
D1 receptors in the ___ pathway facilitate ____
direct; excitation
D2 receptors in the ___ pathway facilitate ____
indirect; inhibition
hypokinesia
inability to initiate movement (Parkinson’s)
hyperkinesia
excessive motor activity (Huntington’s)
what are the functions of the motor cortex
- voluntary control
- proportionately large area devoted to areas of the body w capacity for controlled movements
- corticospinal (pyramidal) tracts
- learned, skilled, fine, voluntary control of muscles
