MODULE 9- Upper Motor Neuron Control of the Brain + Spinal Cord Flashcards
lower motor neurons
the “final common path” for initiating movement
descending systems (upper motor neurons)
-motor cortex
-brainstem centers
motor cortex is responsible for
planning, initiating, + directing voluntary movements
brainstem cortex is responsible for
stereotypical movements, postural control, + gain adjustments
basal ganglia is responsible for
initiation of intended movement + suppression of unwanted movement
cerebellum is responsible for
coordination of ongoing movement
local circuit neurons are responsible for
sensorimotor integration + central pattern generation
motor neuron pools consist of
lower motor neurons
motor + “premotor” areas of the FRONTAL LOBES are important for what
planning + precise control of movement
lateral/ventral corticospinal tract
limb/trunk muscles
corticobulbar tract
facial muscles + tongue
motor control centers in the BRAINSTEM are important for
postural control
motor control centers of frontal lobes (2)
-lateral/ventral corticospinal tract
-corticobulbar tract
motor control centersof brainstem (2)
-lateral + medial vestibulospinal stracts
-reticulospinal tract
upper motor neurons in cerebral cortex to lower motor neurons in medial ventral horn is direct/indirect
indirect
upper motor neurons in cerebral cortex to lower motor neurons in lateral ventral horn are direct/indirect
direct
premotor cortex or primary motor cortex is more anterior
premotor cortex
premotor cortex does movement planning/execution
movement planning
primary motor cortex does movement planning/execution
movement execution
what are the upper motor neurons of the primary motor cortex
pyramidal cells of cortical layer 5
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Betz cells
largest neurons in the human CNS
-accounts for 5% of the corticospinal tract
what accounts for the rest of the upper motor nuerons in the primary motor cortex + premotor cortex
smaller non-Betz cells
are Betz cells the principal upper motor neurons of the motor cortex
NO
-Betz cells are often wrongly assumed to be the principal upper motor neurons of the motor cortex
-pyramidal cells of cortical layer 5 are
despite their small numbers, Betz cells play an important role in what
the activation of lower motor neurons that control muscle activities in the distal extremities
where does the corticobulbar tract terminate
in the brainstem
where does the corticospinal tract terminate
in the spinal cord
how does the lateral branch of the corticospinal tract terminate
decussates (90%)
how does the ventral branch of the corticospinal tract terminate
terminates bilaterally
key areas where facial expressions of emotion are impaired due to damage (e.g., stroke)
-primary motor cortex (middle cerebral artery) of cingulate motor area (anterior cerebral artery)
-contralateral facial motor nucleus (VIII)
-or its nerve
the amount of fine motor control required of the musculature is proportional to what
the amount of motor cortex devoted to it
motor cortex
a map of organized movements
T/F: the motor cortex is a map of individual muscles
FALSE
-it is a map of organized movements
motor maps are created using stimulation applied to the ____
cortical surface
how are muscles used in fine motor control are represented on motor maps
represented by a greater area of the motor cortex
transcranial magnetic stimulation (TMS)
non-invasive stimulation of the human brain
-uses electromagnetic coil + pulsed magnetic field to stimulate cortical region
stopped at slide 12
