Lecture 8 Motor 2 Flashcards
what are the functions of the primary motor cortex?
signals motor neurons to contract skeletal muscle fibers
signals via the corticospinal tract
execution done by cerbellum and basal nuclei
What makes up the cerebral cortex?
Primary motor cortex 4
Premotor cortex 6
Supplementary cortex 6
what is the function of the premotor cortex?
plan movements based on sensory and visual cues
what is the function of the supplementary motor area
retrieves and coordinates memorized motor sequences
what are the motor cortex functions?
activating signals to spinal cord
issues sequential and parallel commands
cortical patters are usually complex, can be learned
patterns are hereditary and hard wired
what does the cerebellum play a major role in?
timing of motor activities and in rapid, smooth progression from one muscle movement to the next
list some features of the cerebellum
learns from mistakes
not essential for locomotion
compares actual and intended movements
works with spinal cord to enhance stretch reflex
works with brain stem to make postural movements
what does the basal nuclei do?
plans and controls complex patterns of muscle movement, controlling relative intensities of the separate movements, directions and sequencing
helps plan parallel seq patterns
what happens if cerebellum is removed?
body movements become highly abnormal
what are the 2 hemispheres separated by?
what are they divided into?
vermis
intermediate and lateral zones
what are the 3 lobes?
anterior
posterior
flocculonodular
what is the vermis the location for?
muscle movements of axial body, neck, shoulders, hips
what is the intermediate zone location of?
muscle contractions of the distal upper and lower limbs, hands, feet, fingers, toes
what is the lateral zone location for?
with the cerebral cortex with planning of sequential motor movements
what does the cortex consist of?
transversely arranged narrow gyri called folia
what are the types intracerebellar nuclei?
Dentate
Emboliform
Globose
Fastigial
DEG lesions lead to what?
where do these project to?
related to what?
extremity ataxia
red nucleus
limb musculature and fine movements
Fastigial lesions lead to what?
fibers project to where?
related to what?
trunk ataxia
reticular formation and vestibular nuclei
postural activity and limb movements via reticulospinal and vestibulospinal tracts
what are granular cells?
inhibitory or excitatory?
axons from parallel fibers in cortex
excitatory
what are golgi cells?
EX or INHIB
project from parallel fibers to granular cell bodies
inhibitory
what are basket cells?
ex or in
project from parallel fibers to purkinje axon hillock
Inhibitory
what are stellate cells?
ex or in
project from parallel fibers to Purkinje dendrites
Inhibitory
What are 4 features of Purkinje cells?
have extensive dendrite branching
receive input from parallel fibers
project to intracerebellar nuclei (-)
ONLY output from cortex
where is each functional unit centered?
on a Purkinje cell and corr. deep nuclear cell
what is the output from a functional unit from?
deep nuclear cell
where do climbing fibers originate from?
inferior olives
where do mossy fibers send signals to?
excitatory collateral to deep nuclear cells and then synapse in granular layer with thousands of granule cells
Direct stimulation by climbing and mossy fibers does what?
excites deep nuclear cells
what inhibits deep nuclear cells?
Purkinje cell signals
what are the 3 levels of nervous system control involving the cerebellum to coordinate motor function?
vestibulocerbellum
spinocerebellum
cerebrocerebellum