Assistant Professor Department of Neurobiology and Anatomy University of Texas Health Science Center at Houston Houston TX MichaelSBeauchamputhtmcedu Motor Systems Lecture 5 Hierarchical ID: 321124
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Michael S. Beauchamp, Ph.D.Assistant ProfessorDepartment of Neurobiology and AnatomyUniversity of Texas Health Science Center at HoustonHouston, TX
Michael.S.Beauchamp@uth.tmc.edu
Motor Systems: Lecture 5Slide2
Hierarchical Organization Of Motor StructuresLevel 4: Association CortexLevel 2: Brain Stem (Red Nucleus, Reticular Formation, Vestibular Nuclei, Tectum, Pontine Nuclei, Inferior Olive)Level 1: Spinal CordLevel 3: Motor Cortex
Side Loop 1:
Basal Ganglia
(Caudate Nucleus,
Putamen
,
Globus
Pallidus
,
Substantia
Nigra
,
Subthalamic
Nucleus)
Thalamus
(VA,VL,CM)
Side Loop 2: CerebellumSlide3
Cerebellar Functions10% of brain volume, > 50% of brain’s neuronsThe coordination of movementMaintenance of balance and postureCoordinated execution of voluntary movementsMotor learningCognitive functionsSlide4Slide5Slide6
Gross Anatomical Organization of CerebellumSlide7
DentateFastigialInterposed
Deep Cerebellar Nuclei
AlsoLateralVestibularSlide8
Cerebellar Afferents and EfferentsSlide9
Deep Cerebellar NucleiFastigial Nucleus inhibitory input from cerebellar cortex: vermis excitatory input: vestibular, proximal somatosensory, auditory, visual projects to vestibular nuclei, reticular formationSlide10
Cerebellar Afferents and EfferentsSlide11
Deep Cerebellar NucleiFastigial Nucleus inhibitory input from cerebellar cortex : vermis excitatory input: vestibular, proximal somatosensory, auditory, visual projects to vestibular nuclei, reticular formationInterposed inhibitory input from cerebellar cortex : intermediate zone
excitatory input : spinal, proximal somatosensory, auditory, visual projects to
contralateral red nucleusSlide12
Cerebellar Afferents and EfferentsSlide13
Deep Cerebellar NucleiFastigial Nucleus inhibitory input from cerebellar cortex : vermis excitatory input: vestibular, proximal somatosensory, auditory, visual projects to vestibular nuclei, reticular formationInterposed inhibitory input from cerebellar cortex : intermediate zone
excitatory input : spinal, proximal somatosensory, auditory, visual projects to
contralateral red nucleusDentate inhibitory input from cerebellar cortex
: lateral hemisphere
excitatory input: cortex via
pontine
nuclei
projects to
contralateral red nucleus, thalamus (VL)
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DeArmond Fig. 81Slide15
Cerebellar Afferents and EfferentsSlide16
Deep Cerebellar NucleiFastigial Nucleus inhibitory input from cerebellar cortex : vermis excitatory input: vestibular, proximal somatosensory, auditory, visual projects to vestibular nuclei, reticular formationInterposed inhibitory input from cerebellar cortex : intermediate zone
excitatory input : spinal, proximal somatosensory, auditory, visual projects to
contralateral red nucleusDentate inhibitory input from cerebellar cortex
: lateral hemisphere
excitatory input: cortex via
pontine
nuclei
projects to
contralateral red nucleus, thalamus (VL)
Vestibular
inhibitory input from
cerebellar
cortex
:
flocculonodular
lobe
excitatory input: vestibular labyrinth
projects to
motor nucleiSlide17
Cerebellar Afferents and EfferentsSlide18
Cerebellar PedunclesInput and output tracts of cerebellumInferior Cerebellar Peduncle (restiform body) Primarily afferent fibers from medullaMiddle Cerebellar Peduncle (brachium pontis) Primarily afferent fibers from ponsSuperior
Cerebellar Peduncle (brachium conjunctivum
) Primarily efferent fibers from the cerebellar nucleiCerebellum controls the IPSILATERAL side of the bodySlide19
Functional Divisions of CerebellumVestibulocerebellum flocculonodular lobe lateral vestibular nuclei oldest part of cerebellum postural and vestibular reflexesSpinocerebellum vermis and intermediate zone fastigial and interposed nuclei motor coordinationCerebrocerebellum lateral hemispheres dentate nuclei planning and timing of movementsSlide20
Cerebellar Afferents and EfferentsSlide21
Internal Circuitry of CerebellumSlide22Slide23Slide24
Cerebellum Produces Movement DisordersSlide25
Cerebellum and Motor Learning Vestibulo-ocular reflex Coordination of movements Pavlovian Classical ConditioningSlide26
The Cerebellum and Motor LearningSlide27Slide28Slide29
Cerebellum and Motor Learning Vestibulo-ocular reflex Coordination of movements Pavlovian Classical ConditioningSlide30Slide31
Cerebellum as a Control SystemFeedback Controller for Slow movements (e.g., posture)Feedforward Controller for Fast movements (e.g., most voluntary movements) Slide32
Feedback control systemDESIREDOUTPUTSENSOREFFECTOR
OUTPUT
Error signal
Feedback signal
COMPARATOR
+
–Slide33Slide34
DESIRED OUTPUT
FEED-FORWARD CONTROLLER
SENSOR
EFFECTOR
ADVANCE
INFORMATION
OUTPUT
Feed-forward
control signal
Feedforward control systemSlide35
MOTOR CORTEX
CEREBELLUM
SENSOR
EFFECTOR
ADVANCE
INFORMATION
OUTPUT
Feed-forward
control signal
Cerebellum as a feedforward control system
Mossy Fibers
Climbing Fibers (Error signal)
Mossy FibersSlide36
Internal Circuitry of Cerebellumdesired outputadvance sensory informationerror signalSlide37
VOR and feedforward controlvestibular informationabout head movementretinal slipSlide38Slide39
Cerebellum plays a crucial role in motor coordination by acting as a feedforward controller, allowing the organism to learn through trial and error what exact pattern and sequence of motor commands is necessary to produce rapid, accurate, and effortless movements Cerebellum as feed forward controller