MOTOR%20SYSTEMS:%20THE%20CEREBELLUM%20AND%20BASAL%20GANGLIA

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MOTOR SYSTEMS THE CEREBELLUM AND BASAL GANGLIA

• D. C. MIKULECKY
• PROFESSOR OF PHYSIOLOGY
• AND
• FACULTY MENTORING PROGRAM

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THE CEREBELLUM AND BASAL GANGLIA COORDINATE
MOVEMENTS

• THE CEREBELLUM IS INVOLVED IN PLANNING,
  COORDINATION, AND POSTURE
• ANTERIOR AND POSTERIOR LOBES INVOLVED IN LIMB
  MOVEMENT
• FLOCCULONODULAR LOBE IS INVOLVED IN EQUILIBRIUM
  AND POSTURE

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ANATOMY OF THE CEREBELLUM
Lateral Zone
Intermediate Zone
Floculonodular Lobe
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SOMATIC SENSORY PROJECTIONS ONTO THE CEREBELLAR
CORTEX
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FUNCTIONS OF THE CEREBELLUM

• PLANNING OF A MOVEMENT
• CONTROL OF POSTURE AND EQUILIBRIUM
• CONTROL OF SMOOTH LIMB MOVEMENT

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CELL TYPES AND CIRCUITS IN THE CEREBELLUM
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PURKINJE CELLS ARE THE MOST PROMINENT OF ALL THE
CEREBELLAR CELL TYPES

• TWO INPUTS CLIMBING FIBERS (FROM OLIVARY
  NUCLEUS) AND PARALLEL FIBERS FROM GRANULE CELLS
• OUTPUT VARIES ACORDING TO INPUT CLIMING FIBERS
  LEAD TO COMPLEX PATTERNS WHILE PARALLEL FIBERS
  GENERATE SIMPLE PATTERNS

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THE BASAL GANGLIA
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THE BASAL GANGLIA PLAN MOVEMENTS

• PRIMARY INPUT FROM NEOCORTEX
• OTHER INPUTS FROM THE THALAMUS AND SUBSTANTIA
  NIGRA
• GLOBUS PALLIDUS PROVIDES OUTPUT
• COGNITIVE FUNCTIONS

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BASAL GANGLIA AFFERENT CONNECTIONS
CORTEX
CAUDATE
THALAMUS
PUTAMEN
SUBSTANTIA NIGRA
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BASAL GANGLIA INTRINSIC CONNECTIONS
CORTEX
CAUDATE
THALAMUS
PUTAMEN
GLOBUS PALLIDUS
SUBSTANTIA NIGRA
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BASAL GANGLIA EFFERENT CONNECTIONS
CAUDATE
THALAMUS
PUTAMEN
GLOBUS PALLIDUS
SUBSTANTIA NIGRA
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BASAL GANGLIA OUTPUT TO CORTEX VIA THALAMUS

• MODULATE DESCENDING COMPONENTS OF THE MOTOR
  SYSTEM
• ADDITIONAL OUTPUTS TO SUBSTANTIA NIGRA USE
  DOPAMINE AS NEUROTRANSMITTER THESE DEGENERATE
  IN PARKINSONS DISEASE

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THE VESTIBULAR APPARATUS

• SEMICIRCULAR CANALS HAIR CELLS SENSE MOTION
• THREE COORDINATE PLANES SUPERIOR, INFERIOR, AND
  HORIZONTAL
• UTRICLE AND SACCULE DETECT LINEAR ACCELERATION IN
  HORIZONTAL AND VERTICLE PLANES

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THE VESTIBULAR APPARATUS UTRICLE SACCULUS
ONE CANAL IN EACH COORDINATE PLANE
UTRICLE SACCULUS
AMPULLA
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THE UTRICLE SACCULUS
OTOCONIA (CALCIUM CARBONATE CRYSTALS)
OTOLITHIC MEMBRANE- GELATINOUS LAYER
HAIR CELLS
NERVE CELLS
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THE UTRICLE SACCULUS
HEAD MOVEMENT
OTOCONIA (CALCIUM CARBONATE CRYSTALS)
OTOLITHIC MEMBRANE- GELATINOUS LAYER
HAIR CELLS
NERVE CELLS
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THE VESTIBULAR APPARATUS SEMICIRCULAR CANALS
ONE CANAL IN EACH COORDINATE PLANE
UTRICLE SACCULUS
AMPULLA
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THE AMPULLA
HAIR CELLS
NERVE CELLS
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THE AMPULLA
MOVEMENT OF HEAD
INERTIAL FLUID MOVEMENT
HAIR CELLS BENT
NERVE CELLS FIRE
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DISEASES OF THE MOTOR SYSTEM

• UPPER-MOTOR-NEURON LESIONS
• CORTICOSPINAL TRACT LESIONS
• LOWER MOTOR NEURON LESIONS
• CEREBELLAR LESIONS

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UPPER-MOTOR-NEURON LESIONS

• PARALYSIS ON SIDE OF BODY OPPOSITE LESION
• INCREASED MUSCLE TONE
• EXTENSION OF BIG TOE AND BABINSKI SIGN
• LACK OF MUSCLE ATROPHY

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CORTICOSPINAL TRACT LESIONS

• LOSS OF STRENGTH AND MOVEMENT OF MUSCLE GROUPS
• LOSS OF STRENGTH IN VOLUNTARY MUSCLE CONTRACTION
• BABINSKI SIGN

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LOWER MOTOR NEURON LESIONS

• IPSOLATERAL HYPOACTIVE REFLEXES
• PARALYSIS
• FLACID MUSCLES WITH PROMINENT ATROPHY

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CEREBELLAR LESIONS

• IPSILATERAL DISTURBANCES
• LATERAL LESIONS RESULT IN COORDINATION LOSS
• LESIONS IN THE VERMIS PRODUCE ATAXIA (LOSS OF
  COORDINATION)
• FLOCCULONODULAR LOBE LESIONS PRODUCE EQUILIBRIUM
  DISTURBANCE AND ATAXIA