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Cerebellum and Basal Ganglia
Suzanne Stensaas, PhD(David Roman Renner, MD)
2009 Kenya Curriculumrepurposed for Dental Neuroanatomy
2012
BG
CBLM
BASALGANGLIA
consultant onautomaticmovements
providesinput into thethalamus
Courtesy of Stephen C. Voron, MD
T
Courtesy of Stephen C. Voron, MD
Cerebellum:
consultant onrapidmovements
providesinput into thethalamus
BG
CBLM
Basal Ganglia Symptoms
• resting tremor• postural instability• festination• rigidity• masked facies• bradykinesia• dyskinesia• torticollis• chorea• athetosis• hemiballismus• akathisia
Cerebellar Symptoms
• intention tremor• dysmetria• dysdiadochokinesia• hypotonia• heal to shin• finger to nose• rebound• ataxic gait• titubation• nystagmus• dysmetric saccades
Most movement disorders produced bycerebellar and basal ganglia pathologydisappear during sleep.
Cerebellar and basal ganglia signs areusually not present if the corticospinal tractis damaged.
The cerebellum is the great comparator:
1. It compares cortical willful command with muscle tension, joint position, & tone (via ipsilateral spinocerebellar tracts)
2. Advises the cortex on how much, how many, how fast3. The motor cortex sends the revised command down the corticospinal tract
The BASAL GANGLIA are the autopilotfor procedural movements.
The CEREBELLUM is the refiner offinely controlled movements
(particularly of fingers).
COMPARISON OF MOTOR SYSTEMShttp://library.med.utah.edu/neurologicexam/html/home_exam.html
Lower Motor Neuron
Spinal Cord
Upper Motor Neuron
Corticospinal Tract
Cerebellum Basal Ganglia
Normal
Efferent part of
monosynaptic reflex
Voluntary movement Rapid coordinated alternating
skilled movements that are
learned
Facilitates intentional
movements and inhibit
extraneous movements
Muscle tone by
inhibiting antagonists
Muscle tone Eye-head movements Autopilot for motor activities
Maintains muscle
fibers (trophic factors)
Fine control, espec. finger
flexors
Posture and Gait
Inhibitory to Lower motor
neurons
Balance, equilibrium,
orientation in space
Voluntary movements in an
automatic manor.
Weakness or paralysis Weakness or paralysis timing, duration, and amplitude
Abnormal
Areflexia Hyperreflexia
Hyperactive deep tendon
reflexes
Truncal ataxia, gait ataxi a Shuffling or festinating gait,
small steps, hard to turn
Fasciculation Babinski- extensor plantar
reflex
Nystagmus, Dizziness , Masked facies, few blinks
Muscle Atrophy Spasticity Decomposition of movement Difficulty turning or starting,
hypokinetic = bradykinesia
Flaccid paralysis Dysmetria- ataxia of arms Paucity of associated
movements
Dysynergia
Dysdiadochokinesia- inability
to do rapid alternating
movements
Chorea, athetosis,
hyperkinetic
Hypotonia- pendular reflexes Rigidity ( lead-pipe )
(cogwheel),
Intention tremor Resting tremor
Scanning speech Soft speech