lecture 15 - motor system 2 Flashcards
What are some causes of hypotonia?
Motor neuron disease, polio, guillain-barre, cerebellar disease, muscle disease
What are the 3 types/locations of UMN lesions?
cortical, brain stem, spinal cord
What are the effects of a cortical UMN lesion?
UMN motor dysfunction, language/perceptual/cognitive dysfunction
What are the effects of a brain stem UMN lesion?
UMN motor dysfunction, cranial nerve deficits
What are the effects of a spinal cord UMN lesion?
UMN motor dysfunction, sensory pathway disruption
What are the key components of the basal ganglia?
internal capsule, striatum (caudate + putamen), globus pallidus,
What are the motor functions of the basal ganglia?
helps motor cortex select appropriate motor neurons for voluntary movement
What structure in the brain stem inhibits the basal ganglia, and via what neurotransmitter?
The susbtantia nigra, via dopamine
What are some examples of disorders of basal ganglia motor function?
Parkinson’s disease, Huntington’s disease
What is the typical age of onset of Parkinson’s disease?
45-70
What are the 5 key symptoms of Parkinson’s disease?
TRAPS:
Tremor (pill rolling)
Rigidity (lead pipe, cogwheel)
Akinesia/Bradykinesia (no/slow movement)
Postural Instability (forward leaning posture)
Shuffling Gait
What is the difference between a tremor in Parkinson’s vs a tremor from cerebellar dysfunction?
Parkinson’s tremor is present at rest, while in cerebellar dysfunction there is an intention tremor (tremor while trying to execute a function)
What is the rigidity symptom in Parkinson’s disease?
Sustained resistance to passive movements
What is the pathophysiology of Parkinson’s disease?
Death of dopaminonergic neurons in the substantia nigra, which lowers normal feedback to the striatum of the basal ganglia which is needed to contol voluntary movements.
What are the key drugs used in Parkinsons’ treatment?
Levo-dopa, Selegiline, Carbidopa
What is the mechanism of action of L-dopa for Parkinson’s disease?
Is a precursor of dopamine, which crosses the BBB and becomes dopamine, replacing levels lost in Parkinsons
What is Huntington’s Disease?
An autosomal dominant neurodegenerative condition causing progressive death of neurons in the basal ganglia (caudate/putamen)
What is the pattern of inheritance of Huntington’s disease?
Autosomal dominant, worsening with increasing CAG triplets on the Huntingtin gene with successive generations
What are the symptoms of Huntington’s disease?
Chorea (excessive, random movements), dementia, agitiation, mania, paranoia, eventually loss of all voluntary movement
What are the 3 regions of the cerebellum?
Spinocerebellum, cerebrocerebellum, vestibulocerebellum
What does the spinocerebellar tract connect, and what information does it carry?
connects spinal cord with ipsilateral cerebellum, carrying afferent proprioceptive information from the body to assist in movement and posture of the trunks and limbs
What does the cerebro/cortico cerebellar tract connect, and what information does it carry?
connects the cerebral cortex with the cerebellum, carrying efferent information for planning and integrating motor commands
What does the vestibulocerebellar tract connect, and what information does it carry?
Connects the vestibular nerve to the cerebellum. Carries information for balance and eye movement.
What are some of the general signs of cerebellar dysfunction?
Ataxia, hypotonia, intention tremor, gait abnormalities (staggering/lurching), nystagmus/double vision, dysdiadokinesia (inability to perform rapid alternating movements), dysmetria
What are the key functions of the cerebellum?
Planning movements, motor learning
