block 5 lecture 14 basal ganglia and cerebellar Flashcards
briefly what does the cerebellum do?
coordinates ongoing movement, balance, muscle tone
briefly what does the basal ganglia do?
selects and initialtes voluntary movement
briefly what does the cerebral cortex do?
initiate movement
how do the basal ganglia and cerebellum improve accuracy?
feedback loops using motor and sensory systems
what presents if there is damage to the cerebellum?
jerky movement, uncoordinated, inacurate, ataxia
what presents if there is damage to the basal ganglia?
uncontrolled movement at rest
what is the motor circuits involving upper motor neurons?
cerebral cortex to the brainstem/spinal cord
what are the two motor circuits of the lower motor neurons?
brain stem to the head muscles and then movement
spinal cord to the body muscles and then movement
what are the fold of the cerebellum called?
folia
where is the vermis in the cerebellum?
middle
where is grey and white matter in the cerebellum?
white matter is in the middle and grey matter is on the outside
what are the functions of the cerebellum?
comparer function and motor memory
what is the comparer function of the cerebellum?
detects difference in motor function, there is a difference between actual ad intended movement, correction of ongoing movement
what is the motor memory function of the cerebellum?
stores learned movement, changes from conscious to unconscious,
what are the three main divisions of the cerebellum?
cerebrocerebellum
spinocerebellum
vestibulocerebellum
where does the cerebrocerebellum receive inputs?
cerebral cortex
what does the cerebrocerebellum do?
regulation of highly skilled movements
where does the spinocerebellum receive inputs?
direct input from the spinal cord
what does the spinocerebellum do?
laterally: movement of the distal muscles
centrally: movement of the proximal muscles
what is the vestibulocerebellum made up of?
nodulus and flocculus
where does the vestibulocerebellum receive inputs from?
vestibular nucei and brainstem
what does the vestibulocerebellum do?
movements for posture and balance
what is the cerebellum attatched to the brainstem by?
peduncles
what are the superior cerebellar peducles?
efferent pathways from the cerebellum - motor commands
what are the middle cerebellar peducles?
afferent pathways - sensory info
what are the inferior cerebellar peducles?
afferent and efferent pathways
where are the main inputs to the cerebellum form?
frontal and parietal cortex
how do the frontal and parietal cortex inputs enter the cerebellum?
pontine nuclei
what part of the cerebellum do commands from one side of the brain supply in the cerebellum?
opposide due to crossing the midline
where do information about proprioception, vestibular system, visual and auditory come from for the cerebellum?
spinal cord and vestibular nuclei
how does the proprioception, vestibular system, visual and auditory information enter?
ipsilaterally
what does the inferior olive nuceli provide the cerebellum?
information about timing, learning and memory
where do all the inputs to there cerebellum enter through?
inferior cerebellar peduncle
from the deep cerebellar nuclei where are the neurons sent?
thalamus
what do the neurons from the cerebellum synapse with in the thalamus?
primary motor cortex and the premotor cortex
where does the vestibulocerebellum relay information to?
fastigial nuclei
where does the spinocerebellum relay information to?
interposal nuclei
where does the cerebrocerebellum relay information to?
dentate nuclei
where do the inputs of the cerebellum come through?
climbing fibers which originate in the inferior olive
mossy fibers
what are the outputs of the cerebellum sent via?
purkinje fibers
what is a feature of the purkinje fibers?
highly branched
what are interneurons?
granule/satellite/golgi and basket cells
what is the outer layer of the cerebellum?
outer layer: molecular layer
what is the middle layer of the cerebellum?
purkinje
what is the inner layer of the cerebellum?
granule cell layer
what cell contains most of the input to the cerebellum?
mossy fibers
what do the mossy fibers synapse with?
granule cells
what do the granule cells do?
send an axon which goes to the molecular layer and for fibers that are parallel with the surface of the cerebellar cortex
what do the granule cells synapse with?
dendrites of the purkinje cells
where do the purkinje cells receive input from
granule cells and climbing fibers
where do the climbing fibers originate from?
inferior olive
what do the climbing fibers carry?
error signals
what do granule cells receive input from?
climbing fibers
what is the granule cell output
T shaped parallel fiber
what do the purkinje cells synapse with?
neurons deep in the cerebellar nuclei
what do the purkinje fibers use at the synapse?
inhibitory neurotransmitter - GABA
what is GABA?
inhibitory neurotransmitter
how are the climbing fibers structured in relation to the purkinje fibers?
twist around the dendrites
with cerebellar damage where are the movement errors?
on the same side
what is the vestibulocerebellum responsible for?
balance and eye movements
what is the spinocerebellum responsible for?
impaired gait
what is the cerebroocerebellum responsible for?
highly skilled movements
what is dysnergia?
loss of synergistic multi joint movement
what is dysmetria?
inability to judge distance
what is dydiodochokinesia?
cant do rapid alternating movements
what is intentional tremmor?
tremmor when trying to move
what is ataxic dysarthria?
slurred speech
what can heavy drinking damage?
anterior cerebellum
what does damage to the anterior cerebellum do?
affects movement of the lower limbs
why cant you tickle yourself?
somatosensory cortex receives signals from the cerebellum to supress the sensation
what are the series of nuclei of the basal ganglia?
caudate, putamne, globus, substantia niagra/ sub-thalamic
what is the caudate and putamen input zone called?
striatum
what is the input zone of the globus pallidus and the substantia nigra?
pars reticula
what are the motor functions of the basal ganglia?
exerts an inhibitory influence to modulate initiation or termination of motor commands from the motor cortex
selects and maintains voluntary movement
can suppress inappropriate movements
what are the non motor functions of the basal ganglia?
cognition, working memory and attention
where do the main input to the basal ganglia come in to?
striatum
what is the excitatory neurotransmitter used in the striatum?
glutamate
where does information come from and go to in the corticostriatum pathway?
from the cortex: fronatl and parietal lobes
to the striatum
where does information come from and go to in the nigrostiatal pathway?
substantia nigra pars compacta to the striatum
neeurotransmitter in the nigrostiatal pathway?
dopamine
what are the medium spiny neurons?
neurons in the striatum that receive input
what is the output pathway from the striatum for eye movements?
striatum to substantia nigra pars reticular to superior colliculus
what is the output pathway from the striatum for limb and truck movements?
striatum to globus pallidus internal to thalamus to frontal cortex
what does the direct pathway do?
accelerator of movement, removes inhibition of the thalamus
what does the indirect pathway do?
inhibitor effect
what are the neurotransmitter of the indirect and direct pathways?
dopamine
what is the receptor in the direct pathway?
D1
what is the receptor in the indirect pathway?
D2
what happens in the direct pathway?
globus pallidus tonically inhibits thalamus during the excitation of the motor cortex
what is parkinsons caused by?
hereditory or damage
what does hypokinesia disorder mean?
paucity of movement
what are the clinical characteristics of parkinsons?
T tremor
R ridgidity of movement
A akinsthia
P postural problems
what happens to the pathways in parkinsons?
direct pathway is decreased and the indirect pathway is increased
what happens in parkinsons?
death of the cells of the substantia nigra which reduces dopaminergic effects of D1 and D2 receptors
what are the treatments of parkinsosn?
L-DOPA dopamine agonists foetal cell transplants deep brain stimulation pallidotomy thalatomy
what does LDOPA do in parkinsons?
precurser of dopamine, boosts dopamine levels in the substantia nigra neurons
what do dopamine agonists do in parkinsons?
stimulate postsynaptic dopamine receptors in the striatum
what happen in foetal cell transplant in parkinsons?
foetal mesencephalic cells are put in the putamen
what is huntingtons?
genetic disease on chromosome 4
what happens in huntingtons?
loss of output neurons of striatum, cortical motor cortex is over activated
what is the treatment of huntingtons?
tetrabenzine
what does tetrabenzine do for huntintons treatment?
depletes dopamine
what is heminbalismus?
flinging movement of the limbs on one side of the body due to damage to subthalamic nucleus
what is the treatment in huntingtons?
depleting dopamine levels
