Flashcards
N7 - motor control part II
Cards in this deck (44)
- 1role of cerebellumcontrol of muscle tone - keeps you upright
sensorimotor control - adjustments
motor learning - plasticity + LTP
-> sending a learned pattern to different muscles - 2role of basal gangliaintegration of sensory and motor infomation
crucial for intiation of voluntary movement - 3outline the cortex loopcortex - basal ganglia - thalamus - cortex
- 4what two disorders are associated with the basal gangliaParkinsons + Huntingtons disease
- 5what are the 3 functional and anatomical components of the cerebellum1. spino-cerebellum
2. vestibulo-cerebellum
3. cerebro(ponto)-cerebellum - 6what is the function of the spino-cerebellumsensory input from spinal cord
output to the reticular formation + red nucleus + motor cortex
control over axial + postural muscles - 7what happens if spino-cerebellum gets damagedhypotonia (lack of muscle tone)
ataxia (lack of balance/posture)
dysmetria (inaccurate determination of movement - intention tremor - 8what is the function of the vestibulo-cerebelluminput from and output to ventromedial pathway + vestibular nucleus
control over posture + balance + eye movement - 9what happens if vestibulo-cerebellum gets damagedataxia
inability to move eye fast
involuntary eye movements - 10what is the function of cerebro or pontine-cerebellumintracerebral motor loop
instructs primary motor cortex regarding direction of movement, timing + force
compares intended and actual movement - sends compensatory instructions to M1 if they don't match - 11what happens if cerebral-cerebellum is damageduncoordinated antagonistic muscles
poor control of speech
lack of coordination - 12what two cells are in the cerebellumpurkinje and granule cells
- 13what 2 fibres excite purkinje cells?climbing and mossy fibres
- 14what is the output from the purkinje cellsproject to deep cerebellar nuclei
- 15what is hte function of the deep cerebella nucleicompares mossy+climbing afferent inputs before and after cerebellar processing to check if info is matched - if they don't then it sends signal to adjust movement to what it should be
- 16so in summary what are the 4 cerebellar functions1. regulates posture by adjusting output of major descneding motor pathways
2. compares, identifies and corrects discrepencies between intended and actual
3. timer - sequences motor activation
4. motor memroy - learned sequences - 17where is the basal ganglia foundbelow the cortex
- 18what is the basal ganglia always doinginhibiting movement
- 19how does it do thisinhibitory influence from basal ganglia to thalamus - so thalamus is switched off and cant excite the cortex to move
- 20how does this inhibition of the thalamus get removedprefrontal cortex sends excitatory input to basal ganglia which switches off its inhibition and so thalamus is excitated and sends excitatory signal to SMA (supplementary motor area)
- 21what are the 4 main structures in the basal ganglia1. striatum
2. GPi/e (globus pallidus internal+external)
3. STN (subthalamic nucleus)
4. SNr (substantia nigra reticulata) - 22what are the excitatory and inhibitory neurotransmitters in the circuitglutamate
GABA - 23what is the modulatory neurotransmitterdopamine
- 24what are the 2 basal ganglia pathwaysdirect + indirect
- 25describe the direct pathway through basal gangliacortex > striatum > SNr/GPi > thalamus > cortex
- 26describe the indirect pathway through basal gangliacortex > striatum > GPe > STN > SNr/GPi > thalamus > cortex
- 27what does the direct pathway dopromotes movement
- 28name the 2 dopamine receptors and their functionD1 - excitatory
D2 - inhibitory - 29how does dopamine act on the direct pathwaybinds to D1 receptors which excites the striatum > SNr/GPi neurons which inhibits output to thalamus so there is more excitation of thalamus + therefore cortex
causing initiation of movement - 30what does the indirect pathway dosuppresses movement
- 31how does dopamine act in the indirect pathway to activate movementinhibits by binding to D2 receptors
this decreases basal ganglia output so more thalamus activity to cortex - 32what is motor dysfunctionwhen there is inbalance between direct and indirect pathways
- 33give an example of a hypokinetic disorderparkinsons disease
- 34give an example of a hyperkinetic disorderhuntington's disease
- 35what are symptoms of parkinsons diseasetremor
slow movement (bradykinesia)
rigidity - 36what causes parkinsons diseasedopamine loss in basal ganglia
constant excitation of STN
so excessive inhibition of thalamo-cortical pathway (too much basal outflow) - 37treatment for parkinsonsdopamine boosting drugs:
L-DOPA
dopamine agonists
MAO-B inhibitors (inhibiting dopamine breakdown) - 38what else is administered with L-DOPA to prevent production of noradrenalineblocking the enzyme DOPA decarboxylase
this blocker can't enter the brain so dopamine still made in brain but Nadr not made in body - 39what are negatives of L-DOPAeffectiveness diminishes due to progressive nature of disease
so require ever increasing dose - 40name some alternatives to L-DOPAdirectly acting dopamine receptor agonists
e.g. bromocriptine
or
MAO-B inhibitor e.g. selegiline
or
surgical inactivation of STN - 41what causes huntingtons diseasedegeneration of part of the basal ganglia
- 42what is the primary/first pathology of huntingtonsloss of striatal output neurons in indirect pathway which causes decreased basal output so more involuntary movement
- 43what are treatments for huntingtonssymptom relieves:
GABA agonist + DA antagonist (antipsychotic) - 44name two other hyperkinetic disorders of BG origine1. hemiballismus - violent limb flailing due to damage to STN
2. tardive dyskinesia - uncontrolled movement in face + trunk muscles due to incrased dopamine sensitivity
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- Year 2 Biomedicine Year 2 (Neuroscience) Flashcards on N7 - motor control part II, created by Georgie Philpott on 03/01/2023.
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