Basal Ganglia and Cerebellum Flashcards
What does Direct Pathway do?
Facilitates target-oriented movement
What does the Indirect Pathway do?
Inhibits competing/unwanted movements
Which Dopamine receptors are associated with Direct/Indirect Pathways?
Direct: D1
Indirect:D2
Which parts of the thalamus does Globus Pallidus internus communicate with?
VA or VL
What NT does Globus pallidus internus release?
GABA
What NT does Globus Pallidus externus release?
GABA
What NT does the STN release?
Glutamate
What NT does the thalamus release to the cerebral cortex?
glutamate
Describe the Direct Pathway
Cortex/ SN–> Putamen/Caudate (striatum) (D1 receptors)–> GPi–> VA or VL of Thalamus–> Cortex
Describe the Indirect Pathway
Cortex/SN–> Putamen/Caudate (D2 receptors)–> GPe–> STN–> GPi–> VL or VA of Thalamus–> Cortex
The Caudate, Putamen, and Nucleus Accumbens together form the____________
Striatum
Together, the Putamen and Globus Pallidus for the ______________
Lentiform Nucleus
Branches of which artery supply the Basal Ganglia?
MCA (lenticulostriate branches)
Which part of the brain is selectively destroyed in Huntington’s?
striatum
Which part of the brain is damages in Hemibalismus?
STN
Name 2 therapies for Parkinson’s
L-DOPA, Deep Brain Stimulation, Pallidotomy,
BONUS: Which part of the brain does the Caudate associate with?
frontal cortex (organization of behavior and personality)
BONUS: Which part of the brain does the Putamen associate with?
cortical motor areas
BONUS: which part of the brain does the Nuc. Accumbens associate with?
cingulate gyrus (affect and motivation)
What are the functions on the flocculonodular lobe of the cerebellum?
eye movements, head position in space, balance
What is the function of the vermis of the cerebellum?
truncal coordination/posture
What is the function of the intermediate hemispheres of the cerebellum?
limb coordination, gait
What is the function of the lateral hemispheres of the cerebellum?
planning, cognitive functions, motor learning
What do the 3 cerebellar peduncles connect to?
Superior: Midbrain
Middle: Pons
Inferior: medulla
Which cerebellar peduncle(s) mainly carry incoming afferent information?
Middle and Inferior
Which cerebellar peduncle(s) carry OUTput information from the cerebellum?
Which parts of the brain does this output info go? (2)
Superior peduncle
Red Nucleus (midbrain) and VL of Thalamus
What is the primary nucleus in the cerebellar deep nuclei?
Dentate Nucelus
Where is the information going through the Middle Peduncle coming from? (Ipsilateral or Contralateral?)
CONTRALATERAL (info crosses IN Sup. Cerebellar puduncle) cortex via Basis Pontis–> corticopontine tracts mostly from supplementary motor cortex
Name the 4 deep cerebellar nuclei from medial to lateral
Fastigial–> Globose–> Emboliform–> Dentate
“Fat Guys Eat Donuts”
What do you expect to find on physical exam with CEREBELLAR dysfunction? (8)
1) dysmetria
2) dysdiadokinesis
3) scanning speech
4) NEGATIVE Romberg sign
4) nystagmus
5) truncal ataxia
6) “Wide-based” gait
7) tremor (Intention tremor)
8) lack of coordination
Define: Clasp-knife rigidity, Cogwheel rigidity, and Leadpipe rigidity
Clasp-Knife: increased tone followed by sudden loss of rigidity at end of external flexion (UMN damage)
Cogwheel: catch and release (Parkinson’s)
Leadpipe: increased tone throughout passive movement
Cerebellar dysfunction results in Contralateral or Ipsilateral deficits?
Why?
Ipsipateral
Inputs into the Inferior Peduncle come from IPSILATERAL dorsal spinal cerebellar tracts and inferior olive.
Where is the information going through the Inferior Peduncle coming from? (Ipsilateral or Contralateral information)
Inputs from IPSILATERAL dorsal spinocerebellar tract (proprioception from muscle spindles) and inferior olive, vestibular nuclei and eye muscles
Which arteries supply the cerebellum?
SCA, PICA, AICA
How many cellular layers are in the cerebellar cortex? What are they?
3- Molecular, Purkinje, and Granular
Describe the major pathway of the cerebellum (starting with Climbing Fibers)
Climbing fibers from inferior olive–> Purkinje cells–> inhibit deep cerebellar nuclei (Dentate)–> Red Nuc. and VL of thalamus–> Primary motor cortex–> pons–> contralateral cerebellar cortex (Mossy fibers)
Can damage to cerebellar inputs look like cerebellar lesion?
YES!
What can happen cerebellum expands?
Upward herniation–> CSF outflow obstruction, sleepiness, or midbrain syndrome (upward gaze)
Anterior dislocation–> CSF outflow obstruction
Downward herniation–> compress essential medullary structures
Define: Akathisia
motor restlessness
Define: Athetosis
slow, writhing movements
Define: Ballism
Proximal, large-amplitude chorea. Typically unilateral.
Define: Chorea
Non-rhythmic, unpredictable movements. Involuntary, randomly flowing jerks of muscles
Define: Dystonia
Abnormal posture, result of co-contraction of agonist/antagonist muscles. May also have twisting, repetitive movements
Define: Myoclonus
Shock-like movements due to muscle contraction (positive myoclonus) or abrupt loss of muscle tone (negative myoclonus)
Define: Stereotypy
Purposeless repetition of motor set of movements
Define: Tic
Patterned simple or complex paroxysmal movements. Subjective sense of relief after movement
Define: Tremor
Rhythmic movement, with amplitude and frequency in sine wave
Define: Akinesia
lack of purposeful movement
Define: Badykinesia
slowness of movement
Define: Dysdiadochokinesia
Abnormal rapid-alternating movements
Describe the different signs from Medial and Lateral cerebellar lesion
Medial (vermis, fastigial nucleus, flocculonodular lobe): truncal ataxia, nystagmus, head tilting, wide-based gait
Lateral: propensity to fall TOWARD injured side (ipsilateral).
