Exam 5: cerebellum by ruff Flashcards
What are the three general areas of the cerebellum?
Spinocerebellum, cerebrocerebellum, vestibulocerebellum
Is cerebellar function to ipsilateral or contralateral sides of the body?
Ipsilateral
What are the two divisions of the spinocerebellum?
Vermis and paravermis
What is the vermis of the spinocerebellum responsible for?
Midline movements: posture, stance, gait, visceral function
What is the paravermis of the spinocerebellum responsible for?
Appendicular movements: reaching, grasping
What is the somatotopic organization of the spinocerebellum?
Vermis in middle parts of the body, paravermis is for the appendages
What is the anterior portion of the cerebrocerebellum responsible for?
spatially and temporally complex movements requiring coordination between muscles (dancing, writing, playing musical instruments)
What is the posterior portion of the cerebrocerebellum responsible for?
Cognition and timing of language and social interactions (language and executive function)
What are the general functions of the cerebellum?
Correcting and preventing motor mistakes, ensuring accurate and smooth movements, learning new motor skills
What are the three deep cerebellar nuclei?
Fastigial, Interposed (globus and emboliform), dentate
What areas of the cortex of the cerebellum project to what deep cerebellar nuclei?
Vermis –> fastigial, Paravermis –> Interposed, Lateral hemispheres –> dentate
What are the cell types of the cerebellar cortex?
Purkinje cells, Granule cells (most numerous), inhibitory interneurons (golgi, stellate, basket)
What is the basic circuit of the cerebellar cortex?
parallel fiber contacts purkinje cells that also contacts climbing fibers and deep cerebellar nuclear cells, Mossy fibers connect to parallel fibers and also connect to deep cerebellar nuclear cells. Deep cerebellar fibers to go thalamus
What fibers provide input to the cerebellum?
Mossy fibers and climbing fibers
What do mossy fibers connect to?
Deep cerebellar nuclei, granule cells (parallel fibers)
What do climbing fibers connect to?
deep cerebellar nuclei, purkinje cells
What are sources of mossy fibers?
Spinocerebellum, vestibulocerebellum, cerebrocerebellum
Where do climbing fibers originate?
contralateral inferior olive
Where do the inferior olives receive input that is then sent to the climbing fibers?
parvocellular red nucleus, reticular formation, spinal cord
What are climbing fibers critical for?
Detecting “errors” in motions and comparing input and output
When purkinje cells are firing, what do they do?
inhibit the firing of deep cerebellar nuclei, which in general inhibits movements
What are sources of efference copy that run through spinaocerebellar tracts? Where do they receive their initial stimulus and what is the tract they run in?
Ventral spinocerebellar tract (legs and trunk), rostral spinocerebllar tract (arms)
What are sources of reafference copy that run through spinaocerebellar tracts? Where do they receive their initial stimulus and what is the tract they run in?
Dorsal spinocerebellar tract (legs and trunk), cuneocerebellar tract (arms)
Where does most input to the cerebellum enter through?
Inferior cerebellar peduncle and middle cerebellar peduncle, very little input from superior cerebellar peduncle
Is input from inferior cerebellar peduncle ipsi or contralateral?
ipsilateral (dorsal and rostral spinocerebellar tract, cuneocerebellar, vestibular tract), Contralateral from olivocerebellar tract)
Is input from the middle cerebellar peduncle ipsi or contralateral?
contralateral
Where does most cerebellar output travel through?
Superior cerebellar peduncle
What can cause gait ataxia?
Spinocerebellar ataxia, chronic alcohol abuse
What can deficits of the spinocerebellum result in?
gait ataxia, dysmetria, action tremor, timing disorders, decomposition of movements, inability to adapt to new circumstances
What does deficits in the vestibulocerebellum result in?
Problems with equilibrium and balance (FALL TOWARD SIDE OF LESION), vertigo, vision problems (nystagmus, no smooth eye pursuit, diplopia)
What do deficits in cerebrocerebellum result in?
deficits in fine motor control, inpairment of high skill motions, cognitive deficits (language issues, behavior and affect)
How do outputs of vestibulocerebellum travel?
flocculus and nodulus to vestibular nuclei to vestibular tract
How do cerebrocerebellar outputs travel?
lateral cerebellar hemispheres to dentate nuclei to (contralateral VL thalamus and cortical motor areas) OR (parvocellular red nucleus to inferior olives to climbing fibers)
What are the outputs of cerebrocerebellum responsible for?
coordinating movements under visual or mental guidance, learning complex skilled movements and turning them into “motor memories”
