Lecture 11: Cerebellum Flashcards
What is the function of the inferior vermis and the flocculonodular lobes?
Regulation of balance and eye-movements (vestibular circuit).
What is the function of the vermis, apart from the inferior division?
Control of medial motor systems (proximal trunk muscles).
What is the function of the intermediate part of the cerebellar hemispheres?
Control of lateral motor systems (distal appendicular muscles and motor planning).
What is the function of the lateral part of the cerebellar hemispheres?
Planning motor programming of the extremities.
There are three cerebellar peduncles. Name them and describe the associated function.
Superior, middle and inferior cerebellar peduncles. The superior p. is mainly responsible for output, while the middle and inferior cerebellar peduncles are mainly responsible for receiving input.
Describe the vestibular tract from the cerebellum to the cerebral cortex.
Vestibular signals from the inner ear go to the brainstem to the superior, lateral, medial and inferior vestibular nuclei. From there, they travel via the ascending medial longitudinal fasciculus through the ventroposterior nucleus of the thalamus to the cerebral cortex.
Describe the pathway from the lateral cerebellum to the motor- and association cortex. Name one important function of this pathway.
From the dentate nucleus, signals ascend to the ventral lateral nucleus of the thalamus via the superior cerebellar peduncle. From there, the signals are transferred to the motor- and association cortex. One particular function is cognition, especially executive functioning.
Describe the pathway from the lateral cerebellum that is involved in motor learning.
From the dentate nucleus, signals first ascend to the parvocellular division of the red nucleus via the superior cerebellar peduncle. From there, signals descend via the central tegmental tract to the inferior olivary nucleus and finally project back to the cerebellum via the olivocerebellar fibers, forming a “loop”.
Which part of the cerebellum is relevant for the lateral corticospinal and the magnocellular part of the rubrospinal tract?
The intermediate hemispheres of the cerebellum.
Will lesions in the cerebellum lead to contralateral or ipsilateral dysfunctions? Why is that so?
All lesions will lead to ipsilateral dysfunctions, because tracts either remain on the same side, or cross over two times.
What are the main sources of cerebellar input?
Corticopontine fibers from all four lobes via internal capsule and cerebral peduncles, particularly primary sensory and motor cortex, as well as part of visual cortex.
Apart from pontocerebellar fibers, which tracts belong to the main cerebellar input pathways. Name them and describe the function respectively.
(1) Dorsal spinocerebellar tract: lower extremity movements.
(2) Cuneocerebellar tract: upper extremity movements and unconscious information from extremities.
(3) Ventral spinocerebellar tract: leg
(3) Rostral spinocerebellar tract: arm and information about interneuron activity in the spinal cord, reflecting the amount of activity in the descending pathways.
What is a frequent symptom in cases of cerebellar lesions?
Ataxia, ipsilateral to the lesion.
