Advanced Cerebellum Quiz

Q1. Why do cerebellar hemisphere lesions usually produce motor deficits on the same side of the body?

• Cerebellar output and motor pathways are organized so functional effects are predominantly ipsilateral
• All cerebellar fibers remain uncrossed from cortex to muscle
• Each cerebellar hemisphere controls only the contralateral cerebral cortex
• The corticospinal tract never crosses

Q2. Which deep nuclei are collectively called the interposed nuclei?

• Gracile and cuneate nuclei
• Globose and emboliform nuclei
• Fastigial and dentate nuclei
• Dentate and red nuclei

Q3. Which fibers provide powerful excitatory input to Purkinje cells from the inferior olivary complex?

• Purkinje axons
• Climbing fibers
• Corticospinal fibers
• Mossy fibers from pontine nuclei only

Q4. How do mossy fibers influence Purkinje cells?

• By directly forming the dentate nucleus
• By becoming Purkinje cell axons
• By entering the corticospinal tract
• Through granule cells and their parallel fibers

Q5. Where do most superior cerebellar peduncle efferent fibers cross?

• Cervical spinal cord
• Caudal medulla
• Optic chiasm
• Caudal midbrain

Q6. Which arterial branches provide the principal blood supply to the cerebellum?

• Internal thoracic, vertebral, and facial arteries
• ACA, MCA, and PCA only
• SCA, AICA, and PICA
• Anterior spinal, middle meningeal, and ophthalmic arteries

Q7. Why can a midline cerebellar lesion prominently impair stance and gait?

• The vermis contains primary lower motor neurons
• The vermis directly innervates skeletal muscle
• The vermis is strongly involved in axial control and posture
• The vermis is the primary visual cortex

Q8. Why can a lateral cerebellar hemisphere lesion cause dysmetria and intention tremor of an ipsilateral limb?

• It causes complete paralysis by cutting the corticospinal tract
• It destroys lower motor neurons in the anterior horn
• It interrupts the dorsal root ganglion
• It disrupts cerebellar coordination of the timing and scaling of ipsilateral skilled movement

Q9. What is the main output relationship between Purkinje cells and deep cerebellar nuclei?

• Purkinje cells project directly to skeletal muscle
• Purkinje cells excite deep nuclei using glutamate
• Purkinje cells inhibit deep nuclei that generate major cerebellar output
• Deep nuclei inhibit all Purkinje cells as the sole cortical input

Q10. Which statement best integrates cerebellar anatomy?

• It contains no organized cortical layers or deep nuclei
• It is primarily a sensory relay nucleus within the thalamus
• It integrates cortical, sensory, vestibular, and brainstem information through its cortex, deep nuclei, and peduncles to coordinate movement and balance
• It directly initiates all voluntary movement through lower motor neurons