This chapter reviews clinical features (with illustrative video cases)
and pathophysiology of medullary lesions, including Wallenberg’s
syndrome and oculopalatal tremor. Manifestations and pathophysiology
of three cerebellar syndromes are described (flocculus and
paraflocculus, nodulus and ventral uvula, dorsal vermis and fastigial
nucleus), applying these principles to interpret the effects of
developmental disorders (e.g., Chiari malformation), hereditary
ataxia, paraneoplastic cerebellar degeneration, cerebellar stroke, and
cerebellar tumors. Characteristics of pontine lesions are discussed,
including lesions of the abducens nucleus, paramedian pontine
reticular formation (PPRF), internuclear ophthalmoplegia (INO),
one-and-a-half syndrome, slow horizontal saccades, and saccadic
oscillations. The effects of midbrain lesions are summarized,
including lesions affecting the rostral interstitial nucleus of the
medial longitudinal fasciculus (RIMLF), interstitial nucleus of Cajal,
posterior commissure, and more diffuse processes causing slow vertical
saccades or vertical gaze palsy (dorsal midbrain syndrome), including
Whipple’s disease. Effects of lesions affecting the superior
colliculus, thalamus, and pulvinar are also discussed.