[Jackson's theories on the nature of motor symptoms]

Of John Hughlings Jackson's many contributions to neurological symptomatology, three motor symptoms serve as illustrations of his greatness: convulsions beginning unilaterally with the "march of spasms" (later called Jacksonian epilepsy), tetanus-like seizures (later called Jacksonian cerebellar fits), and cerebellar attitude (later absorbed into the category of "decerebrate rigidity"). The author has summarized their clinical characteristics and the underlying pathophysiological mechanisms as originally described by Jackson. His unique theory of "amicable antagonism" between the cerebrum and the cerebellum is also discussed. This dynamic concept can be considered a forerunner of theories of "rivalry" between higher brain centers.