This volume presents the latest knowledge on physiological substrates for a number of well-known cortical and behavioural mechanisms. The book covers negative motor phenomena and addresses a significant range of cortical and subcortial interactions and their responses to external modulation. The book opens with a section focusing on clinical syndromes, including both generalized and and focal atonic seizures, drop attacks and negative chorea, the freezing phenomena in parkinsonism, and cataplexy. The next major section addresses cortical mechanisms and covers such areas as transcranial magnetic stimulation; cortical electrical stimulation in both humans and monkeys; and the physiology of cortical spread, cortical-subcortical spread, rhythmicity, asterixis and negative myoclonus. The following section, devoted to brainstem mechanisms, explores anatomy and transmitters of motor systems, as well as the physiology of REM sleep and cataplexy, startle phenomena and postural control. Subsequent sections examine spinal cord mechanisms and discuss the mechanisms of action and the use of a variety of drugs used in seizure control.