Minimal brain dysfunction, stimulant drugs, and autonomic nervous system activity.

Autonomic base levels and responsivity to stimuli were investigated in normal and minimally brain dysfunctioned (MBD) children. Continuous recordings of skin conductance, heart rate, skin temperature, and respiration rate were made during rest, at presentation of tones, and when performing a reaction time task. No significant differences in base levels were obtained between normal and MBD children when not taking drugs, but stimulant medication increased skin conductance and heart rate and decreased skin temperature and reaction time. The MBD children were less reactive, autonomically, to all types of stimuli. Stimulant drugs decreased electrodermal responsivity, which was predictable from concurrent changes in base line skin conductance and skintemperature. The MBD performance deficits are not related to lower autonomic responsivity or lower absolute base levels of arousal, but MBD children may perform better at relatively high autonomic base levels.