morphol./histopathol. changes: histological examination of the brain of one of the two monkeys
cognitive/behavioral endpoints: performance of a four-choice forced-choice serial reaction task (monkeys had to move a lever in the direction indicated by the light for food reward)
No effects were observed below a dose rate of 10 W. Above this level, behavioral suppression occured. Correct response rate was deeply altered. The effect was reversible and repeatable in one of the monkeys,- the other monkey did not recover completely and was sacrified for histological examination which revealed no gross or microscopic damage. The nature of the effect suggests a neurochemical rather than an electrical or mechanical basis for the findings.