The use of Doppler shift radar to monitor physiological and drug induced activity patterns in the rat.

Doppler shift radar was used to monitor circadian activity patterns in the rat and to study the behavioural effects of p-chloroamphetamine and d-amphetamine. Activity was classified in two ways:-(a) slow (non-locomotory) and high (locomotory) speed movements. (b) the number of starts of activity, within either the slow or high speed zones of activity during a pre-set time. p-Choloramphetamine (5 mg/kg) produced a biphasic activity response; an initial increase in continuous non-locomotory activity followed by a longer lasting increase in exploratory locomotion containing regular starts of activity. d-Amphetamine (2.5 mg/kg) produced an increase in both non-locomotory and locomotory movements but a marked reduction in starts of activity (i.e. continuous non-exploratory activity). The combination of information on the amount and pattern (starts) of activity allows a more detailed analysis of the effects of drugs on activity to be made than with existing automated methods.