Time-dependent and schedule-dependent effects of dopamine receptor blockade.
Rats were trained on one of two multiple random-interval schedules of reinforcement, which contained both ascending and descending reinforcement density sequences. The design of the schedules made it possible to determine whether performance changes in a particular component depended on the reinforcement density in that component, or on its temporal position within the schedule. Performance impairments following administration of the dopamine D1 antagonist SCH-23390 were both time- and schedule-dependent: SCH-23390 caused a relatively greater suppression of poorly reinforced responding that increased over time. The results, which are compatible with data on the effects of dopamine antagonists in other behavioural paradigms, illustrate the methodological problems of using Herrnstein's matching equation to interpret time-dependent behavioural changes.
Willner
P.
P
Psychology Department, City of London Polytechnic, Old Castle Street, London E1 7NT, UK.
Phillips
G.
G
Sampson
D.
D
Muscat
R.
R