The 5-choice serial reaction time task: behavioural pharmacology and functional neurochemistry

Rationale: The developmental history and application of the 5-choice serial reaction time task (5CSRTT) for measuring effects of drugs and other manipulations on attentional performance (and stimulus control) in rats is reviewed. Objectives: The 5CSRTT has been used for measuring effects of systemic drug treatments and also central manipulations such as neurochemical lesions on various aspects of attentional control, including sustained, selective and divided attention - and is relevant to the definition of neural systems of attention and applications to human disorders such as attention deficit/hyperactivity disorder (ADHD) and Alzheimer's disease. Methods: The 5CSRTT is implemented in a specially designed operant chamber with multiple response locations ('nine-hole box') using food reinforcers to maintain performance on baseline sessions (about 100 trials) at criterion levels of accuracy and trials completed. The 5CSRTT can be used for measuring various aspects of attentional control over performance with its main measures of accuracy, premature responding, correct response latencies and latency to collect earned food pellets. Results: The data reviewed include studies mainly of systemic and intra-cerebral effects of adrenoceptor, dopamine receptor, serotoninergic receptor and cholinergic receptor agents. These are compared with investigations of effects of selective chemical neurotoxins and excitotoxins applied to discrete parts of the forebrain, in order to define the neural and neurochemical substrates of attentional function. Furthermore, these results are integrated with findings from in vivo microdialysis in freely moving rats or metabolic studies. Conclusions: The monoaminergic and cholinergic systems appear to play separable roles in different aspects of performance controlled by the 5CSRTT, in neural systems centred on the prefrontal cortex, cingulate cortex and striatum. These conclusions are considered in the methodological and theoretical context of other psychopharmacological studies of attention in animals and humans.