Attentional set-shifting in rodents: a review of behavioural methods and pharmacological results.

Attentional set-shifting tasks have been used as a measure of human fronto-executive function for over 60 years. The major contribution these tasks have made has been the quantification of cognitive deficits associated with human pathologies such as schizophrenia, attention deficit/hyperactivity disorder and dementias related to Parkinson's, Huntington's and Alzheimer's diseases. Thirteen years ago an intradimensional/extradimensional attentional set-shifting task was developed for rats. Since then, there have been over 70 publications detailing the effects of various manipulations on task performance in rats, and 17 publications describing adaptations of the task for mice. Much of this literature has focused on animal models of neuropathology and cognitive deficits associated with schizophrenia and other human conditions. Altogether, these results have elucidated the roles of multiple neurotransmitters in the manifestation of cognitive deficits, and their subsequent amelioration, including dopamine, serotonin, acetylcholine and noradrenaline. However, the fundamental promise of the attentional set-shifting task, to measure cognitive flexibility in humans and rodents in a formally analogous way, has often been under investigated and over simplified. This review explores the research that led to the development of the rat attentional set-shifting task, and how subsequent use of the task has expanded our understanding of the psychological and neurological underpinnings of discrimination and reversal learning, as well as the formation, maintenance and shifting of attentional set.