Internal Manipulation of Perceptual Representations in Human Flexible Cognition: A Computational Model

Executive functions represent a wide set of goal-directed cognitive processes that rely on integrated cortical-basal ganglia brain systems and are at the basis of human flexible behaviour. Several computational models have been proposed to study cognitive flexibility and the Wisconsin Card Sorting Test (WCST), an important neuropsychological test used for measuring such function. These models clarify important aspects of cognitive flexibility, in particular the processes concerning decision making, motor response, and feedback-dependent learning. However, several studies suggest that categorisation processes, as those involved in the solution of the WCST, also involve a fundamental category representation stage supporting the other processes. Surprisingly, all models of the WCST ignore such fundamental stage and propose that decision making directly triggers actions. Here we propose a novel hypothesis for which the key element of cognitive flexibility resides on the acquisition of suitable representations of percepts, and their top-down internal manipulation, to prepare effective actions. We also propose a neuro-inspired computational model to operationalise the hypothesis. The model is validated by systematically reproducing and interpreting the behaviour of healthy young and old adults, and of frontal and Parkinson pathological patients. The hypothesis and model also allow the proposal of a new version of the WCST that might be used to further investigate the important role of the internal manipulation of representations here proposed to be at the core of flexible goal-directed behaviour.