A novel approach to studying the neurobiology of decision-making: modeling cognitive effort in rats

点击翻译按钮获取中文摘要

Understanding the mechanism by which we come to prefer a particular option, and how different factors can influence that decision, is one of the overarching goals of both cognitive and behavioural neuroscience. Laboratory-based paradigms in which a particular factor within a decision frame (delay/ probability/ effort) is systematically varied have provided us with a wealth of information regarding the potential neural, and to some extent, neurochemical systems implicated in different forms of decision-making. By translating these tasks into non-human animal models, it is possible to test the causative relationships suggested by human data, and delineate further the pharmacological and molecular regulation of the choice process. Given that most decisions in this world require allocation of cognitive effort, our proposal addresses the question of whether rats are sensitive to the dimension of mental strain when making decisions, and what neurobiological processes may be involved in the execution of such judgements. To this end, we have developed a novel paradigm- the rat cognitive effort task (R-CET)- in which rats choose whether to perform an attentional demanding task, in which they have to detect the spatial location of a very brief light stimulus, or an easier task, in which the stimulus is illuminated for longer and is therefore easier to localise. Correct performance of a more difficult option leads to a greater amount of reward. Interestingly, there are marked individual differences in the degree to which animals select the harder trials, leading to the classification of animals as either "workers" or "slackers". This classification is independent of animals' ability to perform the hard or easy trials i.e. both workers and slackers are just as accurate at detecting the visual target, regardless of the stimulus duration. Hence, it would appear that we can separate willingness to exert cognitive effort from the ability to perform a more effortful task. The experiments outlined in this proposal aim to build on our initial characterisation of this novel decision-making task, and determine the brain areas, chemicals and molecular signalling pathways involved.