Department of Psychology, University of British Columbia, Vancouver, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada.
Department of Psychology, University of British Columbia, Vancouver, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada.
Neuropharmacology. 2018 Jul 15;137:322-331. doi: 10.1016/j.neuropharm.2018.04.025. Epub 2018 Apr 24.
Cognitive effort is a ubiquitous process, yet surprisingly little is known about the brain mechanisms responsible for evaluating it. Here, we utilize the rat Cognitive Effort Task (rCET) to probe the striatum's role in deciding between options that vary in the amount of cognitive effort required for success. In the rCET, animals choose to perform either an easy trial, in which the attentional demand is low but the potential reward is small, or a difficult trial which is more attentionally demanding but can yield twice the sugar pellets. Twenty-six male Long Evans rats were trained on the rCET and the effects of pharmacologically inactivating the dorsomedial striatum (DMS) and core region of the nucleus accumbens were determined. Temporary inactivation of the DMS decreased all animals' choice of the high-effort, high-reward option, impaired attentional accuracy, and robustly increased premature responding without impairing general indices of motor ability. The DMS therefore appears necessary for the integration of cognitive signals required for optimal performance. In stark contrast, following temporary inactivation of the ventral striatum, subjects were fundamentally unable to perform the task, as reflected by a drastic decrease in the number of trials initiated and an increase in omitted responses. Together, these data suggest the striatum is likely part of a larger cortico-limbic-striatal network whose function is to optimize decisions requiring cognitive effort costs, at least in the attentional domain, and that striatal subregions have dissociable roles in the adjudication and application of this form of cognitive effort.
认知努力是一种普遍存在的过程，但令人惊讶的是，人们对负责评估认知努力的大脑机制知之甚少。在这里，我们利用大鼠认知努力任务（rCET）来探究纹状体在决定需要不同认知努力程度的成功选项时的作用。在 rCET 中，动物选择执行简单的任务，其中注意力需求较低，但潜在奖励较小，或者执行困难的任务，注意力需求较高，但可以获得两倍的糖丸。26 只雄性长耳兔被训练在 rCET 上，并确定了药理学失活背内侧纹状体（DMS）和伏隔核核心区域对其的影响。DMS 的短暂失活降低了所有动物对高努力、高回报选项的选择，损害了注意力的准确性，并强烈增加了过早反应，而不损害一般运动能力的指标。因此，DMS 似乎是整合最佳表现所需认知信号所必需的。相比之下，腹侧纹状体的短暂失活后，被试者根本无法完成任务，这反映在启动的试验次数急剧减少和遗漏反应增加。总的来说，这些数据表明纹状体可能是皮质 - 边缘 - 纹状体网络的一部分，其功能是优化需要认知努力成本的决策，至少在注意力领域，而纹状体的不同亚区在这种形式的认知努力的裁决和应用中具有不同的作用。
