Dynamic changes in brain activation during task-switching: the effects of development and practice

认知控制是指在面对意想不到的挑战时能够快速调整知觉和运动的过程，与大脑皮质和皮质下区域的广泛网络活动有关。例如，在任务切换范式中，参与者以一种方式(例如，通过颜色)对刺激进行分类，并被周期性地要求以新的方式(例如，通过形状)对相同的刺激进行切换和分类。任务转换范式具有挑战性，特别是对年幼的儿童来说，与重复试验相比，他们在转换时表现出夸大的行为反应时间和准确性成本。随着发展，这类调整变得更容易，因为它们需要更小的性能成本。尽管最近取得了进展，但关于转换成本的性质以及其中与年龄相关的变化的基本问题仍然悬而未决。例如，发展认知神经科学模型将转换成本大小的年龄相关变化与外侧前额叶皮质(LPFC)功能组织的变化联系起来。LPFC对于快速行为调整至关重要，它在局部解剖以及与更大的认知控制网络的功能和结构整合方面都遵循着一条漫长的发展轨迹。因此，大脑组织的成熟性限制使得儿童很难在任务驱动下调节各种知觉和运动区的活动。同时，儿童执行任务转换等心理操作的经验较少。考虑到交换成本因实践而减弱，这一点是相关的。因此，拟议的方案将解决4个基本问题。首先，在任务转换过程中发生的知觉和运动适应的本质是什么？第二，这些适应的性质(即适应的速度、强度)是否与年龄有关？第三，这些适应受到实践的影响吗？第四，练习对年轻和年长的参与者是否产生了类似的影响？了解认知和行为自我调节的发展是重要的科学目标。拟议中的研究将有助于实现这一目标，通过澄清为什么随着年龄的增长，儿童可以更快地适应意想不到的认知行为挑战。

Cognitive control refers to processes that enable rapid perceptual and motor adjustments in the face of unexpected challenges and are associated with activity in a broad network of cortical and subcortical brain areas. In task-switching paradigms, for example, participants classify stimuli one way (e.g., by colour) and are periodically required to switch and classify the same stimuli in a new way (e.g., by shape). Task-switching paradigms are challenging, especially for young children, who show exaggerated behavioral response time and accuracy costs on switch as compared to repeat trials. With development, adjustments of this kind become easier insofar as they exact smaller performance costs. Despite recent progress, basic questions concerning the nature of switch costs and age-related changes therein remain open. Developmental cognitive neuroscience models, for example, link age-related changes in the magnitude of switch costs to changes in the functional organization of lateral prefrontal cortex (lPFC). lPFC, critical for rapid behavioural adjustments, follows a protracted developmental trajectory both in terms of its local anatomy and its functional and structural integration with larger cognitive control networks. On this account, maturational constraints in brain organization make it difficult for children to modulate activity in various perceptual and motor regions driven by a task. At the same time, children have less experience performing mental operations such as task-switching. This is relevant given that switch costs are attenuated by practice. The proposed program will therefore address 4 basic questions. First, what is the nature of perceptual and motor adaptations that occur during task-switching? Second, are there age-related differences in the nature (i.e., rate, strength) of these adaptations? Third, are these adaptations influenced by practice? And fourth, does practice exert comparable effects on younger and older participants? Understanding the development of cognitive and behavioral self-regulation are important scientific objectives. The proposed studies would help achieve this goal, by clarifying why, with age, children can more rapidly adapt to unexpected cognitive-behavioural challenges.