Department of Psychology, University of California, Berkeley, Berkeley, California 94720-1650, USA.
J Neurosci. 2010 Aug 18;30(33):11062-7. doi: 10.1523/JNEUROSCI.6266-09.2010.
Although children perform more poorly than adults on many cognitive measures, they are better able to learn things such as language and music. These differences could result from the delayed specialization of neural circuits and asynchronies in the maturation of neural substrates required for learning. Working memory--the ability to hold information in mind that is no longer present in the environment--comprises a set of cognitive processes required for many, if not all, forms of learning. A critical neural substrate for working memory (the prefrontal cortex) continues to mature through early adulthood. What are the functional consequences of this late maturation for working memory? Using a longitudinal design, we show that although individuals recruit prefrontal cortex as expected during both early and late adolescence during a working memory task, this recruitment is correlated with behavior only in late adolescence. The hippocampus is also recruited, but only during early, and not late, adolescence. Moreover, the hippocampus and prefrontal cortex are coactive in early adolescence regardless of task demands or performance, in contrast to the pattern seen in late adolescents and adults, when these regions are coactive only under high task demands. Together, these data demonstrate that neural circuitry underlying working memory changes during adolescent development. The diminishing contribution of the hippocampus in working memory function with age is an important observation that informs questions about how children and adults learn differently.
虽然儿童在许多认知测试中的表现不如成年人，但他们更能够学习语言和音乐等东西。这些差异可能是由于神经回路的专业化延迟以及学习所需的神经基质的成熟不同步所致。工作记忆——在环境中不再存在的情况下保持信息的能力——是许多学习形式（如果不是全部的话）所必需的一组认知过程。工作记忆的一个关键神经基质（前额叶皮层）在整个成年早期仍在继续成熟。这种晚期成熟对工作记忆有什么功能上的影响？我们使用纵向设计表明，尽管个体在工作记忆任务中，无论是在早期还是晚期青少年期，都如预期那样招募前额叶皮层，但这种招募仅与晚期青少年期的行为相关。海马体也被招募，但仅在早期青少年期，而不是晚期青少年期。此外，海马体和前额叶皮层在早期青少年期无论任务需求或表现如何都是共同活跃的，与晚期青少年期和成年期的模式形成鲜明对比，在这些时期，只有在高任务需求下这些区域才会共同活跃。这些数据共同表明，工作记忆的神经回路在青少年发育期间发生变化。随着年龄的增长，海马体在工作记忆功能中的贡献逐渐减少，这是一个重要的观察结果，它提出了关于儿童和成人如何不同地学习的问题。
