Diamond A, Goldman-Rakic P S
Section of Neuroanatomy, Yale University School of Medicine, New Haven, CT 06510-8001.
Exp Brain Res. 1989;74(1):24-40. doi: 10.1007/BF00248277.
This paper reports evidence linking dorsolateral prefrontal cortex with one of the cognitive abilities that emerge between 7.5-12 months in the human infant. The task used was Piaget's Stage IV Object Permanence Test, known as AB (pronounced "A not B"). The AB task was administered (a) to human infants who were followed longitudinally and (b) to intact and operated adult rhesus monkeys with bilateral prefrontal and parietal lesions. Human infants displayed a clear developmental progression in AB performance, i.e., the length of delay required to elicit the AB error pattern increased from 2-5 s at 7.5-9 months to over 10 s at 12 months of age. Monkeys with bilateral ablations of dorsolateral prefrontal cortex performed on the AB task as did human infants of 7.5-9 months; i.e., they showed the AB error pattern at delays of 2-5 s and chance performance at 10 s. Unoperated and parietally operated monkeys succeeded at delays of 2, 5, and 10 s; as did 12 month old human infants. AB bears a striking resemblance to Delayed Response, the classic test for dorsolateral prefrontal function in the rhesus monkey, and indeed performance on AB and Delayed Response in the same animals in the present study was fully comparable. These findings provide direct evidence that AB performance depends upon dorsolateral prefrontal cortex in rhesus monkeys and indicates that maturation of dorsolateral prefrontal cortex may underlie the developmental improvement in AB performance of human infants from 7.5-12 months of age. This improvement marks the development of the ability to hold a goal in mind in the absence of external cues, and to use that remembered goal to guide behavior despite the pull of previous reinforcement to act otherwise. This confers flexibility and freedom to choose and control what one does.
本文报告了有关背外侧前额叶皮层与人类婴儿7.5至12个月时出现的一种认知能力之间联系的证据。所使用的任务是皮亚杰的第四阶段客体永久性测试，即A非B任务（发音为“A not B”）。该A非B任务被用于：(a) 对进行纵向跟踪的人类婴儿，以及 (b) 对患有双侧前额叶和顶叶损伤的完整和手术成年恒河猴。人类婴儿在A非B任务表现上呈现出明显的发育进程，即引发A非B错误模式所需的延迟时间从7.5至9个月时的2至5秒增加到12个月大时的超过10秒。双侧背外侧前额叶皮层被切除的猴子在A非B任务中的表现与7.5至9个月大的人类婴儿相同；也就是说，它们在2至5秒的延迟时表现出A非B错误模式，而在10秒时表现为随机水平。未做手术和仅做顶叶手术的猴子在2秒、5秒和10秒的延迟时均成功完成任务；12个月大的人类婴儿也是如此。A非B任务与延迟反应有显著相似之处，延迟反应是恒河猴背外侧前额叶功能的经典测试，实际上在本研究中同一动物在A非B任务和延迟反应任务上的表现完全可比。这些发现提供了直接证据，表明恒河猴的A非B任务表现取决于背外侧前额叶皮层，并表明背外侧前额叶皮层的成熟可能是人类婴儿7.5至12个月时A非B任务表现发育改善的基础。这种改善标志着在没有外部线索的情况下记住目标并利用该记忆目标指导行为的能力的发展，尽管之前的强化作用会促使做出其他行为。这赋予了选择和控制自身行为的灵活性和自由。
