Morcom Alexa M, Good Catriona D, Frackowiak Richard S J, Rugg Michael D
Institute of Cognitive Neuroscience and Department of Psychology, University College London, London, UK.
Brain. 2003 Jan;126(Pt 1):213-29. doi: 10.1093/brain/awg020.
Event-related functional MRI (fMRI) was used to investigate the neural correlates of memory encoding as a function of age. While fMRI data were obtained, 14 younger (mean age 21 years) and 14 older subjects (mean age 68 years) made animacy decisions about words. Recognition memory for these words was tested at two delays such that older subjects' performance at the short delay was comparable to that of the young subjects at the long delay. This allowed age-associated changes in the neural correlates of encoding to be dissociated from the correlates of differential recognition performance. Activity in left inferior prefrontal cortex and the left hippocampal formation was greater for subsequently recognized words in both age groups, consistent with the findings of previous studies in young adults. In the prefrontal cortex, these 'subsequent memory effects' were, however, left-lateralized in the younger group but bilateral in the older subjects. In addition, for the younger group only, greater activity for remembered words was observed in anterior inferior temporal cortex, as were reversed effects ('subsequent forgetting' effects) in anterior prefrontal regions. The data indicate that older subjects engage much of the same neural circuitry as younger subjects when encoding new memories. However, the findings also point to age-related differences in both prefrontal and temporal activity during successful episodic encoding.
事件相关功能磁共振成像（fMRI）被用于研究作为年龄函数的记忆编码的神经关联。在获取fMRI数据时，14名年轻受试者（平均年龄21岁）和14名年长受试者（平均年龄68岁）对单词做出animate性判断。对这些单词的识别记忆在两个延迟时间进行测试，以使年长受试者在短延迟时的表现与年轻受试者在长延迟时的表现相当。这使得编码的神经关联中与年龄相关的变化能够与不同识别表现的关联区分开来。在两个年龄组中，左前额叶下回和左侧海马结构中对于随后被识别的单词的活动都更强，这与之前在年轻成年人中的研究结果一致。然而，在前额叶皮层，这些“后续记忆效应”在年轻组中是左侧化的，而在年长受试者中是双侧的。此外，仅在年轻组中，在颞下回前部观察到对记忆单词有更强的活动，在前额叶前部区域也观察到相反的效应（“后续遗忘”效应）。数据表明，年长受试者在编码新记忆时使用的神经回路与年轻受试者大致相同。然而，研究结果也指出了在成功的情景编码过程中，前额叶和颞叶活动存在与年龄相关的差异。
