University of Cambridge, UK.
J Cogn Neurosci. 2012 Nov;24(11):2135-46. doi: 10.1162/jocn_a_00278. Epub 2012 Jul 31.
Age has a differential effect on cognition, with word retrieval being one of the cognitive domains most affected by aging. This study examined the functional and structural neural correlates of phonological word retrieval in younger and older adults using word and picture rhyme judgment tasks. Although the behavioral performance in the fMRI task was similar for the two age groups, the older adults had increased activation in the right pars triangularis across tasks and in the right pars orbitalis for the word task only. Increased activation together with preserved performance in the older participants would suggest that increased activation was related to compensatory processing. We validated this hypothesis by showing that right pars triangularis activation during correct rhyme judgments was highest in participants who made overall more errors, therefore being most error-prone. Our findings demonstrate that the effect of aging differ in adjacent but distinct right inferior frontal regions. The differential effect of age on word and picture tasks also provides new clues to the level of processing that is most affected by age in speech production tasks. Specifically, we suggest that right inferior frontal activation in older participants is needed to inhibit errors.
年龄对认知有差异影响，其中单词检索是受衰老影响最大的认知领域之一。本研究使用单词和图片押韵判断任务，考察了年轻和老年成年人在语音单词检索方面的功能和结构神经相关性。尽管两个年龄组在 fMRI 任务中的行为表现相似，但老年人在跨任务和仅在单词任务中的右侧三角部有更多的激活。增加的激活与老年人的表现保持一致，这表明增加的激活与补偿处理有关。我们通过证明在正确押韵判断期间，右侧三角部的激活在整体错误更多的参与者中最高，因此最容易出错，从而验证了这一假设。我们的研究结果表明，衰老对相邻但不同的右侧下额叶区域的影响不同。年龄对单词和图片任务的不同影响也为言语产生任务中受年龄影响最大的处理水平提供了新的线索。具体来说，我们认为，老年参与者需要右侧下额叶的激活来抑制错误。
