Nilsson Jonna, Berggren Rasmus, Garzón Benjamín, Lebedev Alexander V, Lövdén Martin
Aging Research Center, Karolinska Institute (KI), Stockholm University, Stockholm, Sweden.
Department of Physical Activity and Health, Swedish School of Sport and Health Sciences, Stockholm, Sweden.
Front Aging Neurosci. 2021 Jun 3;13:666851. doi: 10.3389/fnagi.2021.666851. eCollection 2021.
It has previously been demonstrated that short-term foreign language learning can lead to structural brain changes in younger adults. Experience-dependent brain plasticity is known to be possible also in older age, but the specific effect of foreign language learning on brain structure in language-and memory-relevant regions in the old brain remains unknown. In the present study, 160 older Swedish adults (65-75 years) were randomized to complete either an entry-level Italian course or a relaxation course, both with a total duration of 11 weeks. Structural MRI scans were conducted before and after the intervention in a subset of participants to test for differential change in gray matter in the two groups in the inferior frontal gyrus, the superior temporal gyrus, and the hippocampus, and in white matter microstructure in the superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus (ILF), fronto-occipital fasciculus, and the hippocampal (HC) section of the cingulum. The study found no evidence for differential structural change following language training, independent of achieved vocabulary proficiency. However, hippocampal volume and associative memory ability before the intervention were found to be robust predictors of vocabulary proficiency at the end of the language course. The results suggest that having greater hippocampal volume and better associative memory ability benefits vocabulary learning in old age but that the very initial stage of foreign language learning does not trigger detectable changes in brain morphometry in old age.
此前已有研究表明，短期外语学习可使年轻成年人的大脑结构发生变化。众所周知，依赖经验的大脑可塑性在老年人中也有可能存在，但外语学习对老年人大脑中与语言和记忆相关区域的脑结构的具体影响尚不清楚。在本研究中，160名65至75岁的瑞典老年人被随机分为两组，一组完成入门级意大利语课程，另一组完成放松课程，两组课程总时长均为11周。对部分参与者在干预前后进行了结构磁共振成像扫描，以测试两组在额下回、颞上回和海马体中的灰质差异变化，以及在弓状束、下纵束、额枕束和扣带回海马段中的白质微观结构差异变化。研究发现，无论词汇掌握程度如何，语言训练后均未发现有结构差异变化的证据。然而，干预前的海马体体积和联想记忆能力被发现是语言课程结束时词汇掌握程度的有力预测指标。结果表明，海马体体积较大和联想记忆能力较好有助于老年人的词汇学习，但外语学习的最初阶段不会引发老年人大脑形态测量学上可检测到的变化。
