Beese Caroline, Vassileiou Benedict, Friederici Angela D, Meyer Lars
Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
Research Group Language Cycles, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
Front Aging Neurosci. 2019 Jul 17;11:183. doi: 10.3389/fnagi.2019.00183. eCollection 2019.
When sentence processing taxes verbal working memory, comprehension difficulties arise. This is specifically the case when processing resources decline with advancing adult age. Such decline likely affects the encoding of sentences into working memory, which constitutes the basis for successful comprehension. To assess age differences in encoding-related electrophysiological activity, we recorded the electroencephalogram from three age groups (24, 43, and 65 years). Using an auditory sentence comprehension task, age differences in encoding-related oscillatory power were examined with respect to the accuracy of the given response. That is, the difference in oscillatory power between correctly and incorrectly encoded sentences, yielding subsequent memory effects (SME), was compared across age groups. Across age groups, we observed an age-related SME inversion in the alpha band from a power decrease in younger adults to a power increase in older adults. We suggest that this SME inversion underlies age-related comprehension difficulties. With alpha being commonly linked to inhibitory processes, this shift may reflect a change in the cortical inhibition-disinhibition balance. A cortical disinhibition may imply enriched sentence encoding in younger adults. In contrast, resource limitations in older adults may necessitate an increase in cortical inhibition during sentence encoding to avoid an information overload. Overall, our findings tentatively suggest that age-related comprehension difficulties are associated with alterations to the electrophysiological dynamics subserving general higher cognitive functions.
当句子处理对言语工作记忆造成负担时，就会出现理解困难。随着成年人年龄的增长，处理资源下降时，情况尤其如此。这种下降可能会影响句子在工作记忆中的编码，而这是成功理解的基础。为了评估与编码相关的电生理活动中的年龄差异，我们记录了三个年龄组（24岁、43岁和65岁）的脑电图。使用听觉句子理解任务，根据给定反应的准确性，研究了与编码相关的振荡功率的年龄差异。也就是说，比较了正确编码和错误编码句子之间的振荡功率差异，从而产生后续记忆效应（SME），并在各年龄组之间进行了比较。在各年龄组中，我们观察到α波段中与年龄相关的SME反转，即从年轻人的功率下降到老年人的功率增加。我们认为这种SME反转是与年龄相关的理解困难的基础。由于α通常与抑制过程相关，这种转变可能反映了皮质抑制-去抑制平衡的变化。皮质去抑制可能意味着年轻人的句子编码更加丰富。相比之下，老年人的资源限制可能需要在句子编码过程中增加皮质抑制，以避免信息过载。总体而言，我们的研究结果初步表明，与年龄相关的理解困难与支持一般高级认知功能的电生理动力学变化有关。
