Lise Meitner Research Group Cognition and Plasticity, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
Department of Psychology, University of Lübeck, Lübeck, Germany; Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, Germany.
Cortex. 2022 Sep;154:269-286. doi: 10.1016/j.cortex.2022.05.020. Epub 2022 Jun 14.
Speech comprehension is often challenged by increased background noise, but can be facilitated via the semantic context of a sentence. This predictability gain relies on an interplay of language-specific semantic and domain-general brain regions. However, age-related differences in the interactions within and between semantic and domain-general networks remain poorly understood. Using functional neuroimaging, we investigated commonalities and differences in network interactions enabling processing of degraded speech in healthy young and old participants. Participants performed a sentence repetition task while listening to sentences with high and low predictable endings and varying intelligibility. Stimulus intelligibility was adjusted to individual hearing abilities. Older adults showed an undiminished behavioural predictability gain. Likewise, both groups recruited a similar set of semantic and cingulo-opercular brain regions. However, we observed age-related differences in effective connectivity for high predictable speech of increasing intelligibility. Young adults exhibited stronger connectivity between regions of the cingulo-opercular network and between left insula and the posterior middle temporal gyrus. Moreover, these interactions were excitatory in young adults but inhibitory in old adults. Finally, the degree of the inhibitory influence between cingulo-opercular regions was predictive of the behavioural sensitivity towards changes in intelligibility for high predictable sentences in older adults only. Our results demonstrate that the predictability gain is relatively preserved in older adults when stimulus intelligibility is individually adjusted. While young and old participants recruit similar brain regions, differences manifest in underlying network interactions. Together, these results suggest that ageing affects the network configuration rather than regional activity during successful speech comprehension under challenging listening conditions.
言语理解通常会受到背景噪声的影响，但可以通过句子的语义语境得到促进。这种可预测性的提高依赖于语言特定的语义和领域普遍的大脑区域之间的相互作用。然而，年龄相关的语义和领域普遍网络内和网络间相互作用的差异仍然知之甚少。我们使用功能神经影像学研究了健康的年轻和老年参与者在处理退化语音时网络相互作用的共性和差异。参与者在听具有高和低可预测结尾且可懂度不同的句子时执行句子重复任务。根据个人的听力能力调整刺激的可懂度。老年人表现出行为可预测性增益没有减弱。同样，两组都招募了一组相似的语义和扣带前回脑区。然而，我们观察到随着高可预测性语音的可懂度增加，有效连通性在年龄相关方面存在差异。年轻成年人表现出扣带前回网络区域之间以及左岛叶和后颞中回之间更强的连接。此外，这些相互作用在年轻成年人中是兴奋性的，而在老年人中是抑制性的。最后，扣带前回区域之间的抑制性影响程度是预测老年人对高可预测句子的可懂度变化的行为敏感性的唯一因素。我们的研究结果表明，当刺激可懂度进行个体化调整时，老年人的可预测性增益相对保留。虽然年轻和老年参与者招募了相似的大脑区域，但差异表现在潜在的网络相互作用中。综上所述，这些结果表明，在具有挑战性的听力条件下，成功进行言语理解时，年龄会影响网络配置，而不是区域活动。
