Tremblay Pascale, Sato Marc, Deschamps Isabelle
Université Laval, Departement de Readaptation, Faculté de Medecine, Quebec City, Quebec, Canada.
Centre de Recherche de l'Institut Universitaire en Sante Mentale de Québec, Quebec City, Quebec, Canada.
Hum Brain Mapp. 2017 May;38(5):2751-2771. doi: 10.1002/hbm.23558. Epub 2017 Mar 6.
Healthy aging is associated with a decline in cognitive, executive, and motor processes that are concomitant with changes in brain activation patterns, particularly at high complexity levels. While speech production relies on all these processes, and is known to decline with age, the mechanisms that underlie these changes remain poorly understood, despite the importance of communication on everyday life. In this cross-sectional group study, we investigated age differences in the neuromotor control of speech production by combining behavioral and functional magnetic resonance imaging (fMRI) data. Twenty-seven healthy adults underwent fMRI while performing a speech production task consisting in the articulation of nonwords of different sequential and motor complexity. Results demonstrate strong age differences in movement time (MT), with longer and more variable MT in older adults. The fMRI results revealed extensive age differences in the relationship between BOLD signal and MT, within and outside the sensorimotor system. Moreover, age differences were also found in relation to sequential complexity within the motor and attentional systems, reflecting both compensatory and de-differentiation mechanisms. At very high complexity level (high motor complexity and high sequence complexity), age differences were found in both MT data and BOLD response, which increased in several sensorimotor and executive control areas. Together, these results suggest that aging of motor and executive control mechanisms may contribute to age differences in speech production. These findings highlight the importance of studying functionally relevant behavior such as speech to understand the mechanisms of human brain aging. Hum Brain Mapp 38:2751-2771, 2017. © 2017 Wiley Periodicals, Inc.
健康衰老与认知、执行和运动过程的衰退相关，这些衰退与大脑激活模式的变化同时出现，尤其是在高复杂程度水平时。虽然言语产生依赖于所有这些过程，并且已知会随着年龄增长而衰退，但尽管交流在日常生活中很重要，这些变化背后的机制仍知之甚少。在这项横断面组研究中，我们通过结合行为和功能磁共振成像（fMRI）数据，研究了言语产生的神经运动控制中的年龄差异。27名健康成年人在执行一项言语产生任务时接受了fMRI检查，该任务包括说出不同序列和运动复杂程度的非单词。结果表明，在运动时间（MT）方面存在显著的年龄差异，老年人的MT更长且更具变异性。fMRI结果显示，在感觉运动系统内外，血氧水平依赖（BOLD）信号与MT之间的关系存在广泛的年龄差异。此外，在运动和注意力系统内，与序列复杂性相关的年龄差异也被发现，这反映了补偿和去分化机制。在非常高的复杂程度水平（高运动复杂性和高序列复杂性）下，MT数据和BOLD反应中均发现了年龄差异，这种差异在几个感觉运动和执行控制区域有所增加。总之，这些结果表明，运动和执行控制机制的老化可能导致言语产生中的年龄差异。这些发现凸显了研究功能相关行为（如言语）以理解人类大脑老化机制的重要性。《人类大脑图谱》38:2751 - 2771, 2017。© 2017威利期刊公司。
