Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Neurobiol Aging. 2011 Aug;32(8):1505-13. doi: 10.1016/j.neurobiolaging.2009.08.015. Epub 2009 Sep 25.
Alterations of existing neural networks during healthy aging, resulting in behavioral deficits and changes in brain activity, have been described for cognitive, motor, and sensory functions. To investigate age-related changes in the neural circuitry underlying overt non-lexical speech production, functional MRI was performed in 14 healthy younger (21-32 years) and 14 healthy older individuals (62-84 years). The experimental task involved the acoustically cued overt production of the vowel /a/ and the polysyllabic utterance /pataka/. In younger and older individuals, overt speech production was associated with the activation of a widespread articulo-phonological network, including the primary motor cortex, the supplementary motor area, the cingulate motor areas, and the posterior superior temporal cortex, similar in the /a/ and /pataka/ condition. An analysis of variance with the factors age and condition revealed a significant main effect of age. Irrespective of the experimental condition, significantly greater activation was found in the bilateral posterior superior temporal cortex, the posterior temporal plane, and the transverse temporal gyri in younger compared to older individuals. Significantly greater activation was found in the bilateral middle temporal gyri, medial frontal gyri, middle frontal gyri, and inferior frontal gyri in older vs. younger individuals. The analysis of variance did not reveal a significant main effect of condition and no significant interaction of age and condition. These results suggest a complex reorganization of neural networks dedicated to the production of speech during healthy aging.
在健康衰老过程中，现有的神经网络发生改变，导致行为缺陷和大脑活动变化，这已在认知、运动和感觉功能方面得到描述。为了研究与明显非词汇言语产生相关的神经回路的年龄相关性变化，对 14 名健康的年轻个体（21-32 岁）和 14 名健康的老年个体（62-84 岁）进行了功能磁共振成像（fMRI）检查。实验任务涉及听觉提示的明显元音/a/和多音节词/pataka/的产生。在年轻和老年个体中，明显的言语产生与广泛的发音-语音网络的激活有关，包括初级运动皮层、辅助运动区、扣带运动区和后上颞叶皮层，在/a/和/pataka/条件下相似。方差分析的因素为年龄和条件，结果显示年龄有显著的主效应。无论实验条件如何，与老年个体相比，年轻个体的双侧后上颞叶皮层、后颞平面和横颞回的激活明显更强。与年轻个体相比，老年个体的双侧颞中回、内侧额回、额中回和额下回的激活明显更强。方差分析未显示条件的显著主效应，也未显示年龄和条件的显著交互作用。这些结果表明，在健康衰老过程中，言语产生所涉及的神经网络发生了复杂的重组。
