Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093-0664, USA.
J Int Neuropsychol Soc. 2013 Jul;19(6):625-34. doi: 10.1017/S1355617713000246. Epub 2013 Mar 5.
Functional magnetic resonance imaging (fMRI) studies have identified consistent age-related changes during various cognitive tasks, such that older individuals display more positive and less negative task-related activity than young adults. Recently, evidence shows that chronic physical exercise may alter aging-related changes in brain activity; however, the effect of exercise has not been studied for the neural substrates of language function. Additionally, the potential mechanisms by which aging alters neural recruitment remain understudied. To address these points, the present study enrolled elderly adults who were either sedentary or physically active to characterize the neural correlates of language function during semantic fluency between these groups in comparison to a young adult sample. Participants underwent fMRI during semantic fluency and transcranial magnetic stimulation to collect the ipsilateral silent period, a measure of interhemispheric inhibition. Results indicated that sedentary older adults displayed reductions in negative task-related activity compared to the active old group in areas of the attention network. Longer interhemispheric inhibition was associated with more negative task-related activity in the right and left posterior perisylvian cortex, suggesting that sedentary aging may result in losses in task facilitatory cortical inhibition. However, these losses may be mitigated by regular engagement in physical exercise.
功能磁共振成像（fMRI）研究在各种认知任务中发现了一致的与年龄相关的变化，即老年人的任务相关活动比年轻人更积极，更少消极。最近，有证据表明，慢性体育锻炼可能会改变与年龄相关的大脑活动变化；然而，对于语言功能的神经基础，锻炼的影响尚未得到研究。此外，年龄如何改变神经募集的潜在机制仍研究不足。为了解决这些问题，本研究招募了久坐不动的老年人或积极锻炼的老年人，以描述这些群体与年轻成人样本之间在语义流畅性期间语言功能的神经相关性。参与者在语义流畅性和经颅磁刺激下接受 fMRI，以收集同侧静息期，这是衡量半球间抑制的一种方法。结果表明，与积极锻炼的老年组相比，久坐不动的老年组在注意力网络的区域中显示出与任务相关的负性活动减少。更长的半球间抑制与右侧和左侧后外侧脑回的与任务相关的负性活动增加相关，表明久坐不动的衰老可能导致任务促进性皮质抑制的丧失。然而，经常进行体育锻炼可能会减轻这些损失。
