Age-related changes in brain function are complex. Although ageing is associated with a reduction in cerebral blood flow and neuronal activity, task-related processing is often correlated with an enlargement of the corresponding and additionally recruited brain areas. This supplemental employment is considered an attempt to compensate for deficits in the ageing brain. Although there are contradictory reports regarding the role of the primary somatosensory cortex (SI), currently, there is little knowledge about age-related functional changes in other brain areas in the somatosensory network (secondary somatosensory cortex (SII), and insular, anterior (ACC) and posterior cingulate cortices (PCC)). We investigated 16 elderly (age range, 62-71 years) and 18 young subjects (age range, 21-28 years) by determining the current perception threshold (CPT) and applying functional magnetic resonance imaging (fMRI) using a 3.0 Tesla scanner under tactile stimulation of the right hand. CPT was positively correlated with age. fMRI analysis revealed significantly increased activation in the contralateral SI and ipsilateral motor cortex in elderly subjects. Furthermore, we demonstrated age-related reductions in the activity in the SII, ACC, PCC, and dorsal parts of the corpus callosum. Our study revealed dramatic age-related differences in the processing of a simple tactile stimulus in the somatosensory network. Specifically, we detected enhanced activation in the contralateral SI and ipsilateral motor cortex assumingly caused by deficient inhibition and decreased activation in later stages of somatosensory processing (SII, cingulate cortex) in elderly subjects. These results indicate that, in addition to over-activation to compensate for impaired brain functions, there are complex mechanisms of modified inhibition and excitability involved in somatosensory processing in the ageing brain.

译文

:与年龄相关的脑功能变化非常复杂。尽管衰老与脑血流量和神经元活动的减少有关,但与任务相关的处理过程通常与相应的和额外招募的大脑区域的扩大有关。这种补充性就业被认为是对衰老脑部缺陷的补偿。尽管关于主要体感皮层(SI)的作用有相互矛盾的报道,但目前,关于体感网络(次要体感皮层(SII)和岛状,前侧( ACC)和后扣带回皮质(PCC))。我们通过确定当前知觉阈值(CPT)并使用3.0 Tesla扫描仪应用功能磁共振成像(fMRI)在以下条件下对16位老年人(年龄范围为62-71岁)和18位年轻受试者(年龄范围为21-28岁)进行了调查右手的触觉刺激。 CPT与年龄呈正相关。 fMRI分析显示,老年受试者对侧SI和同侧运动皮层的激活显着增加。此外,我们证明了与年龄有关的SII,ACC,PCC和call体背部活动减少。我们的研究揭示了在体感网络中简单触觉刺激的处理过程中与年龄有关的戏剧性差异。具体而言,我们检测到对侧SI和同侧运动皮层的激活增强,推测是由于抑制作用不足引起的,而在老年受试者的体感处理后期(SII,扣带回皮层)的激活降低。这些结果表明,除了过度激活以补偿受损的脑功能外,衰老的大脑的体感处理还涉及复杂的抑制和兴奋性机制。

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