Heuninckx Sofie, Wenderoth Nicole, Swinnen Stephan P
Motor Control Laboratory, Group Biomedical Sciences, K.U. Leuven, B-3001 Heverlee, Belgium.
J Neurosci. 2008 Jan 2;28(1):91-9. doi: 10.1523/JNEUROSCI.3300-07.2008.
Functional imaging studies have shown that seniors exhibit more elaborate brain activation than younger controls while performing motor tasks. Here, we investigated whether this age-related overactivation reflects compensation or dedifferentiation mechanisms. "Compensation" refers to additional activation that counteracts age-related decline of brain function and supports successful performance, whereas "dedifferentiation" reflects age-related difficulties in recruiting specialized neural mechanisms and is not relevant to task performance. To test these predictions, performance on a complex interlimb coordination task was correlated with brain activation. Findings revealed that coordination resulted in activation of classical motor coordination regions, but also higher-level sensorimotor regions, and frontal regions in the elderly. Interestingly, a positive correlation between activation level in these latter regions and motor performance was observed in the elderly. This performance enhancing additional recruitment is consistent with the compensation hypothesis and characterizes neuroplasticity at the systems level in the aging brain.
功能成像研究表明，老年人在执行运动任务时，大脑激活比年轻对照组更为复杂。在此，我们研究了这种与年龄相关的过度激活是反映了代偿机制还是去分化机制。“代偿”是指额外的激活，它抵消了与年龄相关的脑功能衰退并支持成功的表现，而“去分化”反映了在招募专门神经机制方面与年龄相关的困难，并且与任务表现无关。为了检验这些预测，一项复杂的肢体间协调任务的表现与大脑激活相关联。研究结果显示，协调导致老年人经典运动协调区域、更高级别的感觉运动区域以及额叶区域的激活。有趣的是，在老年人中观察到这些后一类区域的激活水平与运动表现之间呈正相关。这种增强表现的额外招募与代偿假说一致，并表征了衰老大脑系统水平的神经可塑性。
