Sala-Llonch Roser, Arenaza-Urquijo Eider M, Valls-Pedret Cinta, Vidal-Piñeiro Dídac, Bargalló Nuria, Junqué Carme, Bartrés-Faz David
Departament de Psiquiatria i Psicobiologia Clinica, Facultat de Medicina, Universitat de Barcelona Barcelona, Spain.
Front Hum Neurosci. 2012 Jun 7;6:152. doi: 10.3389/fnhum.2012.00152. eCollection 2012.
In recent years, several theories have been proposed in attempts to identify the neural mechanisms underlying successful cognitive aging. Old subjects show increased neural activity during the performance of tasks, mainly in prefrontal areas, which is interpreted as a compensatory mechanism linked to functional brain efficiency. Moreover, resting-state studies have concluded that elders show disconnection or disruption of large-scale functional networks. We used functional MRI during resting-state and a verbal n-back task with different levels of memory load in a cohort of young and old healthy adults to identify patterns of networks associated with working memory and brain default mode. We found that the disruption of resting-state networks in the elderly coexists with task-related overactivations of certain brain areas and with reorganizations within these functional networks. Moreover, elders who were able to activate additional areas and to recruit a more bilateral frontal pattern within the task-related network achieved successful performance on the task. We concluded that the balanced and plastic reorganization of brain networks underlies successful cognitive aging. This observation allows the integration of several theories that have been proposed to date regarding the aging brain.
近年来，人们提出了几种理论，试图确定成功认知老化背后的神经机制。老年受试者在执行任务时神经活动增加，主要在前额叶区域，这被解释为一种与大脑功能效率相关的补偿机制。此外，静息态研究得出结论，老年人表现出大规模功能网络的断开或破坏。我们在一组年轻和老年健康成年人中，使用静息态功能磁共振成像和具有不同记忆负荷水平的言语n-back任务，以识别与工作记忆和大脑默认模式相关的网络模式。我们发现，老年人静息态网络的破坏与某些脑区与任务相关的过度激活以及这些功能网络内的重组并存。此外，能够在与任务相关的网络中激活额外区域并形成更双侧额叶模式的老年人在任务中取得了成功表现。我们得出结论，大脑网络的平衡和可塑性重组是成功认知老化的基础。这一观察结果使得迄今为止提出的关于衰老大脑的几种理论得以整合。
