School of Psychology, The University of Queensland, St Lucia, Australia.
School of Psychology, The University of Queensland, St Lucia, Australia.
Neuropsychologia. 2021 Jul 30;158:107891. doi: 10.1016/j.neuropsychologia.2021.107891. Epub 2021 May 15.
The ability to process multiple sources of information concurrently is particularly impaired as individuals age and such age-related increases in multitasking costs have been linked to impairments in response selection. Previous neuroimaging studies with young adults have implicated the left hemisphere prefrontal cortex (PFC) as a key neural substrate of response selection. In addition, several transcranial direct current stimulation (tDCS) studies have provided causal evidence implicating this region in response selection and multitasking operations. For example, Filmer et al. (2013b) demonstrated that typically observed response selection learning/training gains in young adults were disrupted via offline tDCS of left, but not right, PFC. Here, considering evidence of age-related structural and functional changes in the brains of older adults, we assessed if this pattern of response selection learning disruption via tDCS to the left PFC is observed in older adults, testing if this region remains a key response selection node as individuals age. In a pre-registered study with 58 older adults, we applied anodal, cathodal, and sham stimulation to left and right PFC, and measured performance as participants trained on low- and high-response selection load tasks. Active stimulation did not disrupt training in older adults as compared to younger adults from our previous study. The results highlight age-related differences in the casual neural substrates that subserve response selection and learning.
同时处理多个信息源的能力会随着个体年龄的增长而显著下降，这种与年龄相关的多重任务成本增加与反应选择的损伤有关。以前对年轻人的神经影像学研究表明，左半球前额叶皮层（PFC）是反应选择的关键神经基质。此外，几项经颅直流电刺激（tDCS）研究提供了因果证据，表明该区域参与了反应选择和多重任务操作。例如，Filmer 等人（2013b）表明，通过对左 PFC 进行离线 tDCS，可以破坏年轻人中通常观察到的反应选择学习/训练增益。在这里，考虑到老年人大脑中与年龄相关的结构和功能变化的证据，我们评估了这种通过 tDCS 对左 PFC 进行的反应选择学习中断模式是否在老年人中观察到，测试该区域是否仍然是个体年龄增长时的关键反应选择节点。在一项针对 58 名老年人的预先注册研究中，我们对左、右 PFC 施加阳极、阴极和假刺激，并在参与者接受低和高反应选择负荷任务的训练过程中测量其表现。与我们之前的研究中的年轻参与者相比，积极刺激并没有破坏老年人的训练。研究结果强调了反应选择和学习所依赖的神经基质在年龄上的差异。
