Berti Stefan, Vossel Gerhard, Gamer Matthias
Department of Psychology, Johannes Gutenberg-University Mainz, Mainz, Germany.
Department of Psychology, University of Würzburg, Würzburg, Germany.
Front Psychol. 2017 Oct 17;8:1780. doi: 10.3389/fpsyg.2017.01780. eCollection 2017.
Automatic orienting to unexpected changes in the environment is a pre-requisite for adaptive behavior. One prominent mechanism of automatic attentional control is the Orienting Response (OR). Despite the fundamental significance of the OR in everyday life, only little is known about how the OR is affected by healthy aging. We tested this question in two age groups (19-38 and 55-72 years) and measured skin-conductance responses (SCRs) and event-related brain potentials (ERPs) to novels (i.e., short environmental sounds presented only once in the experiment; 10% of the trials) compared to standard sounds (600 Hz sinusoidal tones with 200 ms duration; 90% of the trials). Novel and standard stimuli were presented in four conditions differing in the inter-stimulus interval (ISI) with a mean ISI of either 10, 3, 1, or 0.5 s (blocked presentation). In both age groups, pronounced SCRs were elicited by novels in the 10 s ISI condition, suggesting the elicitation of stable ORs. These effects were accompanied by pronounced N1 and frontal P3 amplitudes in the ERP, suggesting that automatic novelty processing and orientation of attention are effective in both age groups. Furthermore, the SCR and ERP effects declined with decreasing ISI length. In addition, differences between the two groups were observable with the fastest presentation rates (i.e., 1 and 0.5 s ISI length). The most prominent difference was a shift of the peak of the frontal positivity from around 300 to 200 ms in the 19-38 years group while in the 55-72 years group the amplitude of the frontal P3 decreased linearly with decreasing ISI length. Taken together, this pattern of results does not suggest a general decline in processing efficacy with healthy aging. At least with very rare changes (here, the novels in the 10 s ISI condition) the OR is as effective in healthy older adults as in younger adults. With faster presentation rates, however, the efficacy of the OR decreases. This seems to result in a switch from novelty to deviant processing in younger adults, but less so in the group of older adults.
自动定向到环境中的意外变化是适应性行为的一个先决条件。自动注意力控制的一个突出机制是定向反应（OR）。尽管OR在日常生活中具有根本重要性，但对于健康衰老如何影响OR却知之甚少。我们在两个年龄组（19 - 38岁和55 - 72岁）中测试了这个问题，并测量了对新异刺激（即实验中仅呈现一次的短环境声音；占试验的10%）与标准声音（200毫秒时长的600赫兹正弦波音调；占试验的90%）的皮肤电反应（SCR）和事件相关脑电位（ERP）。新异刺激和标准刺激在四种不同刺激间隔（ISI）条件下呈现，平均ISI分别为10、3、1或0.5秒（分组呈现）。在两个年龄组中，10秒ISI条件下的新异刺激都引发了明显的SCR，表明引发了稳定的OR。这些效应伴随着ERP中明显的N1和额叶P3波幅，表明自动新异刺激加工和注意力定向在两个年龄组中都是有效的。此外，SCR和ERP效应随着ISI长度的缩短而下降。另外，在最快呈现速率（即1和0.5秒ISI长度）时，两组之间的差异是可观察到的。最显著的差异是19 - 38岁组中额叶正波峰值从约300毫秒左右偏移到200毫秒，而在55 - 72岁组中，额叶P3波幅随着ISI长度的缩短呈线性下降。总体而言，这种结果模式并不表明健康衰老会导致加工效能普遍下降。至少在非常罕见的变化情况下（这里是10秒ISI条件下的新异刺激），OR在健康老年人中与年轻人一样有效。然而，随着呈现速率加快（更快），OR的效能会降低。这似乎导致年轻人从新异刺激加工转向偏差刺激加工，但在老年人组中则不太明显。
