Seidel Eva-Maria, Pfabigan Daniela M, Hahn Andreas, Sladky Ronald, Grahl Arvina, Paul Katharina, Kraus Christoph, Küblböck Martin, Kranz Georg S, Hummer Allan, Lanzenberger Rupert, Windischberger Christian, Lamm Claus
Social, Cognitive and Affective Neuroscience Unit, Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Vienna, Austria.
Hum Brain Mapp. 2015 Feb;36(2):744-55. doi: 10.1002/hbm.22661. Epub 2014 Oct 16.
Anticipatory processes prepare the organism for upcoming experiences. The aim of this study was to investigate neural responses related to anticipation and processing of painful stimuli occurring with different levels of uncertainty.
Twenty-five participants (13 females) took part in an electroencephalography and functional magnetic resonance imaging (fMRI) experiment at separate times. A visual cue announced the occurrence of an electrical painful or nonpainful stimulus, delivered with certainty or uncertainty (50% chance), at some point during the following 15 s.
During the first 2 s of the anticipation phase, a strong effect of uncertainty was reflected in a pronounced frontal stimulus-preceding negativity (SPN) and increased fMRI activation in higher visual processing areas. In the last 2 s before stimulus delivery, we observed stimulus-specific preparatory processes indicated by a centroparietal SPN and posterior insula activation that was most pronounced for the certain pain condition. Uncertain anticipation was associated with attentional control processes. During stimulation, the results revealed that unexpected painful stimuli produced the strongest activation in the affective pain processing network and a more pronounced offset-P2.
Our results reflect that during early anticipation uncertainty is strongly associated with affective mechanisms and seems to be a more salient event compared to certain anticipation. During the last 2 s before stimulation, attentional control mechanisms are initiated related to the increased salience of uncertainty. Furthermore, stimulus-specific preparatory mechanisms during certain anticipation also shaped the response to stimulation, underlining the adaptive value of stimulus-targeted preparatory activity which is less likely when facing an uncertain event.
预期过程使机体为即将到来的经历做好准备。本研究旨在调查与不同不确定水平下疼痛刺激的预期和处理相关的神经反应。
25名参与者（13名女性）在不同时间参加了脑电图和功能磁共振成像（fMRI）实验。一个视觉提示表明在接下来的15秒内的某个时间会确定性地或不确定性地（50%的概率）施加一次电刺激，刺激可能是疼痛的或非疼痛的。
在预期阶段的前2秒，不确定性的强烈影响表现为明显的额叶刺激前负波（SPN）以及较高视觉处理区域fMRI激活增加。在刺激施加前的最后2秒，我们观察到由中央顶叶SPN和后岛叶激活所指示的刺激特异性准备过程，这在确定性疼痛条件下最为明显。不确定预期与注意力控制过程相关。在刺激期间，结果显示意外的疼痛刺激在情感性疼痛处理网络中产生最强激活以及更明显的偏移P2。
我们的结果表明，在早期预期期间，不确定性与情感机制密切相关，并且与确定性预期相比似乎是一个更突出的事件。在刺激前的最后2秒，与不确定性增加的显著性相关的注意力控制机制被启动。此外，确定性预期期间的刺激特异性准备机制也塑造了对刺激的反应，强调了针对刺激的准备活动的适应性价值，而面对不确定事件时这种价值较小。
