Institute for Biomagnetism and Biosignalanalysis, University Hospital Munster, Munster, Germany.
PLoS One. 2011 Apr 5;6(4):e18009. doi: 10.1371/journal.pone.0018009.
Acute stress is a stereotypical, but multimodal response to a present or imminent challenge overcharging an organism. Among the different branches of this multimodal response, the consequences of glucocorticoid secretion have been extensively investigated, mostly in connection with long-term memory (LTM). However, stress responses comprise other endocrine signaling and altered neuronal activity wholly independent of pituitary regulation. To date, knowledge of the impact of such "paracorticoidal" stress responses on higher cognitive functions is scarce. We investigated the impact of an ecological stressor on the ability to direct selective attention using event-related potentials in humans. Based on research in rodents, we assumed that a stress-induced imbalance of catecholaminergic transmission would impair this ability.
METHODOLOGY/PRINCIPAL FINDINGS: The stressor consisted of a single cold pressor test. Auditory negative difference (Nd) and mismatch negativity (MMN) were recorded in a tonal dichotic listening task. A time series of such tasks confirmed an increased distractibility occurring 4-7 minutes after onset of the stressor as reflected by an attenuated Nd. Salivary cortisol began to rise 8-11 minutes after onset when no further modulations in the event-related potentials (ERP) occurred, thus precluding a causal relationship. This effect may be attributed to a stress-induced activation of mesofrontal dopaminergic projections. It may also be attributed to an activation of noradrenergic projections. Known characteristics of the modulation of ERP by different stress-related ligands were used for further disambiguation of causality. The conjuncture of an attenuated Nd and an increased MMN might be interpreted as indicating a dopaminergic influence. The selective effect on the late portion of the Nd provides another tentative clue for this.
CONCLUSIONS/SIGNIFICANCE: Prior studies have deliberately tracked the adrenocortical influence on cognition, as it has proven most influential with respect to LTM. However, current cortisol-optimized study designs would have failed to detect the present findings regarding attention.
急性应激是一种对当前或即将到来的挑战的典型、多模式反应，会使生物体过度负荷。在这种多模式反应的不同分支中，糖皮质激素分泌的后果已经被广泛研究，主要与长期记忆（LTM）有关。然而，应激反应还包括其他内分泌信号和完全独立于垂体调节的神经元活动的改变。迄今为止，关于这种“皮质旁”应激反应对更高认知功能的影响的知识还很匮乏。我们使用人类事件相关电位研究了生态应激源对选择性注意能力的影响。基于啮齿动物的研究，我们假设应激引起的儿茶酚胺能传递不平衡会损害这种能力。
方法/主要发现：应激源由单次冷加压试验组成。在音对听任务中记录听觉负差（Nd）和失匹配负波（MMN）。一系列此类任务证实，在应激源开始后 4-7 分钟，注意力分散增加，表现为 Nd 减弱。唾液皮质醇在应激源开始后 8-11 分钟开始上升，此时事件相关电位（ERP）没有进一步的调制，因此排除了因果关系。这种效应可能归因于应激引起的中脑-额叶多巴胺能投射的激活。它也可能归因于去甲肾上腺素能投射的激活。不同应激相关配体对 ERP 调制的已知特征被用于进一步阐明因果关系。Nd 减弱和 MMN 增加的结合可以解释为多巴胺能的影响。Nd 晚期部分的选择性影响为此提供了另一个初步线索。
结论/意义：先前的研究一直跟踪研究了肾上腺皮质激素对认知的影响，因为它对 LTM 的影响最大。然而，目前的皮质醇优化研究设计将无法检测到关于注意力的现有发现。
