School of Psychology, University of Birmingham, Birmingham, B15 2TT, UK; Psychology Department, Clinical Psychology, University of Amsterdam, Amsterdam, 1018 WT, NL, UK.
Psychology Department, Clinical Psychology, University of Amsterdam, Amsterdam, 1018 WT, NL, UK.
Neuroimage. 2019 Nov 15;202:116098. doi: 10.1016/j.neuroimage.2019.116098. Epub 2019 Aug 12.
Illness is often accompanied by perceived cognitive sluggishness, a symptom that may stem from immune system activation. The current study used electroencephalography (EEG) to assess how inflammation affected three different distinct attentional processes: alerting, orienting and executive control. In a double-blinded placebo-controlled within-subjects design (20 healthy males, mean age = 24.5, SD = 3.4), Salmonella typhoid vaccination (0.025 mg; Typhim Vi, Sanofi Pasteur) was used to induce transient mild inflammation, while a saline injection served as a placebo-control. Participants completed the Attention Network Test with concurrent EEG recorded 6 h post-injection. Analyses focused on behavioral task performance and on modulation of oscillatory EEG activity in the alpha band (9-12 Hz) for alerting as well as orienting attention and frontal theta band (4-8 Hz) for executive control. Vaccination induced mild systemic inflammation, as assessed by interleukin-6 (IL-6) levels. While no behavioral task performance differences between the inflammation and placebo condition were evident, inflammation caused significant alterations to task-related brain activity. Specifically, inflammation produced greater cue-induced suppression of alpha power in the alerting aspect of attention and individual variation in the inflammatory response was significantly correlated with the degree of alpha power suppression. Notably, inflammation did not affect orienting (i.e., alpha lateralization) or executive control (i.e., frontal theta activity). These results reveal a unique neurophysiological sensitivity to acute mild inflammation of the neural network that underpins attentional alerting functions. Observed in the absence of performance decrements, these novel findings suggest that acute inflammation requires individuals to exert greater cognitive effort when preparing for a task in order to maintain adequate behavioral performance.
疾病常伴有认知迟钝的感觉，这一症状可能源于免疫系统的激活。本研究采用脑电图（EEG）评估炎症如何影响三种不同的注意力过程：警觉、定向和执行控制。在一项双盲安慰剂对照的被试内设计中（20 名健康男性，平均年龄为 24.5 岁，标准差为 3.4 岁），采用伤寒沙门氏菌疫苗（0.025mg；Typhim Vi，赛诺菲巴斯德）诱导短暂的轻度炎症，而盐水注射作为安慰剂对照。参与者在注射后 6 小时内完成注意力网络测试，并同步记录脑电图。分析重点关注行为任务表现以及警觉和定向注意力的 alpha 波段（9-12Hz）和执行控制的额 theta 波段（4-8Hz）的振荡 EEG 活动的调制。通过白细胞介素 6（IL-6）水平评估疫苗诱导的轻度全身炎症。虽然炎症和安慰剂条件下的行为任务表现没有差异，但炎症确实导致与任务相关的大脑活动发生显著改变。具体来说，炎症导致警觉注意力的提示诱导 alpha 功率抑制增加，且个体炎症反应的差异与 alpha 功率抑制程度显著相关。值得注意的是，炎症并未影响定向（即 alpha 侧化）或执行控制（即额 theta 活动）。这些结果揭示了神经网络对急性轻度炎症的独特神经生理敏感性，这是注意力警觉功能的基础。在没有表现下降的情况下观察到这些新发现表明，急性炎症要求个体在为任务做准备时付出更大的认知努力，以维持足够的行为表现。
