Measuring task-evoked pupillary (TEP) responses as an index of phasic activity in the locus coeruleus (LC), we examined two competing hypotheses regarding the alerting and orienting mechanisms of attention. According to a dual mechanism account (Fernandez-Duque & Posner, 1997), two separate noradrenergic and cholinergic mechanisms modulate, respectively, the alerting and orienting effects. However, Corbetta and colleagues (2008) proposed that LC phasic activity may also be involved in orienting effect through its functional relationship with the ventral attentional network. We recruited seventy-five healthy Norwegian participants to perform a Posner cueing task. Both behavioral and pupillary responses revealed the alerting effect. Also, both behavioral and pupillary responses indicated that cued attention is affected by age. Behavioral responses also revealed orienting effect However, we found no TEP differences between valid, invalid, and neutral conditions, suggesting that TEP effects were driven by the alerting effect of cue presentation. Moreover, both behavioral and pupillary estimates of alertness and orienting were uncorrelated. Finally, individual differences in general cognitive abilities did not appear to affect the orienting and alerting mechanisms. This pattern of results is consistent with the dual mechanism account of attention. However, the LC involvement in the (re)orienting attention may be driven by state-specific factors.

通过测量任务诱发的瞳孔（TEP）反应，作为蓝斑轨迹（LC）阶段性活动的指标，我们研究了关于注意力的警觉和定向机制的两个相互竞争的假设。根据双重机制的解释（Fernandez-Duque＆Posner，1997），两个独立的去甲肾上腺素能和胆碱能机制分别调节着戒备和定向。效果。但是，Corbetta及其同事（2008年）提出，LC的相活动可能还通过其与腹侧注意网络的功能关系参与了定向作用。我们招募了75名健康的挪威参与者来执行Posner提示任务。行为和瞳孔反应都显示出警觉作用。同样，行为和瞳孔反应都表明提示的注意力受到年龄的影响。行为反应也显示定向效应。但是，我们发现有效，无效和中性条件之间没有TEP差异，这表明TEP效应是由提示提示的警报效应驱动的。此外，机敏性和定向的行为和瞳孔估计均不相关。最后，一般认知能力的个体差异似乎并未影响定向和警报机制。这种结果模式与关注的双重机制是一致的。但是，LC在（重新）定向注意中的参与可能是由特定于国家的因素驱动的。