Multiple visual attention mechanisms are active already in infancy, most notably one supporting orienting towards stimuli and another, maintaining appropriate levels of alertness, when exploring the environment. They are thought to depend on separate brain networks, but their effects are difficult to isolate in existing behavioural paradigms. Better understanding of the contribution of each network to individual differences in visual orienting may help to explain their role in attention development. Here, we tested whether alerting and spatial cues differentially modulate pupil dilation in 8-month-old infants in a visual orienting paradigm. We found differential effects in the time course of these responses depending on the cue type. Moreover, using Principal Component Analysis (PCA) we identified two main components of pupillary response, which may reflect the alerting and orienting network activity. In a regression analysis, these components together explained nearly 40 % of variance in saccadic latencies in the spatial cueing condition of the task. These results likely demonstrate that both networks work together in 8-month-old infants and that their activity can be indexed with pupil dilation combined with PCA, but not with raw changes in pupil diameter.

多种视觉注意机制在婴儿期就已经活跃起来，最显着的是一种支持对刺激的定向，另一种在探索环境时保持适当的警觉水平。人们认为它们依赖于单独的大脑网络，但它们的影响很难在现有的行为范式中分离出来。更好地理解每个网络对视觉定向个体差异的贡献可能有助于解释它们在注意力发展中的作用。在这里，我们在视觉定向范式中测试了警报和空间线索是否差异调节 8 个月大婴儿的瞳孔扩张。我们发现，根据提示类型，这些反应的时间过程会产生不同的影响。此外，使用主成分分析（PCA），我们确定了瞳孔反应的两个主要组成部分，这可能反映了警报和定向网络活动。在回归分析中，这些组件共同解释了任务空间提示条件下扫视延迟近 40% 的方差。这些结果可能表明，这两个网络在 8 个月大的婴儿中协同工作，并且它们的活动可以通过瞳孔扩张结合 PCA 来索引，但不能通过瞳孔直径的原始变化来索引。