This Week in The Journal

doi:10.1523/JNEUROSCI.twij.43.26.2023

Ocular Movements Reflect Auditory Attentional Demand

Claudia Contadini-Wright, Kaho Magami, Nishchay Mehta, and Maria Chait

The effort required for listening in a noisy environment engages multiple brain networks, including attention and memory but also visual pathways. Pupil dilation (PD) has been established as a measure of auditory attention, as it is thought to reflect the arousal aspects of effort. This week, Contadini-Wright et al. identify a second way to use ocular signals to measure auditory attention: by measuring microsaccades (MSs), the tiny eye movements that keep our view in focus and are thought to reflect automatic visual exploratory sampling. Whereas PD reflects a state of arousal, here the researchers show that MSs were associated with the allocation of instantaneous attention. In the current study, adults with normal hearing were asked to identify the meaning of a sentence, “show the dog the [color] [number],” by selecting the correct colored number onscreen with a mouse. The sentence was presented under low-load and high-load conditions, with more or less background noise, and were presented in two experiments in either conventional order (with key words at the end) or in a “Yoda” format, with the key words presented first: “[color] [number] is show the dog where the.” As expected, PD increased in all conditions at sentence onset and decreased with sentence offset, but the increase was much larger in the high-load condition. The MS rate decreased under high-load conditions relative to low-load conditions, but whereas PD changes occurred throughout the listening period, the MS rate changes were more temporally distinct, reflecting the lowest MS rates at times when the demand on auditory attention was highest. The authors conclude that the results indicate that brain mechanisms that generate MS draw on the same attentional resource pool that manages selective auditory attention.