Auditory cortical alpha desynchronization prioritizes the representation of memory items during a retention period

Abstract

Maintaining information in working memory normally happens in dynamic environments, with a multitude of distracting events. This is particularly evident in the auditory system, for example, when trying to memorize a telephone number during ongoing background noise. How relevant to-be-memorized information is protected against the adverse influence of a temporally predictable distractor was the main goal of the present study. For this purpose we adapted a Sternberg task variant established in the visual modality, with either a strong or a weak distracting sound presented at a fixed time during the retention period. Our behavioral analysis confirmed a small, albeit significant deterioration of memory performance in the strong distractor condition. We used a time-generalized decoding approach applied to magnetoencephalography (MEG) data to investigate the extent of memory probe-related information prior to the anticipated distractor onset and found a relative decrease for the strong distractor condition. This effect was paralleled by a predistractor alpha power decrease in the left superior temporal gyrus (STG), a cortical region putatively holding memory content relevant information. Based on gating frameworks of alpha oscillations, these results could be interpreted as a failed inhibition of an anticipated strong (more salient) distractor. However, in a critical analysis we found that reduced alpha power in the left STG was associated with relatively increased memory probe-related information. Our results therefore support the view of alpha power reductions in relevant sensory (here auditory) cortical areas to be a mechanism by which to-be-remembered information is prioritized during working memory retention periods.Auditory cortical alpha prioritizes to-be-memorized information

Degradation levels of continuous speech affect neural speech tracking and alpha power differently

“…This interpretation integrates well with the frameworks on alpha oscillations in the context of working memory as proposed, for example, by van Ede (2018), but also for auditory perception by Griffiths et al. (2019), and for auditory memory by Kraft, Demarchi, and Weisz (2019). Van Ede (2018) puts the idea forward that alpha power increases for tasks with sensory disengagement, while it decreases for tasks, which recruit the sensory representation.…”

Degradation levels of continuous speech affect neural speech tracking and alpha power differently

“…reflected in the ability to track specific features) up to a specific (breaking) point, when speech becomes too degraded so that no veridical information is activated. This interpretation integrates well with the frameworks on alpha oscillations in the context of working memory as proposed for example by van Ede (2018) (2018), but also for auditory perception by Griffith et al (2019), and for auditory memory by Kraft et al (2019). Van Ede puts the idea forward that alpha power increases for tasks with sensory disengagement, while it decreases for tasks which recruit the sensory representation.…”