Slade, Kate and Pepper, Jessica and Oosterhuis, Elise and Herrmann, Björn and Johnsrude, Ingrid and Nuttall, Helen E (2025) Entraining alpha oscillations to facilitate auditory working memory: A TMS-EEG study. In: International Symposium on Hearing 2025, 2025-06-01 - 2025-06-06. (Unpublished)
Full text not available from this repository.Abstract
ABSTRACT. Neural alpha oscillations may support working memory during speech perception. Specifically, alpha oscillations in parietal cortex may promote inhibition of distracting sounds, whereas alpha oscillations in temporal cortex may enhance attention to target sounds. Importantly, alpha activity during speech perception may be different for younger and older adults. We hypothesised that entraining alpha activity in parietal and temporal cortex may facilitate speech perception. We investigated whether TMS delivered at an individualised alpha frequency (alpha-TMS) benefits auditory working memory, and how this may be affected by age. Sixty-four participants: 32 younger adults (M age = 20.78) and 32 older adults (M age = 68.38), completed trials of an auditory working memory task. Participants attended to and recalled 9-digit sequences, whilst ignoring irrelevant sentences. Before the to-be-ignored sentences, participants received alpha-TMS. We investigated the effects of 1) distractibility of irrelevant sentences (less vs. more distracting); 2) site of alpha-TMS (vertex vs. parietal vs. temporal); 3) age group (younger vs. older), on digit recall and alpha power in auditory and parietal regions. For digit recall, we observed that across all alpha-TMS conditions and age groups, digit recall was significantly reduced in trials with more distracting to-be-ignored sentences. For alpha power, recorded from both the temporal regions and parietal regions, there was a significant main effect of TMS location. This effect showed that alpha power recorded from auditory regions was significantly increased when alpha-TMS was delivered to temporal cortex, compared to alpha-TMS delivered to the vertex (control) and parietal cortex. Similarly, alpha power recorded from parietal regions was significantly increased when alpha-TMS was delivered to the parietal site, compared to alpha-TMS delivered to the vertex and temporal sites. Further, older adults displayed significantly higher alpha power, recorded from both auditory and parietal cortex, across all experimental conditions. Interestingly, the strength of parietal alpha power after parietal alpha-TMS, was significantly higher in trials with more distracting to-be-ignored sentences compared to less distracting sentences in older adults. These data indicate that alpha-TMS can modulate parietal and auditory alpha power, which may influence inhibitory and attentional processes during auditory perception, which may be further modulated by age. However, effects were not reflected in behavioural performance. It is possible that age-related declines in auditory working memory were compensated for by TMS-modulated alpha power.