Search

Language comprehension must require some degree of attentional focus, but how do periods of inattention and/or split attention impact how language is processed? Here EEG was recorded while participants listened to full-length stories, and were periodically asked about whether they were fully attentive, were completely inattentive, or felt that they were in a split attention state. The ERP response to the words immediately preceding these attention questions was examined as a function of participant response, which allowed for the comparison of word processing in each of these attentional states. When participants were on-task, typical N400 effects of lexical frequency (smaller N400 for common compared to less common words), word position (smaller N400 for words appearing late in a sentence compared to words appearing with less preceding context), and surprisal (smaller N400 for relatively expected words compared to relatively unexpected words) were observed. When participants were in a fully inattentive state, the word-level effect of frequency was intact, but the context-dependent effects of word position and surprisal were significantly reduced. Interestingly, the pattern of results when participants were in a split attention state closely matched that of the fully inattentive state. Overall, the results demonstrate how attentional state influences sensitivity to language context during comprehension, and show that the consequences of inattention and split attention on word processing in context are quite similar, at least on the indices measured here.

This study examined the effects of stimulation targeting dorsolateral prefrontal cortex (DLPFC) on behavioral and neural oscillatory markers of proactive cognitive control in healthy adults. We hypothesized that active stimulation targeting the DLPFC would enhance proactive control compared to sham, leading to changes in the pattern of error rates and gamma-band power on the Dot Pattern Expectancy (DPX) task. We recorded EEG while participants completed the DPX, after receiving either 20 minutes of active DLPFC stimulation at 2 mA or sham stimulation in a counterbalanced within-participants design. The results showed significant tDCS-induced changes in the pattern of error rates on the DPX task indicative of enhanced proactive control, as well as predicted increases in gamma power associated with the engagement of proactive control. These results provide support for the role of DLPFC-mediated gamma activity in proactive cognitive control, and further, indicate that proactive control can be enhanced with non-invasive neurostimulation.