Mind the stimulation site: Enhancing and diminishing sentence comprehension with anodal tDCS

Abstract

In a previous sham-controlled study, we showed the feasibility of increasing language comprehension in healthy participants by applying anodal transcranial direct current stimulation (atDCS) over the left inferior frontal gyrus (LIFG). In the present work, we present a follow-up experiment targeting with atDCS the left inferior parietal cortex (LIPC) while participants performed the same comprehension task used in our previous experiment. Both neural sites are crucial hubs of Baddeley's model of verbal short-term memory (vSTM).AtDCS over LIPC decreased accuracy as compared to sham and LIFG stimulation, suggesting the involvement of these brain regions in sentence comprehension. Crucially, our results highlighted that applying tDCS over different hubs of the same neural network can lead to opposite behavioral results, with relevant implications from a clinical perspective.

Causal evidence for the involvement of Broca’s area in second language acquisition: A longitudinal HD-tDCS study

“…Experimentally, tDCS has robustly elicited a variety of behavioral responses. Some of the most commonly observed phenomena include the improvement of novel vocabulary acquisition (Fiori, Kunz, Kuhnke, Marangolo, & Hartwigsen, 2018; Kurmakaeva et al, 2021; Owusu & Burianová, 2020; Perikova et al, 2022), improvement in phonemic or semantic fluency (Cattaneo, Pisoni, & Papagno, 2011; Holland et al, 2011), and improvement of sentence comprehension (Giustolisi, Vergallito, Cecchetto, Varoli, & Romero Lauro, 2018; Johari, Riccardi, Malyutina, Modi, & Desai, 2021; Vergallito et al, 2020).…”