Time to Face Language: Embodied Mechanisms Underpin the Inception of Face-Related Meanings in the Human Brain

Abstract

In construing meaning, the brain recruits multimodal (conceptual) systems and embodied (modality-specific) mechanisms. Yet, no consensus exists on how crucial the latter are for the inception of semantic distinctions. To address this issue, we combined electroencephalographic (EEG) and intracranial EEG (iEEG) to examine when nouns denoting facial body parts (FBPs) and nonFBPs are discriminated in face-processing and multimodal networks. First, FBP words increased N170 amplitude (a hallmark of early facial processing). Second, they triggered fast (~100 ms) activity boosts within the face-processing network, alongside later (~275 ms) effects in multimodal circuits. Third, iEEG recordings from face-processing hubs allowed decoding ~80% of items before 200 ms, while classification based on multimodal-network activity only surpassed ~70% after 250 ms. Finally, EEG and iEEG connectivity between both networks proved greater in early (0–200 ms) than later (200–400 ms) windows. Collectively, our findings indicate that, at least for some lexico-semantic categories, meaning is construed through fast reenactments of modality-specific experience.

The Neural Blending of Words and Movement: Event-Related Potential Signatures of Semantic and Action Processes during Motor–Language Coupling

“…Moreover, it would be useful to assess whether the modulations observed during our present shallow-level task manifest similarly when explicit semantic processing is required-as observed in behavioral motor-language coupling experiments (Afonso et al, 2019). Finally, although the question addressed in this study pertained to the temporal dimension, future studies should aim to complement our approach with highspatial-resolution methods, as done in recent magnetoencephalography (García et al, 2019;Klepp et al, 2014Klepp et al, , 2015Klepp et al, , 2019 and intracranial (García et al, 2020;Ibáñez et al, 2013) EEG experiments. Whereas limb-neutral semantic integration during MaV processing (relative to nAVs) covers a ∼330to 440-msec window (light yellow), effectorspecific N400 effects (relative to nMaVs) extend from ∼380 to ∼440 msec (dark yellow).…”

“…Whereas behavioral experiments show that MaVs can induce involuntary grip force modulations shortly after presentation (Da Silva et al, 2018;Frak et al, 2010), these two variables typically yield null motor-language coupling effects in shallow-processing paradigms (García & Ibáñez, 2016a). However, several neuroscientific studies have shown that significant neural effects can be traced in embodied paradigms yielding no behavioral differences between conditions (García et al, 2020;Mollo et al, 2016;Klepp et al, 2014;Sato et al, 2008;Pulvermüller et al, 2001). As argued for other neurolinguistic phenomena (Dottori et al, 2020), this reminds us that a null effect on one dependent variable must not be taken to reflect a null effect of the independent variable at large.…”

“…Each block included the same stimuli but in different pseudorandomized sequences (no more than three stimuli from the same category appeared in succession, and real words linked by meaning or form were separated by at least three trials). As in previous research (García et al, 2020), this allowed maximizing signal-to-noise ratio while retaining a strict control of psycholinguistic variables across conditions. Participants had to decide, as fast and accurately as possible, whether the string constituted a real Spanish word or not by pressing the left arrow with the index finger or the right arrow with the middle finger of their right hand, respectively.…”

“…For all remaining participants, data were band-pass filtered during recording (0.1-100 Hz) and offline (0.5-40 Hz) to remove undesired frequency components. The latter cutoff (40 Hz) was based on gold-standard recommendations to maximize data quality and temporal precision (Cohen, 2014) and to favor comparability with ERP studies on motor responses (Gentili et al, 2018;Fabi & Leuthold, 2017;Kadosh et al, 2007), action-verb processing (Sokoliuk, Calzolari, & Cruse, 2019;Casado et al, 2018), and other embodied language categories (García et al, 2020;Daly et al, 2019;Gentsch, Sel, Marshall, & Schütz-Bosbach, 2019).…”

“…In line with reported procedures (Dottori et al, 2020;Fittipaldi et al, 2020;García et al, 2020;Vilas et al, 2019;Salamone et al, 2018), eye movements or blink artifacts were corrected with independent component analysis, and remaining artifacts were rejected offline from trials that contained voltage fluctuations exceeding ±200 μV. Bad channels were identified via visual inspection by two experts (S. C. and A. P.) following the exact same approach used by our team in previous EEG studies on semantic and motoric processes (Dottori et al, 2017(Dottori et al, , 2020Vilas et al, 2019;Yoris et al, 2017;García-Cordero et al, 2016;Melloni et al, 2015;Ibáñez et al, 2010Ibáñez et al, , 2013Aravena et al, 2010).…”