# Cortical γ-oscillations implement basic language operations: Evidence from electroencephalography in anaphora during english filler-gap dependency processing

## TL;DR

This study shows that gamma brain waves help process complex language structures, particularly in resolving anaphora in English filler-gap sentences.

## Contribution

The paper provides evidence that gamma oscillations support referential relations in anaphora processing during complex syntactic dependencies.

## Key findings

- Gamma oscillations (30–50 Hz and 50–90 Hz) showed differences in power for Mod vs. Comp anaphora at gap sites.
- Mod-based anaphora showed distinct gamma power patterns at N1 and N2 stages compared to Comp-based anaphora.
- Gamma oscillations support syntax-constrained retrieval of referential elements in wh-dependencies.

## Abstract

Hypotheses about top-down structure building propose that gamma (>30Hz) oscillations support the creation of syntax-semantics objects, contrasting with slow-rhythm entrainment of gamma oscillations tracking semantic fitness in bottom-up chunking. In bi-clausal filler-gap dependencies, like which message regarding/about him did Frank/Diana say__ that Diana/Frank received__ unexpectedly?, wh-fillers link to gap__ sites. Although adjunct noun-phrase modifiers (Mods) like regarding him and noun complements (Comps) like about him have equal contextual fitness, in anaphoric dependencies Mods are biased toward discourse coreference and Comps toward syntactic binding enabled by wh-dependencies. Anaphora resolution across syntax and discourse has been tied to increased power in low- and high-gamma oscillations in retrieval and integration of referential elements. This predicts gamma-range event-related power differences (ERPDs) as anaphora processes for Comps vs. Mods interact with matrix- vs. embedded-clause antecedents at gap sites in embedded-clause wh-dependencies, as clause-edge gaps support Comp-enabled syntax-constrained retrieval of referential elements in binding and as thematic gaps support referential relations into the sentential interpretation. Using cluster-based nonparametric permutation tests, Mod- vs. Comp-based anaphora-linked ERPDs were examined within 30–50 Hz and 50–90 Hz in evoked activity at say__ and received__ in 23 right-handed English speakers to capture cell-assembly formation in the creation of referential relations for Mods vs. Comps in wh-filler re-representations. Gamma-power differences for Mods vs. Comps in N1 antecedent-pronoun match vs. N1 antecedent-pronoun mismatch/N2 antecedent-pronoun match arose 30–50 Hz and 50–60 Hz at say__, and 50–90 Hz at received__. Mod vs. Comp modulations of anaphora-linked gamma ERPDs at gap sites suggest that gamma oscillations implement referential relations in complex wh-dependencies.