Gamma EEG activity induced by semantic violation during sentence reading

Area of Science:

• Neuroscience
• Psycholinguistics
• Cognitive Science

Background:

• Understanding sentence processing is crucial for cognitive neuroscience.
• Electroencephalography (EEG) offers insights into neural dynamics during language comprehension.
• The role of gamma band oscillations in semantic processing remains an active area of research.

Purpose of the Study:

• To investigate changes in electroencephalographic (EEG) power spectrum related to semantic violations in Italian sentences.
• To explore the specific frequency bands and scalp topographies associated with semantic anomaly detection.
• To evaluate the utility of gamma band activity as a tool for studying linguistic network dynamics.

Main Methods:

• Participants listened to Italian sentences, some containing semantic violations.
• EEG data was recorded and analyzed for power spectrum changes, focusing on the gamma frequency range (30-100 Hz).
• Analyses examined differences in gamma band activity between correct and incorrect sentences, considering specific frequency sub-bands and scalp locations.

Main Results:

• Significant differences in gamma band activity were observed between well-formed and semantically violated sentences.
• Lower gamma band (30-45 Hz) changes at the target word indicated violations without specific scalp topography.
• Upper gamma bands (55-75 Hz and 75-100 Hz) showed greater activity for correct sentences following the violation, localized to anterior right scalp sites.

Conclusions:

• Gamma band oscillations, particularly in upper ranges, are sensitive to semantic violations during sentence processing.
• The anterior right scalp region may play a specific role in processing semantic anomalies, as indicated by gamma activity.
• Gamma band analysis provides a valuable complementary tool to evoked potentials for investigating neural dynamics in language comprehension.