Intracranial recordings reveal high-frequency activity in the human temporal-parietal cortex supporting non-literal...

Area of Science:

• Neuroscience
• Cognitive Science
• Linguistics

Background:

• Non-literal language (sarcasm, metaphor) involves abstract meanings beyond literal interpretations.
• Neuroimaging studies link non-literal processing to frontal, parietal, and temporal brain regions.
• Neurophysiological underpinnings of non-literal language processing remain underexplored.

Purpose of the Study:

• Investigate intracranial electroencephalography (EEG) patterns during non-literal language processing.
• Examine neurophysiological correlates in the temporal-parietal junction (TPJ).
• Utilize invasive electrophysiological monitoring for high spatiotemporal resolution.

Main Methods:

• Recruited seven neurosurgical patients with invasive EEG monitoring.
• Recorded intracranial neural responses over the TPJ and surrounding areas.
• Patients listened to vignettes with literal or non-literal statements and responded to questions.

Main Results:

• Observed differential neurophysiological activity in low-gamma (30-70 Hz) and delta (1-4 Hz) bands for non-literal vs. literal statements.
• High-gamma band (>70 Hz) activity was more prominent at TPJ electrodes for non-literal processing.
• High-gamma activity was accompanied by delta-band modulation in half of the patients.

Conclusions:

• Low- and high-frequency electrophysiological activities in the TPJ are critical for non-literal language processing.
• Intracranial electrocorticography offers unique insights into localized TPJ brain dynamics during non-literal language comprehension.