Localized task-invariant emotional valence encoding revealed by intracranial recordings

Area of Science:

• Neuroscience
• Cognitive Science
• Psychology

Background:

• Emotion perception relies on distinguishing between negative, positive, and neutral valence.
• Emotional valence is a fundamental concept that transcends specific stimuli.
• Identifying task-invariant neural encoding for emotional valence is crucial for understanding emotion processing.

Purpose of the Study:

• To identify neural encoding for task-invariant emotional valence.
• To determine if high-gamma responses (HGRs) to words can decode emotional valence from HGRs to facial expressions.
• To investigate the presence of task-independent emotional valence information in specific brain regions.

Main Methods:

• Intracranial electroencephalography (iEEG) was recorded from 14 individuals during two tasks: reading emotional words and viewing emotional facial expressions.
• Quadratic discriminant analysis was employed to differentiate between positive, negative, and neutral emotional valence conditions based on HGRs.
• A classifier was trained on one task and cross-validated within and between tasks to assess generalizability.

Main Results:

• Emotional valence was successfully decoded from HGRs in the left medial orbitofrontal cortex and middle temporal gyrus.
• Decoding accuracy was significant for both within-task and between-task classifiers.
• These findings indicate that HGRs in these regions contain task-independent emotional valence information.

Conclusions:

• The left medial orbitofrontal cortex and middle temporal gyrus exhibit neural signals that encode emotional valence independently of the task.
• These brain regions may play a critical role in processing a universal representation of emotional valence.
• The study provides evidence for a shared neural substrate for emotional valence across different sensory modalities and tasks.