Valence vs. Social Relevance: How the Amygdala and pSTS Process Emotional Expressions

According to Basic Emotion Theory (BET), emotions are pancultural discrete categories linked to distinct facial expressions and physiological states. In contrast, the Theory of Constructed Emotion (TCE) states that emotions are constructed through culture and fall along the dimensions of valence and arousal. Neural processing is quicker for expressions with negative valence (e.g. fear) than for positive expressions (e.g. happiness). Paradoxically, happy facial expressions are explicitly recognized faster than non-happy faces. To examine these processes, this thesis utilized multivariate pattern analysis (MVPA) to decode emotional expression (Happy vs. Fearful faces) and task instruction (categorizing Gender vs. Emotion) from neural patterns in the amygdala and posterior superior temporal sulcus (pSTS). H1: The amygdala, an epicenter of emotion, was hypothesized to exhibit higher decoding accuracy for emotional expression than the pSTS. H2: The pSTS, linked to higher-order social...Show moreAccording to Basic Emotion Theory (BET), emotions are pancultural discrete categories linked to distinct facial expressions and physiological states. In contrast, the Theory of Constructed Emotion (TCE) states that emotions are constructed through culture and fall along the dimensions of valence and arousal. Neural processing is quicker for expressions with negative valence (e.g. fear) than for positive expressions (e.g. happiness). Paradoxically, happy facial expressions are explicitly recognized faster than non-happy faces. To examine these processes, this thesis utilized multivariate pattern analysis (MVPA) to decode emotional expression (Happy vs. Fearful faces) and task instruction (categorizing Gender vs. Emotion) from neural patterns in the amygdala and posterior superior temporal sulcus (pSTS). H1: The amygdala, an epicenter of emotion, was hypothesized to exhibit higher decoding accuracy for emotional expression than the pSTS. H2: The pSTS, linked to higher-order social processing, was hypothesized to exhibit higher decoding accuracy for task instruction than the amygdala. For task instruction, the left amygdala exhibited significantly above-chance (50%) decoding accuracy, and the right pSTS showed significantly below-chance decoding. The findings did not support either hypothesis (H1 and H2). However, since the sample consisted of two participants (N = 2), the results are best interpreted as inconclusive. Should these findings be replicated in an adequate sample (N ≥ 30), they may have implications for understanding emotion theory (BET vs. TCE), as well as for disorders characterized by atypical social-emotional perception, such as autism spectrum disorder (ASD).Show less

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Valence vs. Social Relevance: How the Amygdala and pSTS Process Emotional Expressions