Behavioral and Event-Related Potential Study of Emotion Concept Activation in Young Adults with High Versus Low Alexithymia Traits

<b>Background</b>: Although alexithymia is characterized by difficulties in emotional processing, the underlying mechanisms remain uncertain. We hypothesized that specific deficits in activating and using emotion concepts would be associated with impairments in higher-order emotional processing in individuals with high levels of alexithymia. <b>Methods</b>: To elucidate these mechanisms, 20 high-alexithymia and 17 low-alexithymia young adults (M_age = 18.38, SD_age = 0.77), identified according to the Toronto Alexithymia Scale-20, were included in this study to examine distinct neural and behavioral features between participants with different levels of alexithymia. Participants selected target facial expressions primed by emotion concepts from interferential faces while their event-related potentials (ERPs) were recorded. We modulated the clarity of emotion concepts and varied the relative working-memory load of the emotion concepts versus facial features to promote top-down or bottom-up processing. <b>Results</b>: Behaviorally, clear emotion concepts facilitated accurate target identification in both groups. Event-related potential results show that the high alexithymia group had reduced N400 amplitudes than the low-alexithymia group in the top-down domain processing condition (mean difference of 2.75 μV, 95% CI [0.40, 5.11], <i>Cohen's d</i> = 0.54), indicating reduced cognitive resource allocation for deliberately activating emotion concepts. <b>Conclusions</b>: These findings suggest that individuals with high alexithymia have emotion deficits, potentially due to difficulty in the deliberate activation of emotion concepts. Our findings provide theoretical and clinical implications for affective science by highlighting a possible conceptual-processing mechanism through which alexithymia may be linked to the development and persistence of comorbid affective symptoms.