Sleep Renormalizes Negative Emotional Generalization

Abstract

Overgeneralization of negative experiences co-occurs with sleep disruption and characterizes anxiety and posttraumatic stress disorder (PTSD). A strategically-designed behavioral paradigm tested whether sleep shifts emotional generalization away from negative and toward positive representations. Participants learned positive, negative, or neutral face-outcome associations, then completed immediate and delayed generalization testing with morphed faces after sleep or wakefulness. Sleep selectively enhanced positive generalization, whereas wakefulness favored negative generalization. To uncover the underlying neural mechanisms, individual variability in generalization was examined using fMRI and high-density EEG. Amygdala and limbic activity during outcome-processing predicted both stronger immediate negative generalization and a sleep-specific shift toward positive generalization. Additionally, sleep-spindle activity positively correlated with post-sleep increases in positive generalization and reductions in negative generalization. Together, these findings identify a neural mechanism through which sleep reduces negative bias while strengthening positive representations, highlighting a pathway by which sleep may protect against maladaptive generalization associated with anxiety and PTSD.