Emotion arousal but not valence is strongly represented in aperiodic EEG activity stemming from thalamocortical interactions

Oscillatory EEG signals contain both periodic and aperiodic (1/f components), segregating which is important for gaining insights into the underlying neural computations. Several studies have explored the periodic features underlying neural basis of emotion processing, while 1/f component is less explored. Hence, the present study sought to determine whether seeing emotionally laden music video clips have an impact on aperiodic components along with the periodic components and their underlying basis by conceptualizing a biophysically realistic computational model. Using the publicly available Data for Emotional Analysis using Physiological Signals (DEAP) dataset we elucidate that there is a significant increase in exponent and offset of aperiodic background during high arousal compared to low arousal trials. In contrast, there were no discernible variations between the aperiodic components during the high and low valence categories. In high arousal, we also discovered reduction in alpha power in line with previous studies. Finally, to elucidate the underlying mechanisms, we employed a biophysically realistic and previously established thalamo-cortical model of neural field activity, which which allowed us to characterize that heightened emotional arousal appears emerge from an increased cooperation in information communication between neuronal populations in reticular and relay nuclei of thalamus. Significance statementDissociation of emotion and valence and arousal is an established theory in affective neuroscience. Are these dimensions represented in aperiodic background of macrocscopic electrophysiological scales of EEG? We sought to ask this question in the publicly available DEAP data. Our findings of increased aperiodic components during high arousal in contrast to low arousal suggest heightened neural activity alongside an inhibitory influence. Using a neural field model of thalamo-cortical interactions reveals a mechanistic approach that suggests heightened arousal corresponds to an enhanced inhibitory coupling between thalamic reticular and relay neuronal populations. In essence, this study advances our understanding of the intricate relationship between electrophysiological signals and emotion dimensions, shedding light on the mechanisms underlying arousal-related emotional responses.