Aperiodic Exponent as an EEG Marker of Interoceptive Attention during Gastric Fullness

Gastric interoceptive attention to internal, bodily signals such as hunger, satiety, and fullness are important for regulating feeding behaviors. However, abnormal processing or sensitivity to these can lead to disorders that result in overly restrictive or excessive consumption, highlighting the need for better understanding of the cortical processing of these cues. Specifically, understanding cortical representations of self-perceived gastric fullness have yet to be studied in humans. In this work, we demonstrate that consistently across individuals, the broadband power spectral density of EEG signals, as quantified by the aperiodic exponent, flattens after individuals drink water until fullness. Simultaneous measures of the stomach and heart demonstrate increased vagal drive to peripheral organs. We further find that changes in cortical aperiodic exponent patterns are associated with changes in the frequency of gastric oscillations. Overall, this suggests that the EEG aperiodic exponent may be a useful noninvasive biomarker for assessing gastric interoceptive attention.