Neurophysiological excitation/inhibition imbalance in young adults burdened with childhood interpersonal trauma

Adverse childhood experiences, such as violence, abuse, and neglect, are increasingly recognized as significant modifiers of brain development. Here, we tested whether adults with histories of childhood trauma, but without psychiatric comorbidities exhibit altered excitation/inhibition (E/I) balance, as indicated by electroencephalography (EEG) signatures. Participants, divided into low-trauma and high-trauma groups, underwent two experimental conditions: eyes-closed resting-state recording and a reaction-time task with visual stimuli. From these data, we computed 1/f spectral slopes, a widely used electrophysiological marker of E/I balance; we complemented these analyses with a leaky integrate-and-fire (LIF) microcircuit model combined with a biophysically grounded forward-modeling approach to simulate realistic brain signals and derive E/I balance estimates. Group comparisons for both slopes and E/I estimates revealed significant resting-state differences in the posterior cortex, characterized by a shift toward increased neuronal excitation in the high-trauma group. Beyond these resting-state alterations, the high-trauma group exhibited altered stimulus-related dynamics in the frontal cortex relative to the pre-stimulus baseline, reflecting attenuated neuronal inhibition. E/I ratio measures were not significantly correlated with participants’ concurrent affective symptom levels, including state anxiety, trait anxiety, and depressive symptoms. Together, these findings suggest that childhood trauma is associated with alterations in cortical E/I balance that are not readily explained by present affective symptom burden and manifest across both resting and task-related brain dynamics.