Hemodynamic and electrophysiological studies indicate differential
brain response to emotionally arousing, compared to neutral,
pictures. The time course and source distribution of
electrocortical potentials in response to emotional stimuli,
using a high-density electrode (129-sensor) array were examined
here. Event-related potentials (ERPs) were recorded while
participants viewed pleasant, neutral, and unpleasant pictures.
ERP voltages were examined in six time intervals, roughly
corresponding to P1, N1, early P3, late P3 and a slow wave window.
Differential activity was found for emotional, compared to neutral,
pictures at both of the P3 intervals, as well as enhancement
of later posterior positivity. Source space projection was
performed using a minimum norm procedure that estimates the
source currents generating the extracranially measured electrical
gradient. Sources of slow wave modulation were located in occipital
and posterior parietal cortex, with a right-hemispheric dominance.