Mobile electroencephalography (EEG) is a very useful tool to investigate the physiological
basis of cognition under real-world conditions. However, as we move experimentation
into less-constrained environments, the influence of state changes increases. The
influence of stress on cortical activity and cognition is an important example. Monitoring
of modulation of cortical activity by EEG measurements is a promising tool for assessing
acute stress. In this study, we test this hypothesis and combine EEG with independent
component analysis and source localization to identify cortical differences between a
control condition and a stressful condition. Subjects performed a stationary shooting
task using an airsoft rifle with and without the threat of an experimenter firing a
different airsoft rifle in their direction. We observed significantly higher skin conductance
responses and salivary cortisol levels (p < 0.05 for both) during the stressful conditions,
indicating that we had successfully induced an adequate level of acute stress. We
located independent components in five regions throughout the cortex, most notably in
the dorsolateral prefrontal cortex, a region previously shown to be affected by increased
levels of stress. This area showed a significant decrease in spectral power in the theta
and alpha bands less than a second after the subjects pulled the trigger. Overall, our
results suggest that EEG with independent component analysis and source localization
has the potential of monitoring acute stress in real-world environments