Shackman, A. J., Maxwell, J. S., McMenamin, B. W., Greischar, L. L. & Davidson, R. J. (2011). Stress potentiates early and attenuates late stages of visual processing. Journal of Neuroscience, 31, 1156-1161. PDFicon-25x39
Stress can fundamentally alter neural responses to incoming information. Recent research suggests that stress and anxiety shift the balance of attention away from a task-directed mode, governed by refrontal cortex, to a sensory-vigilance mode, governed by the amygdala and other threat-sensitive regions. A key untested prediction of this framework is that stress exerts dissociable effects on different stages of information processing.

This study exploited the temporal resolution afforded by event-related potentials to disentangle the impact of stress on vigilance, indexed by early perceptual activity, from its impact on task-directed cognition, indexed by later postperceptual activity in humans.

Results indicated that threat of shock amplified stress, measured using retrospective ratings and concurrentfacial electromyography. Stress also double-dissociated early sensory-specific processingfrom latertask-directed processing of emotionally neutral stimuli: stress amplified N1 (184 –236 ms) and attenuated P3 (316 – 488 ms) activity. This demonstrates that stress can have strikingly different consequences at different processing stages. Consistent with recent suggestions, stress amplified earlier extrastriate activity in a manner consistent with vigilance for threat (N1), but disrupted later activity associated with the evaluation of task-relevant information (P3).

These results provide a novel basis for understanding how stress can modulate information processing in everyday life and stress-sensitive disorders.