Inflexibly Focused under Stress: Acute Psychosocial Stress Increases Shielding of Action Goals at the Expense of Reduced Cognitive Flexibility with Increasing Time Lag to the Stressor

摘要

Dynamically adjusting the right amount of goal shielding tonvarying situational demands is associated with the flexibility ofncognitive control, typically linked with pFC functioning. Althoughnstress hormones are found to also bind to prefrontal receptors,nthe link between stress and cognitive control remains elusive.nBased on that, we aimed at investigating effects of acute psychosocialnstress on dynamic control adjustments. Forty-eight healthynvolunteers were exposed to either a well-established stress inductionnprotocol (the Trier Social Stress Test, TSST) or a standardizedncontrol situation before a selective attention (Simon) taskninvolving response conflicts. The individual physiological stressnresponse was monitored by analyzing levels of free cortisol andnα-amylase activity in saliva samples showing that the TSST reliablyninduced an increase of endogenous stress hormone levels.nAcute stress did not inevitably impair cognitive functioning, however,nas stressed participants showed tonically increased goalnshielding (to reduce interference) at the expense of decreasedncognitive flexibility. Importantly, as a novel finding in humans,nstress effects on cognitive functions were not present immediatelynafter the stress experience but developed gradually over timenand, therefore, paralleled the time course of the hypothalamus–npituitary–adrenal (HPA) stress response. In addition, the total increasenof individual cortisol levels reflecting HPA activity, but notnthe total changes in α-amylase activity associated with sympatheticnactivity, was reversely related to the amount of cognitivenflexibility in the final block of testing. Our study provides evidencenfor a stress-induced time-dependent decrease of cognitive flexibilitynthat might be related to changes in cortisol levels. ■