Cortical and cardiovascular responses to acute stressors and their relations with psychological distress.

The purpose of this study was to assess the interrelation between cortical, cardiovascular, behavioural, and psychological responses to acute stressors in a large sample of healthy individuals. To date, there are only preliminary evidences for a significant association among these psychophysiological indexes during a stress task. 65 participants completed psychological questionnaires (Beck Depression Inventory and State-Trait Anxiety Inventory) and underwent a psychosocial math stress task, consisting of a control and an experimental (i.e. stressful) condition. Prefrontal and autonomic activities were recorded using respectively a 2-channel near-infrared spectroscopy (NIRS) device and a portable ECG monitoring system. Results evidenced an increased activation of both frontal areas assessed by NIRS, and a positive association between the right NIRS channel and heart rate changes from baseline, during both control and experimental conditions. Subjective stress increased during the procedure, reaching its maximum during the experimental condition. Behavioural performances during the task (e.g. response time) did not correlate with anxiety or depression. Autonomic data evidenced, as expected, an overall reduction of vagal tone during the experimental condition. Finally, severity of depressive and anxious symptoms predicted an increase in parasympathetic activity both at rest and during the task, even when controlling for respiration rate. Results support the hypothesis of an integration between right sectors of frontopolar or dorsolateral PFC and cardiac regulation. Trait anxiety and depression predicted an increase in vagal tone during the entire procedure. The implication of these findings is discussed.