Salivary Cortisol Measurement during Stress

Saliva samples for measurement of cortisol were collected at the 0 and 2 min time-points surrounding the stress or control test (stress condition: 4:42pm ± 0:16, 4:48pm ± 0:15; non-stress condition: 4:48pm ± 0:29, 4:53pm ± 0:29), as well as immediately before and after entering the scanner, i.e. at approximately 10 min and 1h15 min after stressor onset (stress condition: 4:53pm ± 0:16, 5:57pm ± 0:17; non-stress condition: 4:57pm ± 0:28, 5:59pm ± 0:29). This timing was designed to capture stressor-associated changes in cortisol, which have been shown to reach peak levels about 20 minutes following the SECPT [38 (link)]. The obtained saliva samples were centrifuged at 3000 rpm for 10–15 minutes and stored at -80°C, until required for assay. On the day of assay, salivary cortisol was determined using a high-sensitivity salivary cortisol enzyme immunoassay kit by Salimetrics, LLC (Carlsbad, CA). The intra-assay CV was 4.03%, and inter-assay CV was 6.19%.