Trauma film viewing and intrusive memories: Relationship between salivary alpha amylase, endocannabinoids, and cortisol.

The endogenous cannabinoid (ECB) system is a small molecule lipid signalling system that is involved in stress response activation and is associated with PTSD, but it is unclear whether salivary ECBs are part of the sympathetic nervous system response to stress. We conducted an adapted trauma film paradigm, where participants completed a cold pressor test (or control) while watching a 10-minute trauma film. We also collected saliva and hair samples and tested them for ECBs, cortisol, and salivary alpha amylase (sAA).

Angry and fearful compared to happy or neutral faces as conditional stimuli in human fear conditioning: A systematic review and meta-analysis.

Some previous research has shown stronger acquisition and impaired extinction of fear conditioned to angry or fearful compared to happy or neutral face conditional stimuli (CS) - a difference attributed to biological 'preparedness'. A systematic review and meta-analysis of fear conditioning studies comparing face CSs of differing expressions identified thirty studies, eighteen of which were eligible for meta-analysis. Skin conductance responses were larger to angry or fearful faces compared to happy or neutral faces during habituation, acquisition and extinction.