Age differences in peritraumatic and posttraumatic processing.

There is limited research investigating the mechanisms underlying the lower rate of posttraumatic stress disorder (PTSD) in older compared to younger adults. This study examined age differences in peritraumatic and posttraumatic reactions, and the use of two emotion regulation strategies (rumination and positive reappraisal) using a trauma film induction paradigm. Participants (45 older adults and 45 younger adults) watched a trauma film. Eye gaze, Galvanic Skin Response, peritraumatic distress, and emotion regulation were assessed during the film. Participants completed an intrusive memory diary over the next 7 days and follow-up measures of posttraumatic symptoms and emotion regulation. Findings showed no age differences in peritraumatic distress or use of rumination or positive reappraisal during film viewing. Older adults reported lower posttraumatic stress and distress from intrusive memories than younger adults at the 1-week follow-up, despite experiencing a comparable number of intrusions. Rumination was a unique predictor of intrusive and hyperarousal symptoms, after accounting for age. There were no age differences in the use of positive appraisal, and positive reappraisal was not associated with posttraumatic stress. Lower rates of late-life PTSD may relate to decreased use of maladaptive emotion regulation (i.e., rumination), rather than increased use of adaptive emotion regulation strategies (i.e., positive reappraisal). (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Differential effects of GABAA receptor activation in the prelimbic and orbitofrontal cortices on anxiety.

RATIONALE: The development of effective anxiety treatments has been hindered by limited understanding of the neurobiological mechanisms involved in anxiety regulation. Whilst gamma-aminobutyric acid (GABA) neurotransmission in the prefrontal cortex (PFC) is one mechanism consistently implicated in anxiety regulation, PFC subregions may contribute uniquely. OBJECTIVES: The present study examined the effects of inactivating the PFC subregions of the prelimbic cortex (PrL) or orbitofrontal cortex (OFC) through GABAA receptor (GABAAR) activation, on anxiety behaviours in male Wistar rats. METHODS: Sixty-six male Wistar rats were surgically implanted with bilateral cannulae into the PrL (n = 33) or the OFC (n = 33). Rats then received a microinjection of either the GABAA receptor agonist muscimol or vehicle prior to each experiment, conducted 1 week apart. Measures of anxiety were examined using the elevated plus maze (EPM) and the emergence test (ET). The effect on locomotor activity (baseline or methamphetamine-induced) was also tested. RESULTS: Differential effects of brain region inactivation on anxiety-like behaviour were shown by measures in the EPM and ET; muscimol infused into the PrL-reduced anxiety-like behaviour, yet had no significant effect when infused into the OFC, compared with control treated rats. No effects on locomotor activity at baseline or following methamphetamine treatment were found. CONCLUSIONS: This study highlights that activation of GABAARs specifically within the PrL, but not OFC, reduces anxiety behaviours in male rats. This suggests that activity of the PrL plays a more important role than the OFC in the neurobiological mechanisms of unconditioned anxiety and should be targeted for future therapies.