Updating Fearful Memories with Extinction Training during Reconsolidation: A Human Study Using Auditory Aversive Stimuli

Learning to fear danger in the environment is essential to survival, but dysregulation of the fear system is at the core of many anxiety disorders. As a consequence, a great interest has emerged in developing strategies for suppressing fear memories in maladaptive cases. Recent research has focused in the process of reconsolidation where memories become labile after being retrieved. In a behavioral manipulation, Schiller et al., (2010) reported that extinction training, administrated during memory reconsolidation, could erase fear responses. The implications of this study are crucial for the possible treatment of anxiety disorders without the administration of drugs. However, attempts to replicate this effect by other groups have been so far unsuccessful. We sought out to reproduce Schiller et al., (2010) findings in a different fear conditioning paradigm based on auditory aversive stimuli instead of electric shock. Following a within-subject design, participants were conditioned to two different sounds and skin conductance response (SCR) was recorded as a measure of fear. Our results demonstrated that only the conditioned stimulus that was reminded 10 minutes before extinction training did not reinstate a fear response after a reminder trial consisting of the presentation of the unconditioned stimuli. For the first time, we replicated Schiller et al., (2010) behavioral manipulation and extended it to an auditory fear conditioning paradigm

Fish oil and postoperative atrial fibrillation : the Omega-3 Fatty Acids for Prevention of Post-operative Atrial Fibrillation (OPERA) randomized trial

Context: Postoperative atrial fibrillation or flutter (AF) is one of the most common complications of cardiac surgery and significantly increases morbidity and health care utilization. A few small trials have evaluated whether long-chain n-3-polyunsaturated fatty acids (PUFAs) reduce postoperative AF, with mixed results. Objective: To determine whether perioperative n-3-PUFA supplementation reduces postoperative AF. Design, Setting, and Patients: The Omega-3 Fatty Acids for Prevention of Postoperative Atrial Fibrillation (OPERA) double-blind, placebo-controlled, randomized clinical trial. A total of 1516 patients scheduled for cardiac surgery in 28 centers in the United States, Italy, and Argentina were enrolled between August 2010 and June 2012. Inclusion criteria were broad; the main exclusions were regular use of fish oil or absence of sinus rhythm at enrollment. Intervention: Patients were randomized to receive fish oil (1-g capsules containing 65840 mg n-3-PUFAs as ethyl esters) or placebo, with preoperative loading of 10 g over 3 to 5 days (or 8 g over 2 days) followed postoperatively by 2 g/d until hospital discharge or postoperative day 10, whichever came first. Main Outcome Measure: Occurrence of postoperative AF lasting longer than 30 seconds. Secondary end points were postoperative AF lasting longer than 1 hour, resulting in symptoms, or treated with cardioversion; postoperative AF excluding atrial flutter; time to first postoperative AF; number of AF episodes per patient; hospital utilization; and major adverse cardiovascular events, 30-day mortality, bleeding, and other adverse events. Results: At enrollment, mean age was 64 (SD, 13) years; 72.2% of patients were men, and 51.8% had planned valvular surgery. The primary end point occurred in 233 (30.7%) patients assigned to placebo and 227 (30.0%) assigned to n-3-PUFAs (odds ratio, 0.96 [95% CI, 0.77-1.20]; P=.74). None of the secondary end points were significantly different between the placebo and fish oil groups, including postoperative AF that was sustained, symptomatic, or treated (231 [30.5%] vs 224 [29.6%], P=.70) or number of postoperative AF episodes per patient (1 episode: 156 [20.6%] vs 157 [20.7%]; 2 episodes: 59 [7.8%] vs 49 [6.5%]; 653 episodes: 18 [2.4%] vs 21 [2.8%]) (P=.73). Supplementation with n-3-PUFAs was generally well tolerated, with no evidence for increased risk of bleeding or serious adverse events. Conclusion: In this large multinational trial among patients undergoing cardiac surgery, perioperative supplementation with n-3-PUFAs, compared with placebo, did not reduce the risk of postoperative AF. Trial Registration: clinicaltrials.gov Identifier: NCT0097048