Wednesday, March 04, 2009

Erasing fear responses and preventing the return of fear.

Kindt et al. demonstrate an interesting effect of a beta-blocker that one thinks might become part of clinical practice soon. They found that a conditioned fear response can be weakened by disrupting the reconsolidation of the fear memory with propranolol and that this disruption prevents the return of fear. While Propranolol disrupts the reconsolidation of the fear memory, it does not disrupt declarative memory (recall of the facts of the fear inducing event). The abstract:
Animal studies have shown that fear memories can change when recalled, a process referred to as reconsolidation. We found that oral administration of the beta-adrenergic receptor antagonist propranolol before memory reactivation in humans erased the behavioral expression of the fear memory 24 h later and prevented the return of fear. Disrupting the reconsolidation of fear memory opens up new avenues for providing a long-term cure for patients with emotional disorders.
Some details:
The conditioned fear response was measured as potentiation of the eyeblink startle reflex to a loud noise (40 ms, 104 dB) by electromyography of the right orbicularis oculi muscle. Stronger startle responses to the loud noise during the fear-conditioned stimulus (CS1+) as compared with the control stimulus (CS2-) reflects the fearful state of the participant elicited by CS1+. Startle potentiation taps directly into the amygdala, and fear-conditioning procedures yield highly reliable and robust startle potentiation.

Figure. (click to enlarge) (af) Mean startle potentiation to the fear-conditioned stimulus (CS1), the control stimulus (CS2) and noise alone (NA) trials (left) and mean expectancy scores of the unconditioned stimulus to CS1 and CS2 trials (right) during acquisition (trial 1–8), extinction (trial 1–10) and test (trial 1–5) for the placebo (n = 20, a,b), propranolol reactivation (n = 20, c,d) and propranolol without reactivation (n = 20, e,f) group. CS1+ refers to the fear conditioned stimulus during acquisition, CS1- refers to the fear conditioned stimulus during extinction and test, CS1-R refers to the reactivation of the fear conditioned stimulus and CS2- refers to the control stimulus during all phases of the experiment. Error bars represent s.e.m.

1 comment:

  1. One of the biggest obstacles to practicing positive self-talk is the canned and programmed nature of positive self talk. But what people fail to consider is that if they are not using canned positive self talk, they are likely using canned negative self talk, programmed over years of living with beliefs passed to us by others. I teach clients how to manage their stress, anxiety and depression through accepting positive self talk, and practicing it until the positive thoughts come more easily than the negative thoughts. It takes time, persistence and repetition, but that's not surprising since
    that's how the old thoughts got into our heads in the first place.

    I'm a mental health therapist with a practice
    in downtown Portland. I teach my clients mindfulness-based stress reduction to help them realize greater quality of life and achieve higher business and career aspirations.