Possiamo cancellare i brutti ricordi ?
A presto una nuova promettente terapia medica per il Disturbo post traumatico da Stress, come si evince da una ricerca pubblicata online ad ottobre su Biological Psychiatry, ancora in attesa di essere pubblicata.
Oxytocin Facilitates the Extinction of Conditioned Fear in Humans
Monika Eckstein, Benjamin Becker, Dirk Scheele, Claudia Scholz, Katrin Preckel, Thomas E. Schlaepfer, Valery Grinevich, Keith M. Kendrick, Wolfgang Maier, René Hurlemann.
Abstract
Current neurocircuitry models of anxiety disorders posit a lack of inhibitory tone in the amygdala during acquisition of Pavlovian fear responses and deficient encoding of extinction responses in amygdala-medial prefrontal cortex mPFC circuits. Competition between these two responses often results in a return of fear, thus limiting control over anxiety. However, one intriguing hypothesis holds that a pharmacological strategy aimed at reducing amygdala activity while simultaneously augmenting mPFC function could facilitate the extinction of conditioned fear.MethodsKey among the endogenous inhibitors of amygdala activity in response to social fear signals is the hypothalamic peptide oxytocin. To address the question whether oxytocin can strengthen Pavlovian extinction beyond its role in controlling social fear, we conducted a functional magnetic resonance imaging fMRI experiment involving 62 healthy male participants in a randomized, double-blind, parallel group, placebo-controlled design. Specifically, subjects were exposed to a Pavlovian fear conditioning paradigm before receiving a intranasal dose 24 IU of synthetic oxytocin or placebo.ResultsWe found that oxytocin, when administered intranasally after Pavlovian fear conditioning, increases electrodermal responses and PFC signals to conditioned fear in the early phase of extinction and enhances the decline of skin conductance responses in the late phase of extinction. Furthermore, oxytocin evokes an unspecific inhibition of amygdalar responses in both phases.ConclusionsCollectively, our findings identify oxytocin as a differentially acting modulator of neural hubs involved in Pavlovian extinction. This specific profile of oxytocin action may open up new avenues for enhancing extinction-based therapies for anxiety disorders.
