Treatment with a heat-killed preparation of Mycobacterium vaccae after fear conditioning enhances fear extinction in the fear-potentiated startle paradigm

Publication date: Available online 5 June 2019Source: Brain, Behavior, and ImmunityAuthor(s): James E. Hassell, James H. Fox, Mathew R. Arnold, Philip H. Siebler, Margaret W. Lieb, Dominic Schmidt, Emma J. Spratt, Tessa M. Smith, Kadi T. Nguyen, Chloé A. Gates, Kaley S. Holmes, K'loni S. Schnabel, Kelsey M. Loupy, Maike Erber, Christopher A. LowryAbstractThe hygiene hypothesis or “Old Friends” hypothesis proposes that inflammatory diseases are increasing in modern urban societies, due in part to reduced exposure to microorganisms that drive immunoregulatory circuits and a failure to terminate inappropriate inflammatory responses. Inappropriate inflammation is also emerging as a risk factor for anxiety disorders, affective disorders, and trauma-and stressor-related disorders, including posttraumatic stress disorder (PTSD), which is characterized as persistent re-experiencing of the trauma after a traumatic experience. Traumatic experiences can lead to long-lasting fear memories and fear potentiation of the acoustic startle reflex. The acoustic startle reflex is an ethologically relevant reflex and can be potentiated in both humans and rats through Pavlovian conditioning. Mycobacterium vaccae is a soil-derived bacterium with immunoregulatory and anti-inflammatory properties that has demonstrated to enhance fear extinction in the fear potentiated startle paradigm when given prior to fear conditioning. To determine if immunization with M. vaccae after fea...
Source: Brain, Behavior, and Immunity - Category: Neurology Source Type: research