Netcontrol rat1/13/2024 Other animal models focus on modelling specific neurobiological sequelae or specific behavioural findings reported in PTSD. However, it is not entirely clear what constitutes such an event in rodents. Moreover, rodents show differential vulnerability to the lasting effects of predator scent stress (Bush et al., 2007 Cohen et al., 2003, 2004, 2005, 2006a–d, 2007a, b, 2008 Cohen and Zohar, 2004 Kozlovsky et al., 2007a, b Matar et al., 2006 Mazor et al., 2007). focus on the aspect of a traumatic experience as a life-threatening event (Adamec et al., 2006a, b, 2007 Apfelbach et al., 2005 Blanchard et al., 2003 Blanchard and Blanchard, 1990 Blundell et al., 2005 Cohen et al., 1996, 1999, 2000, 2007a, 2008 Diamond et al., 2006 Endres et al., 2005 File et al., 1993 Kozlovsky et al., 2007a, b Matar et al., 2006 Mazor et al., 2007 Richter-Levin, 1998 Roseboom et al., 2007 Sullivan and Gratton, 1998 Takahashi et al., 2005 Wang et al., 2000). Animal ‘trauma’ includes models that address the intensity of the trauma and models concerned with its ethological relevance, e.g. Hence, there is no consensus as to whether the development of such a model should begin from replicating the trauma, replicating the neurobiological and behavioural characteristics or focusing on the presumed mechanisms. However, no single widely accepted animal model of PTSD has been established to date, and there is an ongoing debate over what constitutes a valid animal model for this disorder. Deficient embedding or contextualization of the traumatic events in autobiographical memory is thought to be one of the main problems in PTSD (Ehlers and Clark, 2000).ĭevelopment of a valid animal model is an important step in elucidating neural mechanisms underlying PTSD ultimately, the ‘optimal’ animal model should incorporate trauma-like exposure, will mimic pathophysiological and behavioural findings present in PTSD and will presumably involve neurobiological mechanisms that participate in PTSD pathophysiology. For example, for a combat veteran, the sound of a passing helicopter in the current, objectively safe environment can evoke the traumatic experience of combat that took place years earlier. Clinically, PTSD patients relive their traumatic experiences repeatedly, unable to assimilate them as time- and context-limited events. Exposure to trauma and the presence of intrusive symptoms – physiological hyperarousal and avoidance of traumatic reminders – are the core components of PTSD diagnosis. Post-traumatic stress disorder (PTSD) is an incapacitating chronic syndrome involving cognitive, emotional and physiological failure to adequately process and/or recover from exposure to traumatic experience (APA, 1994). The DCOC paradigm offers a promising model for studying the neurobiological basis of contextual modulation of response to potential threat in animals, a process that is disrupted by exposure to severe stress/trauma, and thus might be particularly salient for the study of PTSD.Īnimal model, contextualization, fear conditioning, post-traumatic stress disorder Introduction The PSS and UWT stressors abolished the ability to modulate their responses based on contextual cues, both when exposure preceded DCOC training, and when it followed successfully completed training. Rats trained in the DCOC paradigm acquired the ability to modulate their behavioural responses to odour cue based on contextual cues signalling safe vs. predator scent stress (PSS) and underwater trauma (UWT), on contextual cue discrimination was assessed. The effect of exposure to traumatic stressors, e.g. Response (freezing) to cinnamon odour was tested in a third, neutral environment to examine the ability of animals to modulate their responses based on the contextual cues. In the DCOC paradigm, animals encountered cinnamon odour in both an aversive environment and a rewarding (safe) environment. In order to model this inability to utilize contextualized memory, in an animal model of PTSD, a novel experimental paradigm of contextual cue processing was developed – the differential contextual odour conditioning (DCOC) paradigm – and tested in trauma-exposed animals and controls. Post-traumatic stress disorder (PTSD) patients respond to trauma-related danger cues even in objectively safe environments as if they were in the original event, seemingly unable to adequately modulate their responses based on the contextual cues present.
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