Disruption of bradycardia associated with discriminative conditioning in combat veterans with PTSD

Disruption of bradycardia associated with discriminative conditioning in combat veterans with PTSD

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Jay P Ginsberg1,2, Edwin Ayers3, Louisa Burriss1, Donald A Powell1,41Shirley L.Buchanan Neuroscience Laboratory, Dorn VA Medical Center, Columbia, SC, USA; 2Department of Pharmacology, Physiology, and Neuroscience, School of Medicine, 4Department of Psychology, University of South Carolina, Columbia, SC, USA; 3Department of Psychology, South Carolina State University, Orangeburg, SC, USAAbstract: The effects of combat-related posttraumatic stress disorder (PTSD) on heart rate (HR) responding associated with a discriminative delay eyeblink (EB) conditioning paradigm are Commercial Vacuum Cleaner reported.Combat PTSD+, Combat PTSD−, and Noncombat PTSD− veterans were assessed with psychometric self-report measures, and baseline heart rate variability (HRV) was measured before receiving a 72-trial session of discriminative EB classical conditioning.Two types (red or green light) of conditioned stimuli (CS) were used: one (CS+) predicted a tone, followed immediately by an aversive stimulus (corneal airpuff); the other (CS−) predicted a tone alone, not followed by the airpuff.

The light signal was presented for 5 seconds, during which HR was measured.On all psychometric Work Gloves measures, the PTSD+ subgroup was significantly different from the PTSD− subgroups (Combat + Noncombat), and the PTSD− subgroups did not significantly differ from each other.A linear deceleration in HR to CS+ and CS− signals was found in the combined PTSD− subgroup and on CS− trials in the PTSD+ subgroup, but was not present on CS+ trials in the PTSD+ subgroup.Results are interpreted with respect to a behavioral stages model of conditioned bradycardia and in terms of neural substrates which are both critical to HR conditioning and known to be abnormal in PTSD.

Keywords: bradycardia, PTSD, combat veterans, classical conditioning.