Abstract
High levels of emotional arousal can impair spatial memory mediated by the hippocampus, and enhance stimulus-response (S-R) habit memory mediated by the dorsolateral striatum (DLS). The present study was conducted to determine whether these memory systems may be similarly affected in an animal model of post-traumatic stress disorder (PTSD). Sprague-Dawley rats were subjected to a “single-prolonged stress” (SPS) procedure and 1 week later received training in one of two distinct versions of the plus-maze: a hippocampus-dependent place learning task or a DLS-dependent response learning task. Results indicated that, relative to non-stressed control rats, SPS rats displayed slower acquisition in the place learning task and faster acquisition in the response learning task. In addition, extinction of place learning and response learning was impaired in rats exposed to SPS, relative to non-stressed controls. The influence of SPS on hippocampal spatial memory and DLS habit memory observed in the present study may be relevant to understanding some common features of PTSD, including hippocampal memory deficits, habit-like avoidance responses to trauma-related stimuli, and greater likelihood of developing drug addiction and alcoholism.
Highlights
Emotional arousal has a dramatic impact on the function of memory systems in the mammalian brain
Tests of simple main effects using Fisher’s LSD indicated that the proportion of correct turning responses differed significantly between the single-prolonged stress (SPS) and control groups on Training Days 1–3 (p < 0.05), whereas the groups did not differ significantly on Days 4–12 (p > 0.05). These findings suggest that early in training rats previously receiving SPS were impaired in acquisition of place learning, relative to rats in the control group; later in training, SPS and control rats showed comparable memory performance
These findings suggest that animals previously receiving SPS were slightly impaired in extinction of place learning, relative to the control group
Summary
Emotional arousal has a dramatic impact on the function of memory systems in the mammalian brain. In studies employing animals (e.g., rats and mice) and human subjects, very high levels of emotional arousal have been associated with impairments in hippocampus-dependent spatial memory and enhancements in DLS-dependent habit memory (for reviews, see Packard and Goodman, 2012, 2013; Schwabe, 2013; Goodman et al, 2017a). Subjects with post-traumatic stress disorder (PTSD) demonstrate impairments in spatial memory function (Tempesta et al, 2012; Smith et al, 2015; Miller et al, 2017), as well as heightened avoidance responses to trauma-related stimuli (e.g., running away from a loud noise), which may be viewed as an exemplar of enhanced stimulus-response (S-R)/habit memory (for review, see Goodman et al, 2012). Some researchers have proposed that these PTSD symptoms may be partially attributed to the effects of emotional arousal, i.e., stress stemming from the traumatic event, on the hippocampus and dorsolateral striatum (Packard, 2009; Schwabe et al, 2010b; Goodman et al, 2012)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
