Abstract
Stress exposure can cause lasting changes in cognition, but certain individual traits, such as cognitive flexibility, have been shown to reduce the degree, duration, or severity of cognitive changes following stress. Both stress and cognitive flexibility training affect decision making by modulating monoamine signaling. Here, we test the role cognitive flexibility training, and high vs. low cognitive flexibility at the individual level, in attenuating stress-induced changes in memory and monoamine levels using the single prolonged stress (SPS) rodent model of traumatic stress in male Sprague-Dawley rats. Exposure to SPS can heighten fear responses to conditioned cues (i.e., freezing) after a fear association has been extinguished, referred to as a deficit in extinction retention. This deficit is thought to reflect an impairment in context processing that is characteristic of posttraumatic stress disorder (PTSD). During a cognitive flexibility training we assessed individual variability in cognitive skills and conditioned rats to discriminately use cues in their environment. We found that cognitive flexibility training, alone or followed by SPS exposure, accelerated extinction learning and decreased fear responses over time during extinction retention testing, compared with rats not given cognitive flexibility training. These findings suggest that cognitive flexibility training may improve context processing in individuals with and without traumatic stress exposure. Individual performance during the reversal phase of the cognitive flexibility training predicted subsequent context processing; individuals with high reversal performance exhibited a faster decrease in freezing responses during extinction retention testing. Thus, high reversal performance predicted enhanced retention of extinction learning over time and suggests that cognitive flexibility training may be a strategy to promote context processing. In a brain region vital for maintaining cognitive flexibility and fear suppression, the prelimbic cortex (PLC), cognitive flexibility training also lastingly enhanced dopamine (DA) and norepinephrine (NE) levels, in animals with and without traumatic stress exposure. In contrast, cognitive flexibility training prior to traumatic stress exposure decreased levels of DA and its metabolites in the striatum, a region mediating reflexive decision making. Overall, our results suggest that cognitive flexibility training can provide lasting benefits by enhancing extinction retention, a hallmark cognitive effect of trauma, and prelimbic DA, which can maintain flexibility across changing contexts.
Highlights
Maintaining cognitive flexibility, i.e., the capacity to shift behavioral strategies in a changing environment, is critical to an individual’s ability to update environmental representations
At the level of a trend, cognitive flexibility treatment lowered DOPAC levels in a comparison across all four groups (F(1,26) = 3.58, p < 0.07), and, as with prior DA metabolites, DOPAC levels were lower in animals exposed to both single prolonged stress (SPS) and cognitive flexibility training compared with animals exposed to SPS alone (F(1,15) = 7.06, p = 0.02), but cognitive flexibility treatment alone did not have a detectable effect on DOPAC
We examined whether cognitive flexibility training could buffer effects of traumatic stress on extinction retention, a hallmark deficit of posttraumatic stress disorder (PTSD), and corticostriatal monoamine signaling that maintains cognitive flexibility (Milad et al, 2008, 2009)
Summary
Maintaining cognitive flexibility, i.e., the capacity to shift behavioral strategies in a changing environment, is critical to an individual’s ability to update environmental representations (reviewed in Kehagia et al, 2010). Individuals with low cognitive flexibility have higher levels of posttraumatic stress disorder (PTSD) symptoms and less posttraumatic growth and optimism (Keith et al, 2015). Individuals with heightened cognitive flexibility may have enhanced resilience to change and self-efficacy (Kim and Omizo, 2005; Genet and Siemer, 2011; Mealer et al, 2012; Romero-Martínez et al, 2013). Cognitive flexibility can be heightened through interventions in childhood or adulthood (Masley et al, 2009; Moore and Malinowski, 2009; Genet and Siemer, 2011; Lewis-Morrarty et al, 2012). Investigating whether enhancement in cognitive flexibility, through cognitive training prior to trauma exposure, can reduce PTSD symptoms following trauma, could advance discussions of interventions for resilience and recovery from traumatic experiences
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.
