Psychology, Sociology and Criminal Justice Research
Effects of Pre-Retrieval Stress on Long-Term Memory Depend on Individual Differences in Corticosteroid Response to Stress
Post-traumatic stress disorder (PTSD) is characterized by cognitive impairments, which may result from intrusive, traumatic memories. One factor potentially influencing the development and maintenance of intrusive memories is prefrontal cortex development, a phenomenon associated with age. The present studies examined how age influences the effects of emotional memories on rat physiology and behavior. Adolescent and adult rats were exposed to predator stress and given water maze training five weeks later. Prior to memory testing, the rats were given a reminder of the predator stress. The results indicated that a reminder of the stress experience impaired long-term spatial memory in the female, adolescent rats only. These findings may have implications for the development of intrusive memories and the increased risk that females have for PTSD.
Blunted Corticosterone Response to Acute Predator Stress Results in Long-Term Spatial Memory Impairment
Clinical research suggests that a blunted corticosteroid response to trauma may be associated with increased risk of developing post-traumatic stress disorder (PTSD). In order to more directly test this hypothesis, we examined the influence of a blunted corticosterone response to stress on the development of PTSD-like behaviors in rats. One-month-old, male Sprague-Dawley rats were injected with metyrapone, an inhibitor or corticosterone synthesis, or vehicle prior to being exposed to an adult female cat for one hour. A week later, the rats were tested for anxiety-like behavior on an elevated plus maze (EPM) and for spatial learning and memory in the radial-arm water maze (RAWM). Analyses of post-stress serum samples verified that metyrapone effectively blocked the stress-induced increase of rat corticosterone levels. Behaviorally, we found that stress, independent of drug, led to an increase in some anxiety-like behaviors (e.g., overall movement, head dips) on the EPM. More importantly, we found that metyrapone administration prior to stress significantly impaired long-term spatial memory in the RAWM. These findings indicate that a blunted corticosteroid response to stress could exacerbate its effects on cognitive performance. Moreover, because anxiety-like behaviors on the EPM were not intensified by the blunted corticosteroid response to stress, our findings also suggest that specific physiological responses to an acute trauma may intensify some, but not all, PTSD-like symptoms.
Alcoholism is a chronic disease that develops as a result of a mixture of genetic, psychosocial, and environmental factors. It is characterized by a continuation of habitual alcohol consumption following the realization that it poses a threat to the individual’s interpersonal relationships and social standing. Addiction to alcohol tends to be progressive and untreatable, partly due to the cognitive distortions that commonly accompany the disease, particularly denial. In addition, alcoholics are distinctive in that they place drinking at a higher priority than obligations. The application of Émile Durkheim’s macro-level theories can provide an understanding of alcoholism in terms of society’s influence on the individual. According to Durkheim, in modern societies, individuals are immersed in both a profane and a sacred reality. Symbols are reminders that occur during the profane reality as reminders of the sacred reality and rituals. Rituals are enacted during the sacred reality and further consolidate the emotions that originally made membership to a group captivating. Durkheim also conceptualized “anomie,” a lack of moral regulation over the individual. The lack of regulation over the treatment of alcohol, in particular, makes modern societies prone to alcoholism. Symbols are constantly compelling individuals to engage in the ritualistic act of drinking through alcohol advertising and surrounding conversations about alcohol. Joining a group with symbols of sobriety can establish a new sacred reality within the individual that thrives on the ability to defeat alcoholism. Despite psychological and genetic factors, a possible cure lies within strong group value systems that provide moral regulation over alcohol, as well as rituals and symbols that make sobriety a new, energizing way of life.
This paper addresses sociopathic behavior from the context of society as a whole. Using Durkheim and Mead takes sociopathy beyond a set of individual characteristics and allows us to look at how the sociopathic individual interacts with society to have an impact on the larger whole. Additionally, by understanding this phenomenon through both structural and interactional lenses we are able to see how patterns in society can affect and are affected by sociopathic individuals.
Interracial adoption is the phenomenon where children of one racial or ethnic group are adopted by parent(s) of another racial or ethnic group. Racial disparities are apparent within the adoption system in the United States. With the increasing acceptance of family structures outside the nuclear family, this work examines the continued reluctance to create interracial families through adoption. Max Weber’s concepts of status, party, rationality and the construction of race are used to address white parents preferring to adopt non-black, minority children, the use of race as a factor in matching a child with a family, the reluctance to the idea of a biracial family, and the hesitancy of black families to interracial adoption more so than white families.
Research has found that emerging adults often report poor sleep quality, which has been connected to problems with mood regulation, academic performance, and accidents. One way to regulate these problems is to practice healthy sleep habits, such as keeping a regular bed time to ensure optimal sleep quality. Additionally, some people with external locus of control, believing events are outside one’s personal control, may disregard their ability to engage in good sleep practices, affecting their overall sleep quality.METHOD: As part of a larger study, Rotter’s Locus of Control (LOC) and the Pittsburgh Sleep Quality Index (PSQI) were utilized to assess college students over the course of an academic term. Participants (N=34) ranged in age from 18-22 (M=19.73) with 19 females and 15 males.
RESULTS: An ANOVA assessing the relationship between LOC and Global PSQI scores indicated a main effect of LOC (p=.045), such that those with an external LOC had higher overall PSQI scores (M=8.59) than those with an internal LOC (M=6.28). An additional ANOVA examining regular bed times and Global PSQI scores showed a main effect of bed time (p=.016), such that those without a regular bed time had higher overall PSQI scores (M=8.47). Furthermore, participants’ scores were above the accepted clinical cutoff of 5 for Global PSQI indicating overall poor sleep quality.CONCLUSION: The results suggest that among emerging adults, an external LOC and not having a regular bed time are associated with worse overall sleep quality than those who have a set bed time and have an internal LOC. These findings suggest that manipulations of one’s locus of control as well as education about sleep hygiene might be a point of intervention for college students to improve sleep quality and, subsequently, academics and mood.
Differential expression of molecular markers of synaptic plasticity in the hippocampus, prefrontal cortex and amygdala in response to spatial learning and predator stress-induced amnesia.
We have studied the effects of spatial learning and predator stress-induced amnesia on the expression of calcium/calmodulin-dependent protein kinase II (CaMKII), brain-derived neurotrophic factor (BDNF) and calcineurin in the hippocampus, basolateral amygdala (BLA), and medial prefrontal cortex (mPFC). Adult male rats were given a single training session in the radial-arm water maze (RAWM) composed of 12 trials followed by a 30-min delay period, during which rats were either returned to their home cages or given inescapable exposure to a cat. Immediately following the 30-min delay period, the rats were given a single test trial in the RAWM to assess their memory for the hidden platform location. Under control (no stress) conditions, rats exhibited intact spatial memory and an increase in phosphorylated CaMKII (p-CaMKII), total CaMKII, and BDNF in dorsal CA1. Under stress conditions, rats exhibited impaired spatial memory and a suppression of all measured markers of molecular plasticity in dorsal CA1. The molecular profiles observed in the BLA, mPFC, and ventral CA1 were markedly different from those observed in dorsal CA1. Stress exposure increased p-CaMKII in the BLA, decreased p-CaMKII in the mPFC, and had no effect on any of the markers of molecular plasticity in ventral CA1. These findings provide novel observations regarding rapidly induced changes in the expression of molecular plasticity in response to spatial learning, predator exposure, and stress-induced amnesia in brainregions involved in different aspects of memory processing.
Epigenetic modification of hippocampal BDNF DNA in adult rats in an animal model of post-traumatic stress disorder.
Epigenetic alterations of the brain-derived neurotrophic factor (Bdnf) gene have been linked with memory, stress, and neuropsychiatric disorders. Here we examined whether there was a link between an established rat model of post-traumatic stress disorder (PTSD) and Bdnf DNA methylation. Adult male Sprague–Dawley rats were given psychosocial stress composed of two acute cat exposures in conjunction with 31 days of daily social instability. These manipulations have been shown previously to produce physiological and behavioral sequelae in rats that are comparable to symptoms observed in traumatized people with PTSD. We then assessed Bdnf DNA methylation patterns (at exon IV) and gene expression. We have found here that the psychosocial stress regimen significantly increased Bdnf DNA methylation in the dorsal hippocampus, with the most robust hypermethylation detected in the dorsal CA1 subregion. Conversely, the psychosocial stress regimen significantly decreased methylation in the ventral hippocampus (CA3). No changes in Bdnf DNA methylation were detected in the medial prefrontal cortex or basolateral amygdala. In addition, there were decreased levels of Bdnf mRNA in both the dorsal and ventral CA1. These results provide evidence that traumatic stress occurring in adulthood can induce CNS gene methylation, and specifically, support the hypothesis that epigenetic marking of the Bdnf gene may underlie hippocampal dysfunction in response to traumatic stress. Furthermore, this work provides support for the speculative notion that altered hippocampal Bdnf DNA methylation is a cellular mechanism underlying the persistent cognitive deficits which are prominent features of the pathophysiology of PTSD.
Pre-learning stress differentially affects long-term memory for emotional words, depending on temporal proximity to the learning experience.
Stress exerts a profound, yet complex, influence on learning and memory and can enhance, impair or have no effect on these processes. Here, we have examined how the administration of stress at different times before learning affects long-term (24-hr) memory for neutral and emotional information. Participants submerged their dominant hand into a bath of ice cold water (Stress) or into a bath of warm water (No Stress) for 3 min. Either immediately (Exp. 1) or 30 minutes (Exp. 2) after the water bath manipulation, participants were presented with a list of 30 words varying in emotional valence. The next day, participants’ memory for the word list was assessed via free recall and recognition tests. In both experiments, stressed participants exhibited greater blood pressure, salivary cortisol levels, and subjective pain and stress ratings than non-stressed participants in response to the
water bath manipulation. Stress applied immediately prior to learning (Exp. 1) enhanced the recognition of positive words, while stress applied 30 min prior to learning (Exp. 2) impaired free recall of negative words. Participants’ recognition of positive words in Experiment 1 was positively associated with their heart rate responses to the water bath manipulation, while participants’ free recall of negative words in Experiment 2 was negatively associated with their blood pressure and cortisol responses to the water bath manipulation. These findings indicate that the differential effects of pre-learning stress on long-term memory may depend on the temporal proximity of the stressor to the learning experience and the emotional nature of the to-be-learned information.