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UNLABELLED - Early institutional care can be profoundly stressful for the human infant, and, as such, can lead to significant alterations in brain development. In animal models, similar variants of early adversity have been shown to modify amygdala-hippocampal-prefrontal cortex development and associated aversive learning. The current study examined this rearing aberration in human development. Eighty-nine children and adolescents who were either previously institutionalized (PI youth; N = 46; 33 females and 13 males; age range, 7-16 years) or were raised by their biological parents from birth (N = 43; 22 females and 21 males; age range, 7-16 years) completed an aversive-learning paradigm while undergoing functional neuroimaging, wherein visual cues were paired with either an aversive sound (CS+) or no sound (CS-). For the PI youth, better aversive learning was associated with higher concurrent trait anxiety. Both groups showed robust learning and amygdala activation for CS+ versus CS- trials. However, PI youth also exhibited broader recruitment of several regions and increased hippocampal connectivity with prefrontal cortex. Stronger connectivity between the hippocampus and ventromedial PFC predicted significant improvements in future anxiety (measured 2 years later), and this was particularly true within the PI group. These results suggest that for humans as well as for other species, early adversity alters the neurobiology of aversive learning by engaging a broader prefrontal-subcortical circuit than same-aged peers. These differences are interpreted as ontogenetic adaptations and potential sources of resilience.
SIGNIFICANCE STATEMENT - Prior institutionalization is a significant form of early adversity. While nonhuman animal research suggests that early adversity alters aversive learning and associated neurocircuitry, no prior work has examined this in humans. Here, we show that youth who experienced prior institutionalization, but not comparison youth, recruit the hippocampus during aversive learning. Among youth who experienced prior institutionalization, individual differences in aversive learning were associated with worse current anxiety. However, connectivity between the hippocampus and prefrontal cortex prospectively predicted significant improvements in anxiety 2 years following scanning for previously institutionalized youth. Among youth who experienced prior institutionalization, age-atypical engagement of a distributed set of brain regions during aversive learning may serve a protective function.
Copyright © 2016 the authors 0270-6474/16/366421-11$15.00/0.
This study examined concordance between physiological arousal and subjective distress during a laboratory challenge task. Data were collected during the multisite VA Cooperative Study 334 in the early 1990s examining psychophysiological arousal among combat-exposed Vietnam veterans with (n = 775) and without (n = 369) posttraumatic stress disorder (PTSD). Study participants were presented with 6 standardized neutral scenes and 6 standardized combat scenes. Participants provided a subjective rating of distress after each slide. During the presentation, levels of heart rate (HR) and skin conductance (SC) were recorded. Using linear mixed effects modeling, both HR level and SC level exhibited significant positive associations with subjective distress ratings (pr = .33, p < .001 and pr = .19, p < .001, respectively). Individuals with PTSD demonstrated greater concordance between their distress ratings and SC level during exposure to combat slides than participants without PTSD (pr = .28, p < .001 vs. pr = .18, p < .001). Although a significant association was found between subjective distress and HR reactivity and SC reactivity, these findings were not moderated by PTSD status. The results of these analyses suggest that patients' reports of distress during exposure-based treatments might serve as approximate measures of actual physiological arousal.
Copyright © 2012 International Society for Traumatic Stress Studies.
OBJECTIVE - To examine the validity of using sternal skin conductance monitoring as a measure of hot flash intensity and hot flash distress.
DESIGN - Descriptive, prospective, longitudinal data from the 2-week baseline of a larger hot flash intervention study; 73 breast cancer survivors with daily hot flashes wore a hot flash monitor and completed a hot flash diary during two 24-hour assessment periods that were separated in time by 1 week.
RESULTS - Data consisted of 569 diary rated hot flashes; 46.9% had magnitude of less than 2.0 micromhos (insufficient to meet objective hot flash criterion) and 26.3% had magnitude of 0.0 micromho (no change in skin conductance). Results from mixed-linear modeling indicated that, although magnitude significantly predicted hot flash intensity and distress, effect sizes were very small: less than 2% when using all observations, and less than 1% when using only the subset meeting objective hot flash criteria. Even after adjusting for covariates that were associated with intensity or distress, magnitude explained very little variance in intensity or distress (<2.2%). Scatterplots and locally weighted smooth regression curves also revealed very little relationship between magnitude and either intensity or distress.
CONCLUSIONS - Findings indicate that objective change in sternal skin conductance, an indicator of sweat gland activity, should not be used as a proxy measure of subjective hot flash intensity or distress. Future research should continue to subjectively measure hot flash intensity and distress when these are important outcome variables to consider.