Prior structural imaging studies of post-traumatic stress disorder (PTSD) have observed smaller volumes of the hippocampus and cingulate cortex, yet little is known about the integrity of white matter connections between these structures in PTSD samples. The few published studies using diffusion tensor imaging (DTI) to measure white matter integrity in PTSD have described individuals with focal trauma rather than chronically stressed individuals, which limits generalization of findings to this population; in addition, these studies have lacked traumatized comparison groups without PTSD. The present DTI study examined microstructural integrity of white matter tracts in a sample of highly traumatized African-American women with (n ¼ 25) and without (n ¼ 26) PTSD using a tract-based spatial statistical approach, with threshold-free cluster enhancement. Our findings indicated that, relative to comparably traumatized controls, decreased integrity (measured by fractional anisotropy) of the posterior cingulum was observed in participants with PTSD (po0.05). These findings indicate that reduced microarchitectural integrity of the cingulum, a white matter fiber that connects the entorhinal and cingulate cortices, appears to be associated with PTSD symptomatology. The role of this pathway in problems that characterize PTSD, such as inadequate extinction of learned fear, as well as attention and explicit memory functions, are discussed.

Pediatric neuro-oncology researchers face methodological challenges associated with quantifying the influence of tumor and treatment-related risk factors on child outcomes. The Neurological Predictor Scale was developed to serve as a cumulative index of a child's exposure to risk factors. The clinical utility of the Neurological Predictor Scale was explored in a sample of 25 children with heterogeneous brain tumors. Consistent with expectation, a series of regression analyses demonstrated that the Neurological Predictor Scale significantly predicted composite intellectual functioning (r(2) = 0.21, p < .05), short-term memory (r(2) = 0.16, p = .05), and abstract visual reasoning abilities (r(2) = 0.28, p < .05). With the exception of chemotherapy, the Neurological Predictor Scale accounted for a significant amount of the variance in child intellectual functioning above and beyond individually examined variables. The Neurological Predictor Scale can be used to quickly quantify the cumulative risk factors associated with pediatric brain tumor diagnoses.

Previous research on police officer shoot decisions has focussed on the influence of situational factors that lead to the shooting error. Focussing instead on the 'shooter', the present study examined whether working memory capacity and threat-related increases in negative emotionality influenced participant shoot decisions in a simulated shooting task. Following a working memory test, 24 police officers viewed a police-relevant threatening video while physiological indices of arousal and negative affect were obtained and then completed a computerized shoot-don't shoot task. Results indicated that lower working memory capacity was associated with a greater likelihood of shooting unarmed targets and a failure to shoot armed targets. Moreover, an interaction effect indicated that these associations were only significant for officers who experienced heightened negative emotionality in response to the video. Results suggest that when negatively aroused via threat, limited working memory capacity increases the risk of shooting error.

Alterations in the microarchitecture of the posterior cingulum (PC), a white matter tract proximal to the hippocampus that facilitates communication between the entorhinal and cingulate cortices, have been observed in individuals with psychiatric disorders, such as depression and post-traumatic stress disorder (PTSD). PC decrements may be a heritable source of vulnerability for the development of affective disorders; however, genetic substrates for these white matter abnormalities have not been identified. The FKBP5 gene product modulates glucocorticoid receptor function and has been previously associated with differential hippocampal structure, function, and affect disorder risk. Thus, FKBP5 is an attractive genetic target for investigations of PC integrity. We examined associations between PC integrity, measured through diffusion tensor imaging (DTI) and fractional anisotropy (FA; an index of white matter integrity), and polymorphisms in the FKBP5 SNP rs1360780 in a sample of 82 traumatized female civilians. Findings indicated that, compared with individuals without this allele, individuals who carried two 'risk' alleles for this FKBP5 SNP (T allele; previously associated with mood and anxiety disorder risk) demonstrated significantly lower FA in the left PC, even after statistically controlling for variance associated with age, trauma exposure, and PTSD symptoms. These data suggest that specific allelic variants for an FKBP5 polymorphism are associated with decrements in the left PC microarchitecture. These white matter abnormalities may be a heritable biological marker that indicates increased vulnerability for the development of psychiatric disorders, such as PTSD.

Childhood brain tumors and related treatments disrupt the developing brain and have a cascading impact on core cognitive skills and intellectual (intelligence quotient [IQ]) and academic achievement outcomes. Theoretical models for this cascade have been developed based on the literature, but no studies thus far have empirically evaluated the models. The current study aimed to empirically test the two extant models and generate a new data-driven model of the relationships among neurodevelopmental risk factors, core cognitive skills (i.e., processing speed, attention span, working memory), and IQ and achievement outcomes. Fifty-seven adult survivors of childhood brain tumors and fifty-seven demographically matched neurotypical individuals were included in the current study. The average age at brain tumor diagnosis was 8 years, and the average time since diagnosis was 17 years. Three a priori path models tested the hypothesized relationships among variables. Results of the path analyses revealed that the hybrid model best fit the data for both survivors and controls based on all statistical criteria. For survivors, processing speed was the core cognitive skill most widely associated with neurodevelopmental risk factors and outcomes. However, working memory and attention span also had unique contributions to IQ and academic achievement. Processing speed appears to be the central cognitive skill that disrupts the other core cognitive skills of attention span and working memory, and all three make a unique contribution to IQ and academic achievement. This is best demonstrated by a novel neurodevelopmental model that combines components of two earlier untested theoretical models.