Digital embryos: a novel technical approach to investigate perceptual categorization in pigeons (Columba livia) using machine learning

Animal Cognition - Pigeons are classic model animals to study perceptual category learning. To achieve a deeper understanding of the cognitive mechanisms of categorization, a careful consideration...     

Genetic influences on the overlap between low IQ and antisocial behavior in young children

The well-documented relation between the phenotypes of low IQ and childhood antisocial behavior could be explained by either common genetic influences or environmental influences. These competing explanations were examined through use of the Environmental Risk Longitudinal Twin Study 1994-1995 cohort (Moffitt & the E-Risk Study Team, 2002) of 1,116 twin pairs and their families. Children's IQ was assessed via individual testing at age 5 years. Mothers and teachers reported on children's antisocial behavior at ages 5 and 7 years. Low IQ was related to antisocial behavior at age 5 years and predicted relatively higher antisocial behavior scores at age 7 years when antisocial behavior at age 5 years was controlled. This association was significantly stronger among boys than among girls. Genetic influences common to both phenotypes explained 100% of the low IQ-antisocial behavior relation in boys. Findings suggest that specific candidate genes and neurobiological processes should be tested in relation to both phenotypes.     

The direct and indirect benefits of dispositional mindfulness on self-esteem and social anxiety

This study investigated the long‐term health effects of combat stress reaction (CSR) among Israeli CSR casualties (112) and control veterans (184) of the 1973 Yom Kippur war. Posttraumatic stress disorder (PTSD), physical symptoms, and adverse health practices were examined 18 years after the war. The relationship between CSR, PTSD, physical symptoms and adverse health practices was examined via hierarchical linear regression. Findings indicate that although CSR was positively associated with more current physical symptoms and adverse health practices in univariate analyses, these associations were not significant once demographic differences between the groups were controlled. In contrast, current PTSD symptoms were positively associated with current physical symptoms (p < 0.001) and showed a trend association with adverse health practices (p = 0.06). PTSD was the most powerful predictor of current physical symptoms and appears to mediate the association between CSR and physical symptoms almost two decades after the war. Both combat stress reaction and the results of the study were discussed in the light of the theory of Conservation of Resources (COR).     

Trajectories of Posttraumatic Stress Among Urban Residents

Urban residents experience a wide range of traumatic events and are at increased risk of assaultive violence. Although previous research has examined trajectories of posttraumatic stress (PTS) through latent class growth analysis (LCGA) among persons exposed to the same index events (e.g., a natural disaster), PTS trajectories have not been documented among urban residents. The aims of this study were to conduct LGCA with a sample of trauma survivors from Detroit, Michigan (N = 981), and to explore predictors of trajectory membership. Participants completed three annual telephone surveys, each of which included the posttraumatic stress disorder (PTSD) Checklist-Civilian Version. Four PTS trajectories were detected. Although the majority evidenced a trajectory of consistently few symptoms (Low: 72.5 %), 4.6 % were in a trajectory of chronic severe PTSD (High), and the remainder were in trajectories of consistently elevated, but generally subclinical, levels of PTS (Decreasing: 12.3 %; Increasing: 10.6 %). Socioeconomic disadvantage (e.g., lower income), more extensive trauma history (e.g., childhood abuse), and fewer social resources (e.g., lower social support) were associated with membership in higher PTS trajectories, relative to the Low trajectory. The results suggest that efforts to reduce PTS in urban areas need to attend to socioeconomic vulnerabilities in addition to trauma history and risk for ongoing trauma exposure.     

The developmental mental-disorder histories of adults with posttraumatic stress disorder: a prospective longitudinal birth cohort study

Clinical and epidemiologic studies have established that posttraumatic stress disorder (PTSD) is highly comorbid with other mental disorders. However, such studies have largely relied on adults' retrospective reports to ascertain comorbidity. The authors examined the developmental mental health histories of adults with PTSD using data on mental disorders assessed across the first 3 decades of life among members of the longitudinal Dunedin Multidisciplinary Health and Development Study; 100% of those diagnosed with past-year PTSD and 93.5% of those with lifetime PTSD at age 26 had met criteria for another mental disorder between ages 11 and 21. Most other mental disorders had first onsets by age 15. Of new cases of PTSD arising between ages 26 and 32, 96% had a prior mental disorder and 77% had been diagnosed by age 15. These data suggest PTSD almost always develops in the context of other mental disorders. Research on the etiology of PTSD may benefit from taking lifetime developmental patterns of comorbidity into consideration. Juvenile mental-disorder histories may help indicate which individuals are most likely to develop PTSD in populations at high risk of trauma exposure.     

Posttraumatic Stress Symptoms and Trajectories in Child Sexual Abuse Victims: An Analysis of Sex Differences Using the National Survey of Child and Adolescent Well-Being

Very few studies have prospectively examined sex differences in posttraumatic stress symptoms and symptom trajectories in youth victimized by childhood sexual abuse. This study addresses that question in a relatively large sample of children, drawn from the National Survey of Child and Adolescent Well-Being, who were between the ages of 8–16 years and who were reported to Child Protective Services for alleged sexual abuse. Sex differences were examined using t tests, logistic regression, and latent trajectory modeling. Results revealed that there were not sex differences in victims’ posttraumatic stress symptoms or trajectories. Whereas caseworkers substantiated girls’ abuse at higher rates than boys’ abuse and rated girls significantly higher than boys on level of harm, there were not sex differences in three more objective measures of abuse severity characteristics. Overall, higher caseworker ratings of harm predicted higher initial posttraumatic stress symptom levels, and substantiation status predicted shallower decreases in trauma symptoms over time. Implications for theory and intervention are discussed.     

Measures of prefrontal system dysfunction in posttraumatic stress disorder

Clinical observations have suggested that individuals who have suffered traumatic stressful events exhibit disruption in abilities mediated by frontal brain systems. Therefore, this study employed tasks sensitive to frontal lobe dysfunction, including delayed response (DR), delayed alternation (DA), object alternation (OA), delayed matching-to-sample (DMTS), and delayed nonmatching-to-sample (DNMTS), with participants having posttraumatic stress disorder (PTSD). Compared to controls, the PTSD participants were unimpaired on DA and DMTS, but they showed deficits on DR, OA, and DNMTS tasks. This pattern of results suggests disruption of functioning in selective prefrontal brain systems. Results are discussed in the context of the neuropsychological features of PTSD, as well as possible neuropathological and etiological underpinnings of this disorder.     

The impact of borderline personality disorder on process group outcome among women with posttraumatic stress disorder related to childhood abuse.

The outcome of a 12-week interpersonal process group therapy for women with postraumatic Stress Disorder (PTSD) related to childhood sexual abuse with and without borderline personality disorder (BPD) was assessed by comparing three naturally occurring treatment conditions: groups that did not have any members with borderline personality disorder (BPD-) (n = 18), groups in which at least one member carried the diagnosis (BPD+)(n = 16), and a 12-week waitlist (WL) (n = 15). PTSD, anger, depression, and other symptoms were significantly reduced in the BPD- groups. However, the BPD+ and WL conditions did not show any pre- to posttreatment improvements. Furthermore, the BPD+ condition showed a significant worsening on measures of anger. Analyses within the BPD+ condition indicated that women with and without the diagnosis experienced equal posttreatment increases in anger problems. These latter results suggest the presence of an anger "contagion" effect. That is, women without BPD did well in the BPD- groups but showed increased anger similar to the BPD+ women when treated in groups with them. Implications for client-treatment matching considerations in PTSD group therapy are discussed.     

Categories in the pigeon brain: A reverse engineering approach

Pigeons are well known for their visual capabilities as well as their ability to categorize visual stimuli at both the basic and superordinate level. We adopt a reverse engineering approach to study categorization learning: Instead of training pigeons on predefined categories, we simply present stimuli and analyze neural output in search of categorical clustering on a solely neural level. We presented artificial stimuli, pictorial and grating stimuli, to pigeons without the need of any differential behavioral responding while recording from the nidopallium frontolaterale (NFL), a higher visual area in the avian brain. The pictorial stimuli differed in color and shape; the gratings differed in spatial frequency and amplitude. We computed representational dissimilarity matrices to reveal categorical clustering based on both neural data and pecking behavior. Based on neural output of the NFL, pictorial and grating stimuli were differentially represented in the brain. Pecking behavior showed a similar pattern, but to a lesser extent. A further subclustering within pictorial stimuli according to color and shape, and within gratings according to frequency and amplitude, was not present. Our study gives proof‐of‐concept that this reverse engineering approach—namely reading out categorical information from neural data—can be quite helpful in understanding the neural underpinnings of categorization learning.