Faculty Bibliography

Research has established that both exposure to community violence and family functioning are predictive of various forms of psychological distress in adolescents. This study examined whether predictors in this area interact in such a way that the relation of community violence exposure to psychological distress in serious male juvenile offenders is moderated by caregiver-adult support and caregiver control. A heterogeneous sample of 116 male incarcerated adolescents (aged 12-18) was administered measures evaluating exposure to community violence, caregiver-adult support and control, and different forms of psychological distress. As expected, a significant caregiver-adult support by violence exposure interaction was found for alcohol/drug use and depression/anxiety. The implications of the findings for understanding and treating serious male juvenile offenders are discussed.

Consistent evidence shows both genetic and stress-related risks on child and adolescent anxiety, yet few studies have considered the degree to which genetic effects are moderated by stress (gene-environment interaction). We used longitudinal data from both a child and adolescent sample of twins to examine three novel issues on the presence of gene-environment interaction on anxiety symptoms. First, we assessed moderation of genetic risks on anxiety symptoms by negative life events in each age group. Second, by distinguishing between "stable" and "age-specific" genetic factors, we explored the continuity of gene-environment interaction across time and/or its emergence at specific ages. Third, we compared the presence of gene-environment interaction across different symptom types (general, panic, social, and separation). Genetic effects on separation anxiety symptoms in childhood (mean age = 8 years, 6 months) and panic anxiety symptoms in adolescence (mean age = 15 years) increased across independent negative life events. Shared environmental effects on separation anxiety symptoms and non shared environmental effects on general anxiety symptoms in adolescence were also moderated by negative life events. We interpret these preliminary findings tentatively in the context of gene-environment interaction on anxiety in general, and on early separation and later panic anxiety in particular.

Regional volumetric and local shape analysis has become of increasing interest to the neuroimaging community due to the potential to locate morphological changes. In this paper we compare three common correspondence methods applied to two studies of hippocampal shape in schizophrenia: correspondence via deformable registration, spherical harmonics (SPHARM) and Minimum Description Length (MDL) optimization. These correspondence methods are evaluated in respect to local statistical shape analysis and structural subdivision analysis. Results show a non-negligible influence of the choice of correspondence especially in studies with low numbers of subjects. The differences are especially striking in the structural subdivision analysis and hints at a possible source for the diverging findings in many subdivision studies. Our comparative study is not meant to be exhaustive, but rather raises awareness of the issue and shows that assessing the validity of the correspondence is an important step.

Seizure induction in laboratory animals is followed by many changes in structure and function, and one of these is an increase in neurogenesis-the birth of new neurons. This phenomenon may be relevant to temporal lobe epilepsy (TLE), because one of the regions of the brain where seizure-induced neurogenesis is most robust is the dentate gyrus-an area of the brain that has been implicated in the pathophysiology of TLE. Although initial studies predicted that neurogenesis in the dentate gyrus would be important to normal functions, such as learning and memory, the new neurons that are born after seizures may not necessarily promote normal function. There appears to be a complex functional and structural relationship between the new dentate gyrus neurons and preexisting cells, both in the animal models of TLE and in tissue resected from patients with intractable TLE. These studies provide new insights into the mechanisms of TLE, and suggest novel strategies for intervention that could be used to prevent or treat TLE