Publications (30) View all
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Article: The interacting role of media violence exposure and aggressive-disruptive behavior in adolescent brain activation during an emotional Stroop task.
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ABSTRACT: Only recently have investigations of the relationship between media violence exposure (MVE) and aggressive behavior focused on brain functioning. In this study, we examined the relationship between brain activation and history of media violence exposure in adolescents, using functional magnetic resonance imaging (fMRI). Samples of adolescents with no psychiatric diagnosis or with disruptive behavior disorder (DBD) with aggression were compared to investigate whether the association of MVE history and brain activation is moderated by aggressive behavior/personality. Twenty-two adolescents with a history of aggressive behavior and diagnosis of either conduct disorder or oppositional-defiant disorder (DBD sample) and 22 controls completed an emotional Stroop task during fMRI. Primary imaging results indicated that controls with a history of low MVE demonstrated greater activity in the right inferior frontal gyrus and rostral anterior cingulate during the violent word condition. In contrast, in adolescents with DBD, those with high MVE exhibited decreased activation in the right amygdala, compared with those with low MVE. These findings are consistent with research demonstrating the importance of fronto-limbic structures for processing emotional stimuli, and with research suggesting that media violence may affect individuals in different ways depending on the presence of aggressive traits.Psychiatry Research 03/2011; 192(1):12-9. · 2.52 Impact Factor -
Article: Executive functioning characteristics associated with ADHD comorbidity in adolescents with disruptive behavior disorders.
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ABSTRACT: The nature of executive dysfunction in youth with disruptive behavior disorders (DBD) remains unclear, despite extensive research in samples of children with attention-deficit hyperactivity disorder (ADHD). To determine the relationship between DBD, ADHD, and executive function deficits in aggressive teens, adolescents with DBD and comorbid ADHD (DBD + ADHD; n = 25), DBD without ADHD (DBD-ADHD; n = 23), and healthy controls (HC; n = 25) were compared on neurocognitive tests and questionnaires measuring executive functioning. Teens with DBD + ADHD performed worse on both neurocognitive and questionnaire measures of executive function than the DBD-ADHD and HC groups. Results suggest that subgroups of DBD may exist depending on the presence or absence of comorbid ADHD, which may have implications for the selection and efficacy of treatment strategies.Journal of Abnormal Child Psychology 01/2011; 39(1):11-9. · 3.09 Impact Factor -
Article: Short Term Exposure to a Violent Video Game Induces Changes in Frontolimbic Circuitry in Adolescents
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ABSTRACT: Despite evidence of effects of violent video game play on behavior, the underlying neuronal mechanisms involved in these effects remain poorly understood. We report a functional MRI (fMRI) study during two modified Stroop tasks performed immediately after playing a violent or nonviolent video game. Compared with the violent video game group, the nonviolent video game group demonstrated more activation in some regions of the prefrontal cortex during the Counting Stroop task. In contrast to the violent video game group, significantly stronger functional connectivity between left dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) was identified in the nonviolent video game group. During an Emotional Stroop task, the violent video game group showed more activity in the right amygdala and less activation in regions of the medial prefrontal cortex (MPFC). Furthermore, functional connectivity analysis revealed the negative coupling between right amygdala and MPFC in the nonviolent video game group. By contrast, no significant functional connectivity between right amygdala and MPFC was found in the violent video game group. These results suggest differential engagement of neural circuitry in response to short term exposure to a violent video game as compared to a nonviolent video game.Brain Imaging and Behavior 02/2009; 3(1):38-50. · 1.66 Impact Factor -
Article: Seizure recurrence risk following a first seizure in neurologically normal children.
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ABSTRACT: To define seizure recurrence rates in normal children who had had a single seizure and to define electroencephalography (EEG) or magnetic resonance imaging (MRI) utility in predicting seizure recurrence. We studied 150 children (6 to 14 years) with a first afebrile, unprovoked seizure. Inclusion criteria were: Normal physical and neurological examination, undergone EEG and MRI studies of the brain, and followed for at least 27 months. These children participated in an ongoing prospective study of new onset seizures in childhood. The seizure recurrence rate was 66.4%. An abnormal EEG had no association with seizure recurrence at 9, 18, or 27 months (p = 0.1806, p = 0.2792, and p = 0.2379, respectively). A "significant" MRI abnormality, which occurred in 16.0% of patients, was associated with an increased seizure recurrence risk at 9 months (p = 0.0389) but not at 18 or 27 months. EEG findings poorly predict recurrence after a single seizure. The high rate of MRI abnormalities suggests that MRI may need consideration as a routine test to evaluate epilepsy in normal children.Epilepsia 12/2008; 49(11):1950-4. · 3.96 Impact Factor -
Article: White matter abnormalities associated with disruptive behavior disorder in adolescents with and without attention-deficit/hyperactivity disorder.
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ABSTRACT: Disruptive behavior disorders (DBD) are among the most commonly diagnosed mental disorders in children and adolescents. Some important characteristics of DBD vary based on the presence or absence of comorbid attention-deficit/hyperactivity disorder (ADHD), which may affect the understanding of and treatment decision-making related to the disorders. Thus, identifying neurobiological characteristics of DBD with comorbid ADHD (DBD+ADHD) can provide a basis to establish a better understanding of the condition. This study aimed to assess abnormal white matter microstructural alterations in DBD+ADHD as compared to DBD alone and healthy controls using diffusion tensor imaging (DTI). Thirty-three DBD (19 with comorbid ADHD) and 46 age-matched healthy adolescents were studied using DTI. Fractional anisotropy (FA), and mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD) were analyzed using tract-based spatial statistics (TBSS). Significantly lower FA and higher MD, RD and AD in many white matter fibers were found in adolescents with DBD+ADHD compared to controls. Moreover, lower FA and higher RD were also found in the DBD+ADHD versus the DBD alone group. Alterations of white matter integrity found in DBD patients were primarily associated with ADHD, suggesting that ADHD comorbidity in DBD is reflected in greater abnormality of microstructural connections.Psychiatry Research 06/2012; 202(3):245-51. · 2.52 Impact Factor
