F65. Metabolite Abnormalities in the Anterior White Matter of Patients With Pediatric Bipolar Disorder Jonika Tannous 1 , Bo Cao 1 , Jeffrey Stanley 2 , Henrique Amaral-Silva 3 , and Jair Soares 1 1 Univeristy of Texas Health Science Center at Houston, 2 Wayne State University School of Medicine, 3 Siemens Background: Anterior white matter abnormalities have been consistently reported in pediatric bipolar disorder. However, the nature of the metabolites responsible for the functioning of these neural networks in affected bipolar children is poorly understood. Methods: Using a 3-T MRI scanner and LCModel, measure- ments from five anatomically distinct voxels in the anterior white matter were acquired for 49 subjects between the ages of 8 and 18 (17 healthy controls, 16 bipolar, and 16 offspring of bipolar parents). Differences in the mean ratios of glycer- ophosphocholine plus phosphocholine (GPC+PC)/phospho- creatine-creatine (Pcr-Cr) and N-acetylaspartate (NAA)/Pcr-Cr between groups were evaluated with gender and age as covariates. Results: In two of the left anterior white matter voxels, bipolar children had significantly lower NAA/Pcr-Cr (p¼.002; p¼.002) and GPC+PC/Pcr-C (p¼.006; p¼.009) ratios than healthy controls. Ratios of the offspring group were not significantly different than either the bipolar or healthy groups. Conclusions: NAA is a neuronal marker, and a decrease in NAA/Pcr-Cr can be interpreted as a decrease in neuronal integrity. In addition, choline is vital to the structure of neuronal cell membranes. Hence, the observed decrease in NAA and GPC+PC concentrations in bipolar children implies a molecular mechanism behind frontal lobe pathologies. Future work will examine how these findings relate to microstructural measures derived from diffusion tensor imaging. Supported By: NIMH grant R01 085667, the Dunn Research Foundation and the Pat Rutherford, Jr. Endowed Chair in Psychiatry (Jair C. Soares). Keywords: MRS Imaging, Pediatric Bipolar Disorder, Bipolar Offspring F66. The Effect of Traumatic Brain Injury on Superficial White Matter in Youth: Towards a Personalized Injury Profile Sonja Stojanovski 1 , Arash Nazeri 2 , Christian Lepage 3 , Joseph D. Viviano 4 , Aristotle Voineskos 5 , and Anne Wheeler 1 1 Hospital for Sick Children, University of Toronto, 2 Mal- linckrodt Institute of Radiology, 3 Toronto Rehab Institute, 4 Centre for Addiction and Mental Health, 5 University of Toronto, Centre for Addiction and Mental Health (CAMH) Background: Diffusion Tensor Imaging (DTI) studies of trau- matic brain injury (TBI) have focused on alterations in micro- structural features of deep white matter fibers (DWM). Post- mortem studies have demonstrated that injured axons are often observed at the gray-white matter interface beneath the cerebral cortex where superficial white matter fibers (SWM) mediate local connectivity between cortical gyri. The objective of this study was to examine if SWM is at increased risk for injury compared to DWM through group-wise and personalized approaches. Methods: In a community sample of youth (TBI¼10, NoTBI¼70), we analysed DTI data using a SWM mask and tract-based spatial statistics to identify differences in SWM and DWM fractional anisotropy (FA) between groups with and without a history of TBI. To assess personalized injury profiles the number of abnormal FA clusters was compared between DWM and SWM using subject-specific z-score maps in youth with a history of TBI. Results: Group wise comparison of DWM and SWM between youth with and without a history of TBI produced no results that survived threshold free clustering enhancement correc- tion. However, personalized injury profiles revealed a greater number of clusters with reduced FA in SWM compared to DWM in youth with a history of TBI. Conclusions: These results suggest that SWM may be more sensitive than DWM to axonal injury following TBI. Additionally, the heterogeneous nature of TBI may limit the ability of DTI studies to identify regions of microstructural alterations in group wise analyses, thus personalized injury profiles may be a more sensitive biomarker of injury. Supported By: Hospital for Sick Children - Restracomp Keywords: Traumatic Brain Injury, White Matter Microstruc- ture, Short-Distance Tracts, Developing Brain F67. Increased Amygdalar Activation to Angry Faces is Linked to Reduced Prefrontal Cortical Thickness and Hyperactive/Inattentive Symptomatology in Adolescents Matthew Albaugh 1 , Catherine Orr 1 , Philip Spechler 1 , Bader Chaarani 1 , Nicholas Allgaier 1 , Robert Althoff 1 , Nicholas D’Alberto 1 , Kelsey Hudson 1 , Scott Mackey 1 , Claude Lepage 2 , Vladimir S. Fonov 3 , Louis Collins 3 , Pierre Rioux 3 , Hugh Garavan 1 , Alexandra Potter 1 , and James Hudziak 1 1 University of Vermont, 2 Montreal Neurological Institute, 3 McConnell Brain imaging Centre, Montreal Neurological Institute Background: Prior studies have reported increased amyg- dalar activation in response to emotional stimuli among in- dividuals with attention-deficit/hyperactivity disorder (ADHD). Herein, we investigate the extent to which amygdalar activa- tion to angry faces is associated with ADHD symptomology and cortical morphology in a population-based sample of adolescents. Methods: Data were obtained from the IMAGEN study, which includes 2,223 adolescents. While undergoing func- tional imaging, participants passively viewed video clips of a face that started from a neutral expression and progressively turned angry, or, instead, turned to a second neutral expression. Left and right amygdala ROIs were used to extract mean BOLD signal from the angry face minus neutral face contrast for all subjects. T1-weighted images were processed through the CIVET pipeline (version 2.1.0). ADHD Poster Abstracts Biological Psychiatry May 1, 2018; 83:S129eS455 www.sobp.org/journal S263 Biological Psychiatry