Esther Direnfeld, Mauricio Garcia-‐Barrera, Rachel Caulfield, Jenna Ha<er, Jeremy Wilson, & Lily Shayegi Nick Department of Psychology, University of Victoria Victoria, B.C., Canada Natalia Trujillo Orrego Grupo de Neurociencias, Universidad de AnFoquia, Medellin, Colombia Elena Perez-‐Hernandez Departmento de Psicologia, Universidad de Zaragoza, Teruel, Spain Results Participants and Methods! Introduction • • • • Studies examining the neural correlates of ADHD have idenCfied total PFC volume differences relaCve to controls, with either smaller volumes of the right or leQ PFC (e.g. Durston et al., 2004; Kates et al., 2002). Some studies have found a linear relaConship between large PFC volume and impaired a>enCon (e.g., Hill et al., 2007). Recent studies have examined subregional volumes of the PFC in greater detail (i.e., dorsolateral, dorsomedial, orbitolateral, & ventromedial). Generally, decreased volumes of regions such as the DLPFC have been observed in children with ADHD compared to controls (e.g., Ha>er et al., 2010; Ranta et al., 2009). Objectives! &! Hypotheses! To determine whether there are small scale structural differences in subregions of the PFC between Spanish children with ADHD and typically developing children, which may help to clarify the nature of the behavioural impairments that are generally observed in children with ADHD. Based on previous studies, we hypothesized that PFC subregions would be smaller in the ADHD group relaFve to controls. • ParCcipants were tested at the Universidad Complutense and the Ruber InternaConal Hospital in Madrid, Spain • Those with ADHD met diagnosCc criteria for ADHD from the DSM-‐IV-‐TR (APA, 2000) • N= 20 with the following distribuCon: ADHD n = 10 Controls n = 10 Age 8.5 (0.71) 8.2 (0.79) Sex 4 females 3 females IQ 95 (16.8) 120 (14.5) • Groups did not differ staCsCcally by age (p = .38), but IQ was significantly lower in the ADHD group (p = .002) relaCve to controls. • All parCcipants were right handed. • MedicaCon (Concerta) for 3 children with ADHD was disconCnued 72 hours prior to tesCng. • Every parCcipant’s parent signed a consent form and subjects received a full neuropsychological assessment. MRI AcquisiKon • GE Signa HDxt 3.0 T scanner • Slices were gapless, collected in the transverse plane, and 1.8 millimeters thick. Image Processing • Images were imported, processed and analyzed using ANALYZE 9.0 (Mayo Clinic, 2009). Pre-‐processing included normalizaCon and AC-‐PC alignment. • Images were manually parcellated following a modified version of the protocol described by Howard et al. (2003). • Then, a combinaCon of a semi-‐automated ROI extracCon and manual tracing was employed to obtain volumes for the leQ and right dorsolateral (DLPFC), dorsomedial (DMPFC), orbitolateral (OLPFC) and ventromedial (VMPFC; oQen called orbitomedial PFC) prefrontal corCces (see Figure 1). • Mann-‐Whitney U analyses were conducted to examine between-‐group differences in PFC subregions • Larger leQ PFC and right DLPFC were found in the ADHD group. • Hierarchical raCos [e.g., LeQ PFC/Total Brain Volume (TBV)] were calculated and used to control for the potenCal effect of larger compartments on subregional volumes. TBV did not explain observed differences. • Both groups showed similar pa>erns of leQ-‐right asymmetry in all PFC regions (ps > .05). Left PFC ) p = .041, r = -.46 ADHD > Controls ( Right DLPFC ) p = .049, r = -.44 ADHD > Controls ( Overall liability ReDiscussion ranged from Intra- rater: ICC .87-1. ranged from .96-1. Inter-rater: ICC Discussion • In contrast to our hypothesis, certain ROIs were significantly larger in the ADHD group compared to the control group. • While our study did not segment white and grey ma>er, it is possible that observed differences were due to delayed pruning and/or maturaCon in the ADHD group. • Some studies (e.g., Shaw et al., 2007) have reported delays in reaching corCcal maturity in prefrontal regions including DLPFC for those with ADHD. • It is also possible that differences in IQ contributed to our findings. A few references Hill, D. E., Yeo, R. A., Campbell, R. A., Hart, B., Vigil, J., & Brooks, W. (2003). MagneCc resonance imaging correlates of a>enCon-‐deficit/hyperacCvity disorder in Durston, children. S., Hulshoff Pol, H. E., Schnack, . G., Buitelaar, J. K., Neuropsychology, 17, 4H96-‐506. Steenhuis, . P., MMinderaa, R. B., et oaf l. the (2004). MagneCc Kates, et al. (M 2002). RI parcellaCon frontal lobe in resonance imaging of boys with a>enCon-‐deficit/ boys with a>enCon deficit hyperacCvity disorder or hyperacCvity disorder aPnd their unaffected J Am toure>e syndrome. sychiatry Research sNiblings. euroimaging, Acad Child Adolesc Psychiatry, 43(3), 332-‐340. 116, 63-‐81. Filipek, P. AE., emrud-‐Clikeman, M., Steingard, R. J., Rtenshaw, Miller, . KS., & Cohen, J. D. (2001). An integraCve heory of P. F., Kennedy, D. N., & Biederman, (1997). Volumetric prefrontal cortex funcCon. JA. nnual Review of MRI analysis comparing subjects having a>enCon-‐deficit Neuroscience, 24, 167-‐202. hyperacCvity wKith normal ontrols. Neurology, 48 Mostofsky, S. Hd., isorder Cooper, . L., Kater, cW . R., Denckla, M. B., (3), Kaufmann, 589-‐601. W. E. (2002). Smaller Prefrontal and Fuster, J. Premotor M. (2008). The Prefrontal Anatomy, Physiology Volumes in Boys Cwortex: ith A>enCon-‐Deficit/ and HyperacCvity Neuropsychology o f t he F rontal L obe, 4 th e d. S an D iego: Disorder. Society of Biological Psychiatry, Academic Press. 52, 785-‐794. Howard, MM . A. E., ., RCoberts, ., &M C. owell, Ranta, rocej, ND., ., GCarcia-‐Finana, lauss, J. A., KM raut, A., P. E. (2003). V olume e sCmaCon of prefrontal corCcal ubfields Mostofsky, S. H., & Kaufmann, W.E.(2009). Msanual MRI using MRI and stereology. Brain Research Protocols, 10, parcellaCon of the frontal lobe. Psychiatry Research: 125-‐138. Neuroimaging, 172, 147-‐154. Shaw, P., Eckstrand, K., Sharp, W., Blumenthal, J., Lerch, J. P., Ha>er, J., Garcia-‐Barrera, . A., Gicas, K., & Hynd., G. W. (2010). Greenstein, D. et M al.(2007). A>enCon-‐deficit/ Small-‐scale volumetric differences in the pbrefrontal of hyperacCvity disorderis characterized y a delay ciortex n children with ADHD and PDNAS, yslexia. Part 2: White ma>er corCcal maturaCon. , 104, 19649-‐19654. subregional differences [Abstract]. JINS, 16(S2), 8. Tranel, D. (2002). EmoCon, decision m aking, and t5he ventromedial prefrontal cortex. In D. T. Struss & R. T. Knight (Eds.), Principles of frontal lobe funcEon (pp. 338-‐353). New York: Oxford University Press. Figure 1
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