Abnormal asymmetry of white matter tracts between ventral posterior cingulate cortex and middle temporal gyrus in recent-onset schizophrenia Sung Woo Joo a , Myong-Wuk Chon a , Yogesh Rathi b , Martha E. Shenton b,c,d , Marek Kubicki b,d , Jungsun Lee a,b, ⁎ a Department of Psychiatry, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea b Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA c VA Boston Healthcare System, Brockton Division, Brockton, MA, USA d Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. abstract article info Article history: Received 18 January 2017 Received in revised form 4 May 2017 Accepted 7 May 2017 Available online xxxx Introduction: Previous studies have reported abnormalities in the ventral posterior cingulate cortex (vPCC) and middle temporal gyrus (MTG) in schizophrenia patients. However, it remains unclear whether the white matter tracts connecting these structures are impaired in schizophrenia. Our study investigated the integrity of these white matter tracts (vPCC-MTG tract) and their asymmetry (left versus right side) in patients with recent onset schizophrenia. Method: Forty-seven patients and 24 age-and sex-matched healthy controls were enrolled in this study. We ex- tracted left and right vPCC-MTG tract on each side from T1W and diffusion MRI (dMRI) at 3 T. We then calculated the asymmetry index of diffusion measures of vPCC-MTG tracts as well as volume and thickness of vPCC and MTG using the formula: 2 × (right - left) / (right + left). We compared asymmetry indices between patients and con- trols and evaluated their correlations with the severity of psychiatric symptoms and cognition in patients using the Positive and Negative Syndrome Scale (PANSS), video-based social cognition scale (VISC) and the Wechsler Adult Intelligence Scale (WAIS-III). Results: Asymmetry of fractional anisotropy (FA) and radial diffusivity (RD) in the vPCC-MTG tract, while present in healthy controls, was not evident in schizophrenia patients. Also, we observed that patients, not healthy con- trols, had a significant FA decrease and RD increase in the left vPCC-MTG tract. There was no significant associa- tion between the asymmetry indices of dMRI measures and IQ, VISC, or PANSS scores in schizophrenia. Conclusion: Disruption of asymmetry of the vPCC-MTG tract in schizophrenia may contribute to the pathophys- iology of schizophrenia. © 2017 Elsevier B.V. All rights reserved. Keywords: Diffusion MRI Schizophrenia Middle temporal gyrus Ventral posterior cingulate cortex Asymmetry 1. Introduction Many studies have used CT or MRI to elucidate the pathogenesis of schizophrenia over the past 40 years (Johnstone et al., 1976; Smith et al., 1985; Kambeitz et al., 2015; Haijma et al., 2013; Bakhshi and Chance, 2015). Although previous studies have reported structural changes in various brain areas in patients with schizophrenia (Chiapponi et al., 2013; Shenton et al., 2001; Haijma et al., 2013; Bakhshi and Chance, 2015), there are few reports of brain areas with consistent abnormalities. These include, but are not limited to, reduced gray matter (GM) volume in the frontal and temporal lobes (Bachmann et al., 2004; Nakamura et al., 2008), decreased total brain volume (Haijma et al., 2013; Veijola et al., 2014; Shenton et al., 2001), decreased volume of hippocampus, and increased ventricles (Steen et al., 2006; van Erp et al., 2016) in schizophrenia patients. Such findings notwith- standing, the association between structural or functional abnormalities in various brain regions and clinical symptoms have been more elusive (Bersani et al., 2014; Samartzis et al., 2014; Nenadic et al., 2012). Further, some studies have reported disconnections as causative. Ev- idence includes abnormalities in myelin and oligodendrocytes (by post- mortem study) and abnormal functional association (by functional im- aging studies) (Sadock et al., 2015; Uranova et al., 2001; Tu et al., 2012; van den Heuvel and Hulshoff Pol, 2010). Diffusion MRI (dMRI) makes it possible to non-invasively investigate the integrity and microstructure of white matter (WM) fiber bundles and their connection among brain regions (Beaulieu, 2002). Findings demonstrate that schizophrenia patients evince irregularities in several Schizophrenia Research xxx (2017) xxx–xxx ⁎ Corresponding author at: Department of Psychiatry, University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea. E-mail address: js_lee@amc.seoul.kr (J. Lee). SCHRES-07298; No of Pages 8 http://dx.doi.org/10.1016/j.schres.2017.05.008 0920-9964/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Schizophrenia Research journal homepage: www.elsevier.com/locate/schres Please cite this article as: Joo, S.W., et al., Abnormal asymmetry of white matter tracts between ventral posterior cingulate cortex and middle temporal gyrus in recent-onset sch..., Schizophr. Res. (2017), http://dx.doi.org/10.1016/j.schres.2017.05.008