Association Between Microstructural Properties of the Uncinate Fasiculus and Emotion Recognition in Women with and without Autism Spectrum Conditions

Saturday, May 14, 2016: 11:30 AM-1:30 PM
Hall A (Baltimore Convention Center)
A. N. Ruigrok1, M. C. Lai2,3,4, M. V. Lombardo3,5, F. dell'Acqua6, M. Catani6, J. Suckling7,8,9, B. Chakrabarti1,10, D. G. Murphy11, C. MRC AIMS12 and S. Baron-Cohen3,7, (1)Department of Psychiatry, Autism Research Centre, University of Cambridge, Cambridge, United Kingdom, (2)Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan, (3)Autism Research Centre, University of Cambridge, Cambridge, United Kingdom, (4)Centre for Addiction and Mental Health, The Hospital for Sick Children, and Department of Psychiatry, University of Toronto, Toronto, ON, Canada, (5)Department of Psychology and Center for Applied Neuroscience, University of Cyprus, Nikosia, Cyprus, (6)Department of Psychological Medicine and Psychiatry, Section of Brain Maturation, Kings College London, London, United Kingdom, (7)Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom, (8)Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom, (9)Department of Psychiatry, Brain Mapping Unit, University of Cambridge, Cambridge, United Kingdom, (10)School of Psychology & Clinical Language Sciences, University of Reading, Reading, United Kingdom, (11)Sackler Institute for Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences,, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom, (12)Autism Research Centre, University of Cambridge; the Institute of Psychiatry (IoP) at King’s College, London; Autism Research Group, University of Oxford, Cambridge, United Kingdom
Background: Autism spectrum conditions (ASC) are a heterogeneous set of neurodevelopmental conditions. Difficulties with communication and social interactions are some of the main characteristics of ASC. Previous studies have noted potential sex/gender differences in the behavior and brain structural characteristics in individuals ASC, based on studies in which females are frequently outnumbered.

Objectives: This study aims to investigate interactions between neuropsychological tasks measuring emotion recognition and mentalizing and microstructural properties of the uncinate fasciculus (UF; which connects the frontal and temporal lobes) in women with and without ASC.

Methods: 42 age- and IQ-matched women with (n=21) and without ASC were scanned ( 3T GE) using a cardiac-gated 32-direction diffusion-weighted sequence. ExploreDTI was used for preprocessing (Leemans, et al., 2009) and UF deterministic tractography was performed according to guidelines given by Catani & Thiebaut de Schotten (2008) using TrackVis software (http://trackvis.org). Participants completed the “Reading the Mind in the Eyes” (RMET) and the Karolinska Directed Emotional Faces (KDEF) tasks. Number of correct responses was used to test for group differences in performance on the RMET, and log-transformed accuracy-adjusted reaction times (aaRT; mean reaction time divided by accuracy) were used for each individual emotion on the KDEF. A multivariate repeated-measures analysis of covariance (MANCOVA) was performed on fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD) and tract volume respectively, with ‘hemisphere’ as within-subjects factor, ‘diagnosis’ as between-subject factor, and ‘IQ’ as a covariate. Any significant interaction effects were followed up by post-hoc ANCOVAs.

Results: On average, typically developing (TD) females performed better on the RMET (TD, 28.5; ASC, 23.0; F(1,38) = 10.1, p = 0.003) and identified “happy” KDEF expressions faster (TD, 1561ms; ASC, 1925ms; F(1,38) = 9.82, p = 0.003). No group differences were found for other emotional KDEF expressions. There were no group differences in FA, MD, number of streamlines or volume of the UF. Significant hemispheric asymmetries were found across groups for FA and MD, with higher FA (F(1,40) = 31.6, p < 0.001) and lower MD (F(1,40) = 14.9, p < 0.001) in the right UF. In women with ASC, higher FA in the right UF was related to better identification of the “happy” facial expression (TD: r = -0.36, p = 0.12, ASC: r = -0.44, p = 0.05) and higher MD of the right UF was associated with better performance on the RMET (TD: r = -.03, p = 0.89, ASC: r = 0.45, p = 0.04). Fisher’s Z-test was used to compare the correlation coefficients and showed that there were no significant group differences.

Conclusions:  This is the first study that investigates if and how microstructural properties of WM in TD and ASC females relate to socio-emotional task performance. Two significant correlations were found between microstructural properties of the right UF and performance on mentalizing tasks. However, post-hoc Fisher’s Z-test determined that the effect sizes were not significantly different between groups. Future research should investigate if socio-emotional task performance in autism can be predicted by any other WM tracts.