UNCORRECTED PROOF NSY 2406 1–7 NSY 2406 1–7 Neuropsychologia xxx (2006) xxx–xxx Sex determines the neurofunctional predictors of visual word learning 3 Chuansheng Chen a,∗ , Gui Xue b , Qi Dong c,∗∗ , Zhen Jin d , Tian Li c , Feng Xue c , Libo Zhao c , Yi Guo c 4 5 a Department of Psychology and Social Behavior, University of California, Irvine, CA 92697-7085, USA 6 b FPR-UCLA Center for Culture, Brain and Development, University of California, Los Angeles, CA 90095-1563, USA 7 c State Key Laboratory of Cognitive Neuroscience and Learning, Institute of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, PR China 8 9 d MRI Center, Beijing 306 Hospital, Beijing, PR China 10 Received 31 March 2006; received in revised form 10 August 2006; accepted 12 August 2006 11 Abstract 12 This study used functional MRI and an artificial language training paradigm to explore sex differences in the processing of a new writing system and how sex determines the optimal neural resource recruitment for visual word learning. Results indicated that males and females achieved equal learning outcome, and their learning curve followed a similar power function. They also showed similar overall activation in the fusiform cortex, a region that has been associated with visual word processing. Despite the absence of sex differences in averaged behav- ioral performance and neural activation, males and females were found to have different neural predictors of visual word learning. As predicted, left-lateralized fusiform activation predicted visual word learning for males, but not for females, whereas bilateral fusiform activation predicted visual word learning for females, but not males. These results suggest that male and female brains operate differently to achieve the best perfor- mance in visual word learning. The individual-differences approach adopted in the present study provides a new and useful perspective to sex differences. 13 14 15 16 17 18 19 20 21 © 2006 Elsevier Ltd. All rights reserved. 22 Keywords: Asymmetry; fMRI; Visual word learning; Individual differences; Sex differences 23 24 Sex differences in the neural representation of language 25 are an important issue in cognitive neuroscience. It has long 26 been hypothesized that language is more strongly lateralized 27 for males than for females. For example, it has been found that 28 early brain damage in the left-hemisphere impairs only males’ 29 but not females’ reading ability (e.g., Frith & Vargha-Khadem, 30 2001). Some neuroimaging studies have shown that males 31 show more left-lateralized activation whereas females show 32 more bilateral activation in language tasks (Kansaku, Yamaura, 33 & Kitazawa, 2000; McGlone, 1980; Shaywitz et al., 1995), 34 although others did not find such differences (Frost et al., 35 1999; Sommer, Aleman, Bouma, & Kahn, 2004). These results 36 suggest that different neural resources may be optimal for males 37 ∗ Corresponding author. Tel.: +1 949 824 4184; fax: +1 949 824 3002. ∗∗ Corresponding author. E-mail addresses: cschen@uci.edu (C. Chen), dongqi@bnu.edu.cn (Q. Dong). and females to process native languages. But less is known 38 about the sex differences in the neural substrates underlying the 39 learning of a new language. 40 In addition to the group differences between the two sexes, 41 there are pronounced individual variations within each sex 42 (Tzourio-Mazoyer, Josse, Crivello, & Mazoyer, 2004; Xiong, 43 Rao, Gao, Woldorff, & Fox, 1998), particularly when process- 44 ing a nonfluent or new language (Dehaene et al., 1997; Xue, 45 Chen, Jin, & Dong, 2006a). For example, in a passive-viewing 46 task, Xue et al. (2006a) found that, despite the consistent leftward 47 fusiform activation in the processing of subjects’ native language 48 (i.e., Chinese), there was significant variance in fusiform asym- 49 metry (from strong right-dominance to strong left-dominance) 50 in the processing of visually matched, novel characters (i.e., 51 Korean Hangul). This finding suggests that not all subjects show 52 left-hemisphere dominance when processing visual words in a 53 new language. Xue et al. further found that individuals who 54 showed more left-lateralized fusiform activation were able to 55 learn the new script or writing system more efficiently than 56 1 0028-3932/$ – see front matter © 2006 Elsevier Ltd. All rights reserved. 2 doi:10.1016/j.neuropsychologia.2006.08.018 Please cite this article as: Chuansheng Chen et al., Sex determines the neurofunctional predictors of visual word learning, Neuropsychologia (2006), doi:10.1016/j.neuropsychologia.2006.08.018