Transitive Reasoning and Developmental Changes in Parietal Cortex Cristián Modroño (cmodrono@ull.edu.es) Department of Physiology, University of La Laguna Santa Cruz de Tenerife, 38071, Spain Gorka Navarrete (gorkang@gmail.com) Department of Psychology, Universidad Diego Portales, UDP-INECO Foundation Core on Neuroscience (UIFCoN), Santiago 8320000, Chile Antoinette Nicolle (antoinette.nicolle@gmail.com) Department of Psychology, University of Hull Hull, HU6 7RX, UK José Luis González-Mora (jlgonzal@ull.edu.es) Department of Physiology, University of La Laguna Santa Cruz de Tenerife, 38071, Spain Kathleen W. Smith (kws@yorku.ca) Department of Psychology, York University Toronto, Ont., Canada M3J 1P3 Vinod Goel1,2 (vgoel@yorku.ca) 1 Department of Psychology, York University Toronto, Ont., Canada M3J 1P3 2 IRCCS Fondazione Ospedale San Camillo, Italy Abstract braver than Celia). A number of neuroimaging studies, and at least one patient study indicate that the parietal lobes, in This study utilizes voxel-based morphometry to examine the neural basis of developmental changes in transitive reasoning particular Brodmann area 7 (BA7) and Brodmann area 40 in parietal regions. Two groups of participants (young (BA40), play a critical role in transitive inference in adult adolescents and adults) performed a transitive reasoning task, populations (Goel, 2007; Goel & Dolan, 2001; Goel, subsequent to undergoing anatomical MRI brain scans. Makale, & Grafman, 2004; Prado, Chadha, & Booth, 2011; Behaviorally, adults performed better on the transitive Waechter, Goel, Raymont, Kruger, & Grafman, 2013). reasoning task than the young adolescents. Grey matter We undertook a Voxel-Based Morphometry (VBM) study analysis of their brains showed the expected thinning/pruning of grey matter in BA 7 and a significantly greater correlation to track developmental changes in grey matter density in between the performance of the adults and grey matter density parietal cortex and its correlation with performance in than the performance of adolescents and grey matter density transitive reasoning tasks in adolescent and adult in this area. These results support the idea that developmental populations. Based upon previous research on relational anatomical changes in parietal cortex facilitate developmental reasoning in the developmental literature (Ferrer, et al., changes in transitive reasoning. 2009), we expected to find improved performance in Keywords: transitive reasoning; VBM; parietal cortex; transitive inference in the adult group. Given the consistent development activation of parietal cortex reported in a number of imaging studies on transitive reasoning (see above), we expected that Introduction the behavioural changes would be associated with Relational reasoning is the ability to consider and neuroanatomical changes in BA 7 and BA 40. manipulate relationships between multiple mental representations, and has been shown to improve throughout Methods childhood and adolescence (Ferrer, O'Hare, & Bunge, 2009). One important manifestation of relational reasoning Participants is transitive inference, that is, the process of examining and Two groups of participants took part in the experiment. The comparing a number of relational pairs in order to first group consisted of young adolescents with an age range understand overall group hierarchy (e.g. Ralph is braver of 11 years and 2 months to 16 years (N=35, 18 male, 17 than Celia, Tim is braver than Ralph; therefore Tim is female). The second group consisted of adults with an age 376 range of 20 years and 1 months to 24 years and 4 months (N=41, 22 male, 19 female). Stimuli Twenty three-term relational arguments were generated (e.g. premise1: ‘the stapler is inside the drawer’; premise 2: ‘the staples are inside the stapler’; conclusion: ‘the staples are inside the drawer’). Arguments were presented randomly on a computer screen. The beginning of every trial was signaled by a fixation cross in the middle of the screen. The sentences appeared on the screen one at a time with the first sentence appearing at 1 s, the second at 4 s, and the last sentence at 7 s. All sentences remained on the screen until the end of the trial. Subjects had 24 s after the presentation of the third sentence to respond. The response button triggered the following trial. Task Subjects were required to determine whether the given Figure 1. In white, the regions of interest used in this study conclusion followed logically from the premises (i.e. whether the argument was valid). Subjects responded ‘yes’ or ‘no’ by pressing a key on a computer keypad after the appearance of the last sentence. Subjects reviewed example Results stimuli prior to the start of the task to ensure that they understood it. Behavioural An independent samples t-test showed that transitive MRI Acquisition and Analysis reasoning scores were significantly higher for the adults (M High resolution sagittally oriented whole brain T1-weighted = .85, SD = .11) than for the young adolescents (M = .76, images were collected using a 3 Tesla GE-Medical System SD = .13), t(74) = -3.316, p = . 001). MRI scanner. A 3D fast spoiled-gradient-recalled pulse sequence was acquired (TR=8.7 msec, TE=1.7 msec, flip Neural angle=12º, matrix size=250×250 pixels, 0.976×0.976 mm in Analyses were restricted to the pre-identified regions of plane resolution, spacing between slices=1 mm, slice interest (Figure 1). LBA7 and RBA7 showed significantly thickness=1mm). lower grey matter density in the adult group compared to the The structural MRIs were preprocessed and analysed adolescent group. Subsequent ROI analysis (Table 1) using Statistical Parametric Mapping software in showed a significant interaction between age (adults > Matlab2013a (SPM12b; Wellcome Trust Centre for young adolescents) and transitive reasoning in RBA7. A Neuroimaging at UCL). The images were segmented and trend towards significance for this interaction was also normalised to MNI space using Dartel nonlinear found in LBA7. registration. The spatially normalised grey matter images were then smoothed with a Gaussian kernel of 8mm full Table 1. ROI analysis (contrasts and p-values; Bonferroni width at half maximum and then taken forward to a SPM corrected for multiple comparisons) group analysis. Statistical analyses were performed using a Contrasts Superior Superior Supra- Supra- full factorial design investigating the interaction between parietal parietal marginal marginal the factor age group and the covariate transitive reasoning. (LBA7) (RBA7) gyrus gyrus Gender and total intracranial volume were also included as (LBA40) (RBA40) regressors of no interest in order to reduce variance GM young .012 .006 .228 .423 unrelated to the transitive reasoning variable of interest. > After specifying the SPM model, we used the MarsBar GM adults toolbox (Brett et al, 2002) for region of interest (ROI) Interaction: .084 .050 1 1 analysis. This way, differences in grey matter density age group x between age groups, and interactions between age group and reasoning reasoning, were tested in four anatomical ROIs: two regions (adults placed in the superior parietal cortex (LBA7, RBA7) and > young two regions placed in the inferior parietal cortex, adolescents) comprising the supramarginal gyri (LBA40 and RBA40; see Figure 1). 377 Discussion development during childhood and adolescence: a longitudinal MRI study. Nature Neuroscience, 2(10), 861- The present Voxel-Based Morphometry work studies the 863. neural correlates of developmental change in transitive Goel, V. (2007). Anatomy of deductive reasoning. Trends in reasoning. At the behavioural level we found that adults Cognitive Sciences, 11(10), 435-441. performed better in the transitive inference task than the Goel, V., & Dolan, R. J. (2001). Functional neuroanatomy young adolescents. This result is consistent with previous of three-term relational reasoning. Neuropsychologia, studies with other relational reasoning tasks, e.g. the 39(9), 901-909. Raven’s progressive matrices task (Crone et al., 2009). Goel, V., Makale, M., & Grafman, J. (2004). The At the neural level we found less grey matter density in hippocampal system mediates logical reasoning about the adults than in the young adolescents in the left BA7 and familiar spatial environments. Journal of Cognitive the right BA7. Decrease in grey matter after puberty is a Neuroscience, 16(4), 654-664. known issue, and it has been attributed to synaptic pruning Prado, J., Chadha, A., & Booth, J. R. (2011). The Brain (Giedd et al., 1999). More interestingly, the ROI analysis Network for Deductive Reasoning: A Quantitative Meta- showed a significant interaction between age group and analysis of 28 Neuroimaging Studies. Journal of transitive reasoning in right BA7, meaning that improved Cognitive Neuroscience, 23(11), 3483-3497. performance in the reasoning task was more related to grey Waechter, R. L., Goel, V., Raymont, V., Kruger, F., & matter density in the adults than in the young adolescents. A Grafman, J. (2013). Transitive inference reasoning is trend to significance was also present for the same impaired by focal lesions in parietal cortex rather than interaction in the left BA7, but we did not find any rostrolateral prefrontal cortex. Neuropsychologia, 51(3), significant result in BA40. This may be related with a lack 464-471. of statistical power that perhaps could be overcome by using a larger sample size. Another possible explanation is that the developmental changes that happen in BA40 have a different timing than those that happen in BA7. Taken together, these results support the idea that during development, regions in the parietal cortex are pruned and fine-tuned, resulting in greater efficiency. The structural brain changes lead to improved performance in transitive reasoning. Acknowledgments We acknowledge the support of Servicio de Resonancia Magnética para Investigaciones Biomédicas de la Universidad de La Laguna. We also acknowledge the support of La Brújula Educativa. We thank our volunteers for their participation in this study. This research was supported in part by grants from the Wellcome Trust (#089233) and NSERC to Vinod Goel. Financial support was also provided by the following Spanish National Program: Ministerio de Ciencia e Innovación (PTA2011- 4995-I). References Brett, M., Anton J., Valabregue, R., & Poline, J. (2002, june). Region of interest analysis using an SPM toolbox. Paper presented at the 8th International Conference on Functional Mapping of the Human Brain, Sendai, Japan. Crone, E. 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