Advances in Cognitive Sciences

fa پردازش شنیداری جمله و پلنیوم‌گیجگاهی: شواهدی از تصویربرداری تشدید مغناطیسی عملکردی در دوزبانه‌ها The auditory sentence processing and the planum temporale: Evidence from functional magnetic resonance mapping in bilinguals فلسفه ذهن و زبان شناسی شناختی پژوهشي اصیل Research <div style="text-align: justify;">مقدمه: پژوهش حاضر با هدف بررسی نقش ناحیه پلنیوم‌گیجگاهی چپ و راست در پردازش شنیداری جملات زبان اول و دوم در افراد دوزبانه اجرا شد. روش کار: جامعه آماری پژوهش حاضر، دانشجویان دوزبانه ترکی_فارسی شهر تهران در سال 1398 بود. داده‌های 36 فرد دوزبانه که به روش هدفمند انتخاب شده بودند، در حین اجرای یک تکلیف شنیداری دوزبانه به روش تصویربرداری تشدید مغناطیسی کارکردی (fMRI) اخذ شد. به منظور شناسایی الگوی فعالیت محرک‌های دستوری_نادستوری زبان اول و دوم در ناحیه پلنیوم‌گیجگاهی، آنالیزی بر مبنای ناحیه مطلوب (ROI-based) در نرم‌افزار FSL اجرا شد و درصد تغییر سیگنال به عنوان معیار «شدت» برای هر شرکت‌کننده استخراج و در نرم‌افزار SPSS نسخه 26 تجزیه و تحلیل آماری شد. یافته‌ها: اگرچه معناداری اثر دستوری‌بودگی برای هر دو زبان اول و دوم در پلنیوم‌گیجگاهی چپ و راست مشاهده شد (0/001>P)، برانگیختگی پلنیوم‌گیجگاهی چپ بیشتر بود. افزون بر این، پاسخ مغزی بزرگتر به جملات نادستوری زبان اول در مقایسه با جملات نادستوری زبان دوم در پلنیوم‌گیجگاهی چپ محرز شد. نتیجه‌گیری: هم‌پوشانی همبسته‌های نورونی دو زبان در پلنیوم‌گیجگاهی، به عنوان یک واسط محاسباتی، سطح بالای بسندگی دوزبانه‌های حاضر به زبان دومشان را که در سن 7 سالگی آموخته بودند، تأیید می‌کند. پلنیوم‌گیجگاهی چپ نقش برجسته‌تری در پردازش شنیداری جملات در افراد دوزبانه دارد که ممکن است دال بر یکسویه‌شدگی این ناحیه باشد. فعالیت بیشتر زبان اول نسبت به زبان دوم در پلنیوم‌گیجگاهی چپ، حاکی از این است که در حالت دوزبانه و در شرایطی که فرد دوزبانه به هر دو زبان اول و دوم خود به یک میزان مسلط است، زبان اول به عنوان زبان پایه عمل می‌کند که مستلزم صرف زمان و منابع شناختی بیشتر برای مهار و فعال‌سازی مجدد این زبان است.  </div> Introduction To our knowledge, no study has yet used the auditory paradigm to investigate PT activation during L1-L2 sentence processing. Employing this experimental design is critical to our understanding of target/non-target language activation. Moreover, research in this area has mainly been limited to the neuroanatomical or pathological studies with little attention to bilinguals. Consequently, the extent to which the bilateral PTs are activated during simultaneous L1-L2 processing needs to be clarified. The present study aims to explore these critical issues. To address this study’s goal, the discussion critical revolve around the following questions: Q1. Do the left and right PT act differently for the auditory sentence processing? Q2. Are L1 and L2 processed differently in the PL? Methods This study recruited healthy and young bilingual adults through social media via advertisements on top universities in Tehran, Iran. In total, forty-one subjects participated in the experiment. Five subjects were excluded due to technical problems. The final sample consisted of thirty-six (21 female, all right-handed). All participants were native speakers of Turkish who had learned Persian as L2 at the age of seven when entering school. Participants underwent an fMRI scan and completed an auditory grammaticality judgment task in the scanner. During the 21.5-min fMRI scan, participants were required to judge each sentence for grammatical correctness by pressing the button of a left (ungrammatical) or right (grammatical) response grip with the thumb while minimizing head movements. The task included four alternating rest and auditory sentence blocks. Each auditory sentence block had 32 runs and was bookended by 30-second rest periods where no stimuli were presented, allowing for hemodynamic baseline data collection. Correct and violated sentences were randomly intermixed within each block, but language blocks alternated in a fixed sequence. In total, 128 spoken sentences (50% in L1 and 50% in L2, with 50% violation per language) were used to assess syntactic processing in bilinguals. Images were acquired with a Siemens Prisma 3-Tesla scanner at NBML. The fMRI images were collected using an echo-planar imaging (EPI) sequence with a 20-channel head coil consisting of 430 volumes and 45 axial slices per volume (repetition time (TR)=3000 ms, echo time (TE)=30 ms, flip angle=90◦, matrix size=64×64, slice thickness=3 mm, field of view (FOV)=192 mm2, voxel size=3×3×3 mm3). Moreover, the high-resolution T1-weighted structural images were collected through a magnetization-prepared rapid gradient-echo (MPRAGE) sequence (TR=1800 ms, TE=3.53 ms, flip angle=7◦, matrix size=256×256, slice thickness=1 mm, FOV=256 mm2, voxel size=1×1×1 mm3, duration=5-min). The anatomical MPRAGE volumes were pre-processed following the brain extraction and used as anatomical references in the functional image processing co-registration steps using FEAT in FSL. The fMRI analyses were performed according to a standard pipeline comprising the following steps: motion correction and realignment, slice-timing correction, segmentation and normalization to the standard MNI template and spatial smoothing (6 mm full-width at half-maximum isotropic Gaussian), temporal filtering (with sigma=50.0 s), and exploratory ICA-based data analysis. The general linear model (GLM) was used to construct the statistical model on the BOLD response to perform the first-level analysis. Z (Gaussianised T/F) statistic images were thresholded using clusters determined by Z>3.1 and a (corrected) cluster significance threshold of P<0.05. A whole-brain analysis was performed to detect the mechanisms underlying syntactic processing in the bilateral PT. Then, PSC was extracted as an intensity measure in this region per participant according to the Harvard-Oxford Atlas implemented in FSL. All statistical analyses were conducted in IBM SPSS Statistics V26. Results Whole-Brain Results of Brain Activation Figure 1A visualizes the location of the PT. Figure 1B exhibits the patterns of whole-brain activation during the presentation of corrected and violated stimuli in L1 and L2 for each hemisphere. Greater left-hemispheric activation is detectable for the region of the PT (white circles) when comparing the left and right columns. ROI-based Results The results are depicted in Figure 2. The main factor of Grammaticality yielded a significant effect (F (1, 35)=53.296, P<0.001, <m:omath><m:ssubsup><m:ssubsuppr><m:ctrlpr></m:ctrlpr></m:ssubsuppr><m:e><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>ƞ</m:r></m:e><m:sub><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>p</m:r></m:sub><m:sup><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>2</m:r></m:sup></m:ssubsup></m:omath> =0.618), with a more significant effect for grammatical (3.712 PSC) as compared to ungrammatical stimuli (3.303 PSC). Furthermore, a significant main effect of the Hemisphere (F (1, 35)=25.451, P<0.001, <m:omath><m:ssubsup><m:ssubsuppr><m:ctrlpr></m:ctrlpr></m:ssubsuppr><m:e><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>ƞ</m:r></m:e><m:sub><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>p</m:r></m:sub><m:sup><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>2</m:r></m:sup></m:ssubsup></m:omath> =0.435), indicating that the left hemisphere (4.014) generated stronger PSC as compared to the right hemisphere (3.000). A significant Grammaticality×Hemisphere interaction (F (1, 35)=16.449, P=0.001, <m:omath><m:ssubsup><m:ssubsuppr><m:ctrlpr></m:ctrlpr></m:ssubsuppr><m:e><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>ƞ</m:r></m:e><m:sub><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>p</m:r></m:sub><m:sup><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>2</m:r></m:sup></m:ssubsup></m:omath> =0.333) indicated that the left hemisphere triggered a more significant effect for L1 stimuli (4.113) than for L2 stimuli (3.916) (t (35)=3.517, P=0.001), whereas in the right hemisphere there were no differences between L1 (2.970) and L2 (3.030) sentences (t (35)=-1.176, P=0.248).  Finally, the Grammaticality×Language×Hemisphere interaction (F (1, 35)=7.961, P=0.008, <m:omath><m:ssubsup><m:ssubsuppr><m:ctrlpr></m:ctrlpr></m:ssubsuppr><m:e><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>ƞ</m:r></m:e><m:sub><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>p</m:r></m:sub><m:sup><m:r><m:rpr><m:scr m:val="roman"><m:sty m:val="p"></m:sty></m:scr></m:rpr>2</m:r></m:sup></m:ssubsup></m:omath> =0.194) turned out to be significant. The analysis by the grammaticality factor showed that in the left hemisphere, L1-grammatical stimuli (4.244) engendered a larger effect than L1-ungrammatical stimuli (3.866) (t (35)=2.980, P=0.005). Similarly, L2-grammatical stimuli (4.161) engendered a larger effect than L2-ungrammatical stimuli (3.672) (t (35)=5.311, P<0.001). In the right hemisphere, L1-grammatical stimuli (3.204) engendered a larger effect than L1-ungrammatical stimuli (2.737) (t (35)=5.363, P<0.001). Similarly, L2-grammatical stimuli (3.214) engendered a larger effect than L2-ungrammatical stimuli (2.845) (t (35)=5.572, P<0.001). The analysis by language factor revealed that in left-hemispheric grammatical stimuli no differences were obtained for L1 (4.271) and L2 (4.161) sentences (t (35)=1.352, P=0.185), nor in the right-hemispheric grammatical stimuli for L1 (3.204) and L2 (3.214) sentences (t (35)=-0.132, P=0.896). In left-hemispheric ungrammatical stimuli, L1 stimuli (3.956) engendered a larger effect than L2 stimuli (3.672) (t (35)=3.326, P=0.002), whereas in the right-hemispheric ungrammatical stimuli, there were no differences between L1 (2.736) and L2 (2.845) sentences (t (35)=-1.889, P=0.067). The analysis by the hemisphere factor exhibited that in L1-grammatical stimuli, the left hemisphere (4.271) triggered a more significant effect than the right hemisphere (3.204) (t (35)=4.505, P<0.001). Similarly, in L2-grammatical stimuli, the left hemisphere (4.161) triggered a more significant effect than the right hemisphere (3.214) (t (35)=4.435, P<0.001). In L1-ungrammatical stimuli, the left hemisphere (3.956) triggered a more significant effect than the right hemisphere (2.737) (t (35)=5.573, P<0.001). Similarly, in L2-ungrammatical stimuli, the left hemisphere (3.672) triggered a more significant effect than the right hemisphere (2.845) (t (35)=4.275, P<0.001). Conclusion The current findings are essential in several ways. First, the present findings indicate a substantial overlap of the neuronal correlates for L1 and L2 in the PT, confirming our participants’ L2 high-proficiency. Second, our results support the contribution of the left PT as a computational interface in sentence processing. Third, the sensitivity of the right PT to the present auditory stimuli confirms its role in stimulus-driven auditory attention. Fourth, the higher activity of L1-ungrammatical stimuli as compared to L2-ungrammatical stimuli in the left hemisphere indicates that current bilinguals have chosen L1 (Turkish) as their base language, leading to more RT switch cost for L1 than L2, as well as increased cognitive control to reactivate L1 after L2 production. Fifth, L1-L2 similarities at the sentence level can facilitate the L2 processing. Ethical Considerations Compliance with ethical guidelines The Ethics Committee of Iran University of Medical Sciences has approved the current research under the code IR.IUMS.REC.1398.465. We strictly adhered to all ethical guidelines, including clearly explaining the research objectives to participants, ensuring their freedom to join or withdraw from the study at any time, obtaining written consent, maintaining the confidentiality of participants’ information, and compensating them for their time. Authors’ contributions This article is part of the first author’s PhD dissertation at Tarbiat Modares University of Tehran. The first author conceptualized the study, collected and analyzed the data, designed the task, wrote the manuscript, and provided valuable laboratory resources. The second author contributed to the planning of the work, designed the task, and supervised data analysis. Both authors approved the submitted version. Funding The Cognitive Sciences and Technologies Council supported this study under Grant [number 7401] awarded to the first author. This research was also made possible by a doctoral dissertation grant from the Department of Linguistics, Tarbiat Modares University, a scholarship fund (PhD Visiting Scholar Program) from the Iranian Ministry of Science, Research and Technology, and a research grant from Iran High-tech Laboratory Network. Acknowledgments The authors wish to express their appreciation to the participants. Conflict of interest Authors have no conflict of interest to declare. دوزبانه‌های متوازن, پردازش شنیداری جمله, پلنیوم گیجگاهی, تصویربرداری تشدید مغناطیسی کارکردی Balanced bilinguals, Auditory sentence processing, Planum temporale, Functional magnetic resonance imaging 31 46 http://icssjournal.ir/browse.php?a_code=A-10-1705-1&slc_lang=fa&sid=1 Simin Meykadeh سیمین میکده A.meykadeh@modares.ac.ir 100319475328460017234 100319475328460017234 Yes PhD, Linguistics Department, Tarbiat Modares University, Tehran, Iran دکتری تخصصی زبان‌شناسی، دانشگاه تربیت مدرس، تهران، ایران Werner Sommer ورنر زومر 100319475328460017235 100319475328460017235 No Professor, Psychology Department, Humboldt University of Berlin, Berlin, Germany استاد روان‌شناسی، دانشگاه هومبولت برلین، برلین، آلمان