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Posted ContentDOI

Rapid changes in brain activity during learning of grapheme-phoneme associations in adults

TL;DR: Dynamic changes in brain responses related to multi-sensory processing when grapheme-phoneme associations were learned and changes were observed in the brain responses to the novel letters during the learning process are found.
Abstract: Learning to associate written letters with speech sounds is crucial for the initial phase of acquiring reading skills. However, little is known about the cortical reorganization for supporting letter-speech sound learning, particularly the brain dynamics during the learning of grapheme-phoneme associations. In the present study, we trained 30 Finnish participants (mean age: 24.33 years, SD: 3.50 years) to associate novel foreign letters with familiar Finnish speech sounds on two consecutive days (first day ~ 50 minutes; second day ~ 25 minutes), while neural activity was measured using magnetoencephalography (MEG). Two sets of audiovisual stimuli were used for the training in which the grapheme-phoneme association in one set (Learnable) could be learned based on the different learning cues provided, but not in the other set (Control). The learning progress was tracked at a trial-by-trial basis and used to segment different learning stages for the MEG source analysis. The learning-related changes were examined by comparing the brain responses to Learnable and Control uni/multi-sensory stimuli, as well as the brain responses to learning cues at different learning stages over the two days. We found dynamic changes in brain responses related to multi-sensory processing when grapheme-phoneme associations were learned. Further, changes were observed in the brain responses to the novel letters during the learning process. We also found that some of these learning effects were observed only after memory consolidation the following day. Overall, the learning process modulated the activity in a large network of brain regions, including the superior temporal cortex and the dorsal (parietal) pathway. Most interestingly, middle- and inferior- temporal regions were engaged during multi-sensory memory encoding after the cross-modal relationship was extracted from the learning cues. Our findings highlight the brain dynamics and plasticity related to the learning of letter-speech sound associations and provide a more refined model of grapheme-phoneme learning in reading acquisition.
Citations
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01 Jan 2016
TL;DR: This is an introduction to the event related potential technique, which can help people facing with some malicious bugs inside their laptop to read a good book with a cup of tea in the afternoon.
Abstract: Thank you for downloading an introduction to the event related potential technique. Maybe you have knowledge that, people have look hundreds times for their favorite readings like this an introduction to the event related potential technique, but end up in malicious downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they are facing with some malicious bugs inside their laptop.

2,445 citations

Journal ArticleDOI
TL;DR: In 2012, I left radiology residency to pursue internal medicine training, and as a medical student, I was drawn to radiology’s diagnostic challenges and its attention to detail, but it wasn’t long after beginning radiology training that I realized I missed treating patients.
Abstract: In 2012, I left radiology residency to pursue internal medicine training As a medical student, I had been drawn to radiology’s diagnostic challenges and its attention to detail But it wasn’t long after beginning radiology training that I realized I missed treating patients When I broke news of my decision to leave, my colleagues were skeptical: after more than a year away from clinical medicine, was I sure I wanted to do this? Nevertheless, my first morning back as a senior medical resident went well I had spent the night before excitedly reading about the patients I’d be caring for Morning rounds felt at once novel and suddenly familiar—the easy cadence of conversation as our team walked down the hospital corridor; the expectant look on patients’ faces as we entered their rooms Around early evening, after my attending (and, it seemed, everyone else in the hospital) had left for the day, doubt crept in Less than 3 weeks prior, I had been comfortably reading X-rays and CTs Now I was on call and supervising two newly minted interns My pager beeped interminably Sure, I could interpret a stat portable chest radiograph…but a 12-lead EKG in a patient with atypical chest pain? Or an arterial blood gas? Before, from the relative isolation of a leather office chair and a darkened room, I had a faint sense of what it meant to be a clinician This—being a medical resident on call—was something else entirely I thought of the final lines of Sinclair Lewis’ Arrowsmith, which so ably captured that feeling that all physicians, facing a seemingly insurmountable body of knowledge, must know well: I feel as if I were really beginning to work now In that moment, however, Lewis’ words took on an ominous tone Mr H was my first admission that night He had come to the emergency room because over the preceding few months, he had noticed a steady decline in his exercise tolerance He had always been active (he was a roofer by trade), but now, walking more than a block required him to pause and hunch over, hands on his knees, to catch his breath Mr H hadn’t seen a doctor since he was in the military Hadn’t had to, he said “I’ve always been healthy” The ability to discern “sick” from “not sick,” I had heard so many times, is among the more valuable things that one learns during internship and residency In the case of Mr H, however, he didn’t look sick—not in the way that I had grown accustomed to seeing: on a stretcher, being wheeled into the scanner for a trauma survey Instead, he sat upright and proudly recounted how he had never smoked a day in his life, and how last year he and his wife had joined a gym But Mr H’s placid exterior belied ominous findings—namely, his oxygen saturation, which was 93 % at rest and dropped to below 80 % when I walked with him up and down the corridor Breathing heavily, he steadied himself against the wall about ten feet from his room He looked scared If there had been any doubt about whether Mr H was sick, it had since evaporated I pored over the chest X-ray he had received in the ED Was that a nodule? Were those reticular markings at the bases? I agonized over what to do next The list of possible diagnostic tests seemed endless I finally settled on a CT, convincing myself that if Mr H had something catastrophic in his chest, a CT would surely pick it up By the time Mr H received his scan, it was well past midnight I scrolled through the images, afraid of what the next slice would reveal My mind raced through the possibilities Sarcoid Interstitial lung disease Lymphoma Finally, after what seemed like an eternity staring at the screen (and after calling the nighthawk radiologist for reassurance), I sat back in my chair and rubbed my eyes Nothing His scan was clean It was late Rounds were in a few hours I walked back into Mr H’s room to give him the results of his CT “Well, Doc?” he asked with a wan smile He hadn’t slept I froze, struggling to find a way to tell him that about a thousand dollars and 20 millisieverts of radiation later, I was no closer to figuring out what was wrong I mumbled something about waiting on more results and left his room His gaze trailed after me In the hall, I steadied myself against the same wall that Mr H had leaned on hours earlier The next few days would reveal that he suffered from pulmonary arterial hypertension He received an echocardiogram and underwent right heart catheterization His disease was pretty advanced I kept telling myself that his was an illness that no conventional radiologic study could reliably detect, and that another resident would have done the same thing overnight But truthfully, during those next few days, I was in a fog While the pulmonologists exchanged terms like “endothelin” and “nitric oxide,” I perseverated on the events of the night I met Mr H, replaying them in a continuous loop: my less-than-thorough social history (had I asked about pet birds?), my (no doubt incomplete) physical exam I had re-entered medical residency with rusty clinical skills, to be sure; but I thought this deficit might be counterbalanced by my ability to read images Yet, had my reliance on this ability caused me to overlook Mr H’s diagnosis? When I was a radiology resident, my attendings would sometimes tell me that becoming adept at interpreting images required learning how to read all over again For instance, when looking at a chest X-ray, forget what you learned in medical school—ie, “A is for airway, B is for bones”—instead, look at the study as a whole The scan comprises a map, or better yet, words on a page; it’s up to you to glean their meaning Now, as I approach the end of internal medicine residency, I know that the same can be said of patients, their stories, their faces Looking back, I think I know why: to acquire that sine qua non characteristic that the best medicine doctors possess—the ability to elicit a patient’s history and arrive at a diagnosis—one has to learn to read patients with the same level of nuance The etiology of patients’ illnesses can be found in poring through their images, but it’s also buried in their histories and etched in their expressions Now and then I’ll hear a bit about how Mr H is doing He wears continuous oxygen The word “transplant” is frequently mentioned Hearing these updates always grounds me, reminds me how far I’ve come since that night—and also how far there is to go It’s all part of learning to read

137 citations

18 Jun 2006
TL;DR: The present event-related fMRI study was designed to address two questions that could not directly be addressed in the previous studies, due to their passive nature and blocked design: whether the enhancement/suppression of auditory cortex are truly multisensory integration effects or can be explained by different attention levels during congruent/incongruent blocks.
Abstract: In alphabetic scripts, letters and speech sounds are the basic elements of correspondence between spoken and written language. In two previous fMRI studies using blocked stimulus presentation and passive perception, we found a cross-modal modulation of the response to speech sounds in the auditory association cortex by letters, expressed as response enhancement by congruent letters and suppression by incongruent letters. Interestingly, temporal proximity was critical for this congruency effect to occur. In the present study, we used fMRI to investigate the effect of stimulus presentation mode (blocked vs. event-related) and task instruction (passive perception vs. active matching) on the neural integration of letters and speech sounds. The principle findings are 1) a replication of the previous results on passive integration using event-related fMRI, and 2) the absence of the effects of congruency and temporal proximity in the auditory association cortex during active matching. Finding 1 shows the suitability of event-related fMRI for studying letter-sound integration. Finding 2 indicates that the task demands overruled the automatic multisensory responses to letters and speech sounds, most likely because the task changed the behavioral relevance of the stimuli.

107 citations

Posted ContentDOI
01 Jun 2020-bioRxiv
TL;DR: Both script-universal and script-specific neurofunctional substrates of print-sound integration as well as their processing- and region-dependent associations with reading abilities in typical Chinese children are revealed.
Abstract: Efficient integration of grapheme and phoneme is crucial for reading development in alphabetic languages, and superior temporal cortex (STC) has been demonstrated to be the most critical region for this process. To determine whether a similar neural mechanism underlies such processing in non-alphabetic languages, and to explore its relationship with reading, we conducted a functional magnetic resonance imaging study in typically developing Chinese children. Highly frequent pictographic characters and pinyin, a transparent alphabetic coding system that assists individuals to learn the pronunciation of new characters were investigated. In support of the orthographic depth hypothesis developed in alphabetic languages, reverse congruency effect (i.e., higher activation in incongruent condition compared to congruent condition) was identified in the left inferior frontal gyrus (IFG) and bilateral STC for character (deep orthography) conditions. Furthermore, correlation analysis revealed that the congruency contrast in the left IFG was associated with proficiency in reading comprehension and morphological awareness, suggesting reading-related semantic access during the implicit integration of multisensory information regarding characters. For pinyin (shallow orthography) conditions, while no regions showed a significant congruency effect at the group level in either direction, the congruency contrast in the left superior temporal gyrus was positively correlated with oral reading performance. This observation is consistent with findings in transparent scripts on reading disorders. Taken together, these results support and generalize the orthographic depth hypothesis to a logographic language, highlight the role of the left IFG in character-syllable integration, and underscore the role pinyin could play in developing fluent reading in Chinese children. Highlights The left IFG and bilateral STC are involved in audiovisual integration of characters. The congruency contrast in the left IFG in response to characters corresponds to semantic access. The congruency contrast in the left STG in response to pinyin is correlated with print-to-sound mapping. These findings support the orthographic depth hypothesis in a nonalphabetic language. The results imply a close link between pinyin and Chinese reading acquisition.

5 citations

References
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Journal ArticleDOI
TL;DR: In this paper, a different approach to problems of multiple significance testing is presented, which calls for controlling the expected proportion of falsely rejected hypotheses -the false discovery rate, which is equivalent to the FWER when all hypotheses are true but is smaller otherwise.
Abstract: SUMMARY The common approach to the multiplicity problem calls for controlling the familywise error rate (FWER). This approach, though, has faults, and we point out a few. A different approach to problems of multiple significance testing is presented. It calls for controlling the expected proportion of falsely rejected hypotheses -the false discovery rate. This error rate is equivalent to the FWER when all hypotheses are true but is smaller otherwise. Therefore, in problems where the control of the false discovery rate rather than that of the FWER is desired, there is potential for a gain in power. A simple sequential Bonferronitype procedure is proved to control the false discovery rate for independent test statistics, and a simulation study shows that the gain in power is substantial. The use of the new procedure and the appropriateness of the criterion are illustrated with examples.

83,420 citations

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TL;DR: An automated labeling system for subdividing the human cerebral cortex into standard gyral-based neuroanatomical regions is both anatomically valid and reliable and may be useful for both morphometric and functional studies of the cerebral cortex.

9,940 citations

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TL;DR: This paper forms a null hypothesis and shows that the nonparametric test controls the false alarm rate under this null hypothesis, enabling neuroscientists to construct their own statistical test, maximizing the sensitivity to the expected effect.

6,502 citations


"Rapid changes in brain activity dur..." refers methods in this paper

  • ...…learning effects related to unisensory processing and multisensory interaction, spatiotemporal cluster-based permutation tests (Maris and Oostenveld 2007) were used for comparing Learnable and Control auditory, visual, and audiovisual interaction brain activations from the linear…...

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Journal ArticleDOI
TL;DR: Using maximum entropy approximations of differential entropy, a family of new contrast (objective) functions for ICA enable both the estimation of the whole decomposition by minimizing mutual information, and estimation of individual independent components as projection pursuit directions.
Abstract: Independent component analysis (ICA) is a statistical method for transforming an observed multidimensional random vector into components that are statistically as independent from each other as possible. We use a combination of two different approaches for linear ICA: Comon's information theoretic approach and the projection pursuit approach. Using maximum entropy approximations of differential entropy, we introduce a family of new contrast functions for ICA. These contrast functions enable both the estimation of the whole decomposition by minimizing mutual information, and estimation of individual independent components as projection pursuit directions. The statistical properties of the estimators based on such contrast functions are analyzed under the assumption of the linear mixture model, and it is shown how to choose contrast functions that are robust and/or of minimum variance. Finally, we introduce simple fixed-point algorithms for practical optimization of the contrast functions.

6,144 citations


"Rapid changes in brain activity dur..." refers methods in this paper

  • ...Fast ICA (Hyvärinen 1999) was then used to remove eye movement-related and cardiac artifacts....

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  • ...Fast ICA (Hyv€arinen, 1999) was then used to remove eye movement-related and cardiac artifacts....

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  • ...After applying ICA, data were segmented into epochs with 150 ms before and 1000 ms after stimulus onset....

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Journal ArticleDOI
TL;DR: The account presented here suggests that memories are first stored via synaptic changes in the hippocampal system, that these changes support reinstatement of recent memories in the neocortex, that neocortical synapses change a little on each reinstatement, and that remote memory is based on accumulated neocorticals changes.
Abstract: Damage to the hippocampal system disrupts recent memory but leaves remote memory intact. The account presented here suggests that memories are first stored via synaptic changes in the hippocampal system, that these changes support reinstatement of recent memories in the neocortex, that neocortical synapses change a little on each reinstatement, and that remote memory is based on accumulated neocortical changes. Models that learn via changes to connections help explain this organization. These models discover the structure in ensembles of items if learning of each item is gradual and interleaved with learning about other items. This suggests that the neocortex learns slowly to discover the structure in ensembles of experiences. The hippocampal system permits rapid learning of new items without disrupting this structure, and reinstatement of new memories interleaves them with others to integrate them into structured neocortical memory systems.

4,288 citations


"Rapid changes in brain activity dur..." refers background in this paper

  • ...Complementary learning systems have been shown in the medial-temporal systems (hippocampus and parahippocampal cortex) and neocortex, and a division of labor with the initial rapid learning in the hippocampus and gradual memory consolidation in the neocortical systems (McClelland et al., 1995; Davis et al., 2009)....

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  • ...…learning systems have been shown in the medial-temporal systems (hippocampus and parahippocampal cortex) and neocortex, and a division of labor with the initial rapid learning in the hippocampus and gradual memory consolidation in the neocortical systems (McClelland et al. 1995; Davis et al. 2009)....

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