Effective brain connectivity in children with reading difficulties during phonological processing

Using Dynamic Causal Modeling (DCM) and functional magnetic resonance imaging (fMRI), we examined effective connectivity between three left hemisphere brain regions (inferior frontal gyrus, inferior parietal lobule, fusiform gyrus) and bilateral medial frontal gyrus in 12 children with reading difficulties (M age=12.4, range: 8.11-14.10) and 12 control children (M age=12.3, range: 8.9-14.11) during rhyming judgments to visually presented words. More difficult conflicting trials either had similar orthography but different phonology (e.g. pint-mint) or similar phonology but different orthography (e.g. jazz-has). Easier non-conflicting trials had similar orthography and phonology (e.g. dime-lime) or different orthography and phonology (e.g. staff-gain). The modulatory effect from left fusiform gyrus to left inferior parietal lobule was stronger in controls than in children with reading difficulties only for conflicting trials. Modulatory effects from left fusiform gyrus and left inferior parietal lobule to left inferior frontal gyrus were stronger for conflicting trials than for non-conflicting trials only in control children but not in children with reading difficulties. Modulatory effects from left inferior frontal gyrus to inferior parietal lobule, from medial frontal gyrus to left inferior parietal lobule, and from left inferior parietal lobule to medial frontal gyrus were positively correlated with reading skill only in control children. These findings suggest that children with reading difficulties have deficits in integrating orthography and phonology utilizing left inferior parietal lobule, and in engaging phonological rehearsal/segmentation utilizing left inferior frontal gyrus possibly through the indirect pathway connecting posterior to anterior language processing regions, especially when the orthographic and phonological information is conflicting.     

SUPPORT FOR A NEUROPSYCHOLOGICAL MODEL OF SPIRITUALITY IN PERSONS WITH TRAUMATIC BRAIN INJURY

Recent research suggests that spiritual experiences are related to increased physiological activity of the frontal and temporal lobes and decreased activity of the right parietal lobe. The current study determined if similar relationships exist between self‐reported spirituality and neuropsychological abilities associated with those cerebral structures for persons with traumatic brain injury (TBI). Participants included 26 adults with TBI referred for neuropsychological assessment. Measures included the Core Index of Spirituality (INSPIRIT); neuropsychological indices of cerebral structures: temporal lobes (Wechsler Memory Scale‐III), right parietal lobe (Judgment of Line Orientation), and frontal lobes (Trail Making Test, Controlled Oral Word Association Test). As hypothesized, spirituality was significantly negatively correlated with a measure of right parietal lobe functioning and positively correlated (nonsignificantly) with measures of left temporal lobe functioning. Contrary to hypotheses, correlations between spirituality and measures of frontal lobe functioning were zero or negative (and nonsignificant). The data support a neuropsychological model that proposes that spiritual experiences are related to decreased activity of the right parietal lobe, which may be associated with decreased awareness of the self (transcendence) and increased activity of the left temporal lobe, which may be associated with the experience of specific religious archetypes (religious figures and symbols).     

The functional anatomy of word comprehension and production

This review describes the functional anatomy of word comprehension and production. Data from functional neuroimaging studies of normal subjects are used to determine the distributed set of brain regions that are engaged during particular language tasks and data from studies of patients with neurological damage are used to determine which of these regions are necessary for task performance. This combination of techniques indicates that the left inferior temporal and left posterior inferior parietal cortices are required for accessing semantic knowledge; the left posterior basal temporal lobe and the left frontal operculum are required for translating semantics into phonological output and the left anterior inferior parietal cortex is required for translating orthography to phonology. Further studies are required to establish the specific functions of the different regions and how these functions interact to provide our sophisticated language system.     

Increased arithmetic complexity is associated with domain-general but not domain-specific magnitude processing in children: A simultaneous fNIRS-EEG study

The investigation of the neural underpinnings of increased arithmetic complexity in children is essential for developing educational and therapeutic approaches and might provide novel measures to assess the effects of interventions. Although a few studies in adults and children have revealed the activation of bilateral brain regions during more complex calculations, little is known about children. We investigated 24 children undergoing one-digit and two-digit multiplication tasks while simultaneously recording functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG) data. FNIRS data indicated that one-digit multiplication was associated with brain activity in the left superior parietal lobule (SPL) and intraparietal sulcus (IPS) extending to the left motor area, and two-digit multiplication was associated with activity in bilateral SPL, IPS, middle frontal gyrus (MFG), left inferior parietal lobule (IPL), and motor areas. Oscillatory EEG data indicated theta increase and alpha decrease in parieto-occipital sites for both one-digit and two-digit multiplication. The contrast of two-digit versus one-digit multiplication yielded greater activity in right MFG and greater theta increase in frontocentral sites. Activation in frontal areas and theta band data jointly indicate additional domain-general cognitive control and working memory demands for heightened arithmetic complexity in children. The similarity in parietal activation between conditions suggests that children rely on domain-specific magnitude processing not only for two-digit but—in contrast to adults—also for one-digit multiplication problem solving. We conclude that in children, increased arithmetic complexity tested in an ecologically valid setting is associated with domain-general processes but not with alteration of domain-specific magnitude processing.     

Developmental dissociation in the neural responses to simple multiplication and subtraction problems

Mastering single‐digit arithmetic during school years is commonly thought to depend upon an increasing reliance on verbally memorized facts. An alternative model, however, posits that fluency in single‐digit arithmetic might also be achieved via the increasing use of efficient calculation procedures. To test between these hypotheses, we used a cross‐sectional design to measure the neural activity associated with single‐digit subtraction and multiplication in 34 children from 2nd to 7th grade. The neural correlates of language and numerical processing were also identified in each child via localizer scans. Although multiplication and subtraction were undistinguishable in terms of behavior, we found a striking developmental dissociation in their neural correlates. First, we observed grade‐related increases of activity for multiplication, but not for subtraction, in a language‐related region of the left temporal cortex. Second, we found grade‐related increases of activity for subtraction, but not for multiplication, in a region of the right parietal cortex involved in the procedural manipulation of numerical quantities. The present results suggest that fluency in simple arithmetic in children may be achieved by both increasing reliance on verbal retrieval and by greater use of efficient quantity‐based procedures, depending on the operation.     

Association of Fine Motor Loss and Allodynia in Fibromyalgia: An fNIRS Study

Recent studies showed that fine motor control dysfunction was observed in fibromyalgia (FM) syndrome as well as allodynia. However, brain signatures of this association still remain unclear. In this study, finger tapping task (FTT) and median nerve stimulation (MNS) were applied to both hands of 15 FM patients and healthy controls (HC) to understand this relationship. Hemodynamic activity was measured simultaneously using functional near-infrared spectroscopy (fNIRS). Experiments were analyzed separately by using 2x2 repeated measures ANOVA. Results for the FTT experiment revealed that HC showed higher activity than FM patients in bilateral superior parietal gyrus (SPG), left supramarginal gyrus (SMG) and right somatosensory cortex (SI). Furthermore, right-hand FTT resulted in higher activity than left-hand FTT in left SPG, left SI and right motor cortex (MI). In the MNS experiment, FM patients showed higher activity than HC in bilateral SPG, right SMG, right SI and right middle frontal gyrus (MFG). Negative correlation was observed in left SPG between FTT and MNS activities. Besides, MNS activity in left SPG was negatively correlated with left-hand pain threshold.This study revealed that left SPG might be an important indicator to associate fine motor loss and allodynia in FM.     

发展性阅读障碍的视觉空间注意加工能力

鉴于阅读起始于基础视觉加工阶段, 越来越多的研究者开始关注阅读障碍者的视觉空间注意加工能力。视觉空间注意是指个体对视觉刺激的空间位置的注意, 可通过线索提示、视觉搜索和视觉注意广度等视觉任务来考察。大量国内外研究发现, 发展性阅读障碍者在视觉空间注意任务下表现出行为和神经活动方面的异常。其中的神经机制问题不仅反映在与视觉空间注意有关的顶叶区域激活异常, 还存在于脑区间功能连接异常(如顶叶区域与字形加工区的功能连接)。未来研究还需利用横断和追踪研究探讨阅读障碍与视觉空间注意能力发展关系的内在机制, 以及探究语言特性对阅读障碍者视觉空间注意缺陷的可能调节作用。     

认知重评和表达抑制情绪调节策略的脑网络分析：来自EEG和ERP的证据

本文旨在对认知重评和表达抑制两种常用情绪调节策略的自发脑网络特征及认知神经活动进行深入探讨。研究采集36名在校大学生的静息态和任务态脑电数据, 经过源定位和图论分析发现节点效率与两种情绪调节显著相关的脑区, 以及脑区之间的功能连接。研究结果表明, 在使用认知重评进行情绪调节时会激活前额叶皮质、前扣带回、顶叶、海马旁回和枕叶等多个脑区, 在使用表达抑制进行情绪调节时会激活前额叶皮质、顶叶、海马旁回、枕叶、颞叶和脑岛等多个脑区。因此, 这些脑区的节点效率或功能连接强度可能成为评估个体使用认知重评和表达抑制调节情绪效果的指标。     

Neural correlates of mapping from phonology to orthography in children performing an auditory spelling task

Age-related differences (9- to 15-year-olds) in the neural correlates of mapping from phonology to orthography were examined with functional magnetic resonance imaging (fMRI). Participants were asked to determine if two spoken words had the same spelling for the rime (corresponding letters after the first consonant or consonant cluster). Some of the word pairs had conflicting orthography and phonology (e.g. jazz-has, pint-mint) whereas other pairs had non-conflicting information (e.g. press-list, gate-hate) (see Table 1). There were age-related increases in activation for lexical processing (across conflicting and non-conflicting conditions) in left inferior parietal lobule, suggesting that older children have a more elaborated system for mapping between phonology and orthography that includes connections at different grain sizes (e.g. phonemes, onset-rimes, syllables). In addition, we found that the conflicting conditions had lower accuracy, slower reaction time and greater activation in left inferior frontal gyrus as compared to non-conflicting conditions. Higher accuracy was also correlated with greater activation in left inferior frontal gyrus for the most difficult conflicting condition (e.g. jazz-has). The finding of both a conflict effect and a correlation with accuracy in left inferior frontal gyrus suggests that this region may be involved in resolving the conflict between orthographic and phonological representations.     

Word and letter string processing networks in schizophrenia: evidence for anomalies and compensation

Imaging studies show that in normal language correlated activity between anterior and posterior brain regions increases as the linguistic and semantic content (i.e., from false fonts, letter strings, pseudo words, to words) of stimuli increase. In schizophrenia however, disrupted functional connectivity between frontal and posterior brain regions has been frequently reported and these disruptions may change the nature of language organization. We characterized basic linguistic operations in word and letter string processing in a region-of-interest network using structural equation modeling (SEM). Healthy volunteers and volunteers with schizophrenia performed an fMRI one-back matching task with real words and consonant letter strings. We hypothesized that left hemisphere network dysfunction in schizophrenia would be present during processes dealing with linguistic/semantic content. The modeling results suggest aberrant left hemisphere function in schizophrenia, even in tasks requiring minimal access to language. Alternative mechanisms included increases in right hemisphere involvement and increased top-down influence from frontal to posterior regions.     

The brain adapts to orthography with experience: evidence from English and Chinese

Using functional magnetic resonance imaging (fMRI), we examined the process of language specialization in the brain by comparing developmental changes in two contrastive orthographies: Chinese and English. In a visual word rhyming judgment task, we found a significant interaction between age and language in left inferior parietal lobule and left superior temporal gyrus, which was due to greater developmental increases in English than in Chinese. Moreover, we found that higher skill only in English children was correlated with greater activation in left inferior parietal lobule. These findings suggest that the regions associated with phonological processing are essential in English reading development. We also found greater developmental increases in English than in Chinese in left inferior temporal gyrus, suggesting refinement of this region for fine‐grained word form recognition. In contrast, greater developmental increases in Chinese than in English were found in right middle occipital gyrus, suggesting the importance of holistic visual‐orthographic analysis in Chinese reading acquisition. Our results suggest that the brain adapts to the special features of the orthography by engaging relevant brain regions to a greater degree over development.     

Motor and cognitive interference effects on unimanual tapping rates

Experiments conducted on both normal and disordered populations have led to the hypothesis that the left hemisphere's specialization for language results from its control over motor activities. This control is reflected in the lateralized disruption of manual activity during cerebral time-sharing tasks. Recent studies have challenged this hypothesis, stating that the interference effects reflect both cognitive and motor mechanisms in the left hemisphere. This experiment investigates whether the left hemisphere's control over speech involves both of these components or is purely motor. The question was examined by measuring the effect of concurrent hemispheric activity on single-finger tapping rates. Forty subjects tapped under two conditions: speaking and listening. The data show there may be both motor and cognitive mechanisms involved in left-hemisphere control.     

文盲与非文盲汉字字形和语音加工的脑机制

利用功能性磁共振成像(fMRI)技术探讨文盲和非文盲汉字字形和语音加工脑机制的差异。实验1使用汉字字形和图形比较了中国人文盲和非文盲字形加工过程脑机制的左侧差异。实验2使用汉字语音和纯音比较了文盲和非文盲语音加工过程脑机制的双侧差异。结果表明文盲与非文盲汉字字形和语音加工脑机制不同,且非文盲的脑活动强。     

An fMRI investigation of covertly and overtly produced mono- and multisyllabic words

Studies suggest that the left insula may play an important role in speech motor programming. We used functional magnetic resonance imaging to investigate the role of the left insula in the production of monosyllabic or multisyllabic words during overt and covert speech conditions. The left insula did not show a BOLD response for multisyllabic words (which should require more speech motor programming) that was different from that for monosyllabic words. Left parietal lobe regions showed a greater response for multisyllabic as compared to monosyllabic words. This is consistent with clinical studies showing that left parietal lobe lesions can produce a deficit in speech programming. Despite similarities, covert and overt speech did not demonstrate the same patterns of BOLD response. The BOLD response was greater during overt speech in areas that have been shown to play an important role in speech production including left premotor cortex/BA6, left primary motor cortex, left insula, and left superior temporal gyrus.     

3D mapping of language networks in clinical and pre-clinical Alzheimer's disease

We investigated the associations between Boston naming and the animal fluency tests and cortical atrophy in 19 probable AD and 5 multiple domain amnestic mild cognitive impairment patients who later converted to AD. We applied a surface-based computational anatomy technique to MRI scans of the brain and then used linear regression models to detect associations between animal fluency and Boston Naming Test (BNT) performance and cortical atrophy. The global permutation-corrected significance for the maps associating BNT performance with cortical atrophy was p=.0124 for the left and p=.0196 for the right hemisphere and for the animal fluency maps p=.055 for the left and p=.073 for the right hemisphere. The degree of language impairment correlated with cortical atrophy in the left temporal and parietal lobes (BA 20, 21, 37, 39, 40, and 7), bilateral frontal lobes (BA 8, 9, and 44) and the right temporal pole (BA 38). Using a novel 3D mapping technique, we demonstrated that in AD language abilities are strongly influenced by the integrity of the perisylvian cortical regions.     

藏汉双语者汉语阅读理解的静息态功能连接分析

研究结合静息态全脑功能连接密度和基于种子点的功能连接（FC）分析考察了藏汉双语者汉语（L2）阅读各子能力（细节捕捉和推理判断）的固有脑功能组织特点。结果发现左侧额下回—左侧颞上回和右侧舌回—右侧中央前回之间的FC值均与细节捕捉题得分和推理判断题得分呈显著正相关,但是左侧额下回—右侧顶下小叶之间的FC值只与推理判断题得分呈显著正相关。表明藏汉双语者汉语阅读各子能力之间既有重叠的又有不同的功能连接通路。     

Neural correlates of feigned memory impairment are distinguishable from answering randomly and answering incorrectly: an fMRI and behavioral study

Previous functional magnetic resonance imaging (fMRI) studies have identified activation in the prefrontal-parietal-sub-cortical circuit during feigned memory impairment when comparing with truthful telling. Here, we used fMRI to determine whether neural activity can differentiate between answering correctly, answering randomly, answering incorrectly, and feigned memory impairment. In this study, 12 healthy subjects underwent block-design fMRI while they performed digit task of forced-choice format under four conditions: answering correctly, answering randomly, answering incorrectly, and simulated feigned memory impairment. There were three main results. First, six areas, including the left prefrontal cortex, the left superior temporal lobe, the right postcentral gyrus, the right superior parietal cortex, the right superior occipital cortex, and the right putamen, were significantly modulated by condition type. Second, for some areas, including the right superior parietal cortex, the right postcentral gyrus, the right superior occipital cortex, and the right putamen, brain activity was significantly greater in feigned memory impairment than answering randomly. Third, for the areas including the left prefrontal cortex and the right putamen, brain activity was significantly greater in feigned memory impairment than answering incorrectly. In contrast, for the left superior temporal lobe, brain activity was significantly greater in answering incorrectly than feigned memory impairment. The results suggest that neural correlates of feigned memory impairment are distinguishable from answering randomly and answering incorrectly in healthy subjects.     

Language switching in the bilingual brain: What’s next?

Recent work using functional neuroimaging with early bilinguals has found little evidence for separate neural systems for each language during picture naming (Hernandez, A. E., Dapretto, M., Mazziotta, J., & Bookheimer, S. (2001). Language switching and language representation in Spanish–English bilinguals: An fMRI study. Neuroimage, 14, 510–520). However, switching between languages in early bilinguals during picture naming shows increased activity in the Dorsolateral Prefrontal Cortex (DLPFC) suggesting the importance of maintaining goal related information in order to bias subsequent response selection (Braver, T. S., Barch, D. M., Kelley, W. M., Buckner, R. L., Cohen, N. J., Miezin, F. M., et al. (2001). Direct comparison of prefrontal cortex regions engaged by working and long-term memory tasks. Neuroimage, 14, 48–59; Cohen, J. D., Braver, T. S., & O’Reilly, R. C. (1996). A computational approach to prefrontal cortex, cognitive control and schizophrenia: Recent developments and current challenges. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 351, 1515–1527; O’Reilly, R. C., Braver, T. S., & Cohen, J. D. (1999). A biologically based computational model of working memory. In E. Akira Miyake, E. Priti Shah & et al. (Eds.), Models of working memory: Mechanisms of active maintenance and executive control. (pp. 375–411): New York, NY, USA). The current study set out to test early bilinguals using a picture naming paradigm. Results revealed increased activity in the DLPFC and the superior parietal lobule during language switching compared to naming of pictures in a single language. Increased activity was also observed between early learned first and second languages. The results from single language conditions revealed differences in areas devoted to language processing such as the Superior Temporal Gyrus. However, increased activity in brain areas devoted to memory, somatosensory processing and emotion were also observed. Taken together these results replicate previous studies on language switching. They also extend studies on the neural bases of bilingualism by suggesting that early bilinguals’ representation of the two languages may be mediated by neural systems not typically associated with language. The article ends by considering future directions in understanding the brain bases of language switching and single language processing in bilinguals.     

Subgroups of autistic children based on social behavior display distinct patterns of brain activity

Two questions were addressed in the present study: (1) Do autistic and normally developing children exhibit regionally specific differences in electroencephalographic (EEG) activity? (2) Do subgroups of autistic children classified according to Wing and Gould's (1979) system which emphasizes degree of social impairment exhibit distinct patterns of EEG activity? Twenty-eight children with autism (5 to 18 years of age) and two groups of normally developing children (one matched on chronological age and the other on receptive language level) participated. EEG was recorded from left and right frontal, temporal, and parietal regions during an alert baseline condition. Compared to normally developing children, autistic children exhibited reduced EEG power in the frontal and temporal regions, but not in the parietal region. Differences were more prominent in the left than the right hemisphere. Furthermore, subgroups of autistic children based on Wing and Gould's system displayed distinct patterns of brain activity. Compared to autistic children classified as “active-but-odd,” “passive” autistic children displayed reduced alpha EEG power in the frontal region.     

Infants' mu suppression during the observation of real and mimicked goal‐directed actions

Since their discovery in the early 1990s, mirror neurons have been proposed to be related to many social‐communicative abilities, such as imitation. However, research into the early manifestations of the putative neural mirroring system and its role in early social development is still inconclusive. In the current EEG study, mu suppression, generally thought to reflect activity in neural mirroring systems was investigated in 18‐ to 30‐month‐olds during the observation of object manipulations as well as mimicked actions. EEG power data recorded from frontal, central, and parietal electrodes were analysed. As predicted, based on previous research, mu wave suppression was found over central electrodes during action observation and execution. In addition, a similar suppression was found during the observation of intransitive, mimicked hand movements. To a lesser extent, the results also showed mu suppression at parietal electrode sites, over all three conditions. Mu wave suppression during the observation of hand movements and during the execution of actions was significantly correlated with quality of imitation, but not with age or language level.