Speech–Brain Frequency Entrainment of Dyslexia with and without Phonological Deficits

Developmental dyslexia is a cognitive disorder characterized by difficulties in linguistic processing. Our purpose is to distinguish subtypes of developmental dyslexia by the level of speech–EEG frequency entrainment (δ: 1–4; β: 12.5–22.5; γ1: 25–35; and γ2: 35–80 Hz) in word/pseudoword auditory discrimination. Depending on the type of disabilities, dyslexics can divide into two subtypes—with less pronounced phonological deficits (NoPhoDys—visual dyslexia) and with more pronounced ones (PhoDys—phonological dyslexia). For correctly recognized stimuli, the δ-entrainment is significantly worse in dyslexic children compared to controls at a level of speech prosody and syllabic analysis. Controls and NoPhoDys show a stronger δ-entrainment in the left-hemispheric auditory cortex (AC), anterior temporal lobe (ATL), frontal, and motor cortices than PhoDys. Dyslexic subgroups concerning normolexics have a deficit of δ-entrainment in the left ATL, inferior frontal gyrus (IFG), and the right AC. PhoDys has higher δ-entrainment in the posterior part of adjacent STS regions than NoPhoDys. Insufficient low-frequency β changes over the IFG, the inferior parietal lobe of PhoDys compared to NoPhoDys correspond to their worse phonological short-term memory. Left-dominant 30 Hz-entrainment for normolexics to phonemic frequencies characterizes the right AC, adjacent regions to superior temporal sulcus of dyslexics. The pronounced 40 Hz-entrainment in PhoDys than the other groups suggest a hearing “reassembly” and a poor phonological working memory. Shifting up to higher-frequency γ-entrainment in the AC of NoPhoDys can lead to verbal memory deficits. Different patterns of cortical reorganization based on the left or right hemisphere lead to differential dyslexic profiles.

Download Full-text

Is Lateropulsion Really Related with a Specific Lesion of the Brain?

Brain Sciences ◽

10.3390/brainsci11030354 ◽

2021 ◽

Vol 11 (3) ◽

pp. 354

Author(s):

Kyoung Lee ◽

Sang Yoo ◽

Eun Ji ◽

Woo Hwang ◽

Yeun Yoo ◽

...

Keyword(s):

Right Hemisphere ◽

Parietal Lobe ◽

Inferior Frontal Gyrus ◽

Brain Lesions ◽

Vertical Posture ◽

Lesion Volume ◽

Precentral Gyrus ◽

Stroke Patients ◽

The Right ◽

Right Hemisphere Stroke

Lateropulsion (pusher syndrome) is an important barrier to standing and gait after stroke. Although several studies have attempted to elucidate the relationship between brain lesions and lateropulsion, the effects of specific brain lesions on the development of lateropulsion remain unclear. Thus, the present study investigated the effects of stroke lesion location and size on lateropulsion in right hemisphere stroke patients. The present retrospective cross-sectional observational study assessed 50 right hemisphere stroke patients. Lateropulsion was diagnosed and evaluated using the Scale for Contraversive Pushing (SCP). Voxel-based lesion symptom mapping (VLSM) analysis with 3T-MRI was used to identify the culprit lesion for SCP. We also performed VLSM controlling for lesion volume as a nuisance covariate, in a multivariate model that also controlled for other factors contributing to pusher behavior. VLSM, combined with statistical non-parametric mapping (SnPM), identified the specific region with SCP. Lesion size was associated with lateropulsion. The precentral gyrus, postcentral gyrus, inferior frontal gyrus, insula and subgyral parietal lobe of the right hemisphere seemed to be associated with the lateropulsion; however, after adjusting for lesion volume as a nuisance covariate, no lesion areas were associated with the SCP scores. The size of the right hemisphere lesion was the only factor most strongly associated with lateropulsion in patients with stroke. These results may be useful for planning rehabilitation strategies of restoring vertical posture and understanding the pathophysiology of lateropulsion in stroke patients.

Download Full-text

Electrostimulation Mapping of Spatial Neglect

Neurosurgery ◽

10.1227/neu.0b013e31822aefd2 ◽

2011 ◽

Vol 69 (6) ◽

pp. 1218-1231 ◽

Cited By ~ 35

Author(s):

Franck-Emmanuel Roux ◽

Olivier Dufor ◽

Valérie Lauwers-Cances ◽

Leila Boukhatem ◽

David Brauge ◽

...

Keyword(s):

Right Hemisphere ◽

Parietal Lobe ◽

Group Analysis ◽

Posterior Part ◽

Line Bisection ◽

Spatial Neglect ◽

Control Group ◽

Cortical Areas ◽

Specificity And Sensitivity ◽

The Right

Abstract BACKGROUND Cortical and subcortical electrostimulation mapping during awake brain surgery for tumor removal is usually used to minimize deficits. OBJECTIVE To use electrostimulation to study neuronal substrates involved in spatial awareness in humans. METHODS Spatial neglect was studied using a line bisection task in combination with electrostimulation mapping of the right hemisphere in 50 cases. Stimulation sites were identified with Talairach coordinates. The behavioral effects induced by stimulation, especially eye movements and deviations from the median, were quantified and compared with preoperative data and a control group. RESULTS Composite and highly individualized spatial neglect maps were generated. Both rightward and leftward deviations were induced, sometimes in the same patient but for different stimulation sites. Group analysis showed that specific and reproducible line deviations were induced by stimulation of discrete cortical areas located in the posterior part of the right superior and middle temporal gyri, inferior parietal lobe, and inferior postcentral and inferior frontal gyri (P > .05). Fiber tracking identified stimulated subcortical areas important to spare as sections of fronto-occipital and superior longitudinal II fascicles. According to preoperative and postoperative neglect battery tests, the specificity and sensitivity of intraoperative line bisection tests were 94% and 83%, respectively. CONCLUSION In humans, discrete cortical areas that are variable in location between individuals but mainly located within the right posterior Sylvian fissure sustain visuospatial attention specifically toward the contralateral or ipsilateral space direction. Line bisection mapping was found to be a reliable method for minimizing spatial neglect caused by brain tumor surgery.

Download Full-text

Covert Speech Arrest Induced by rTMS over Both Motor and Nonmotor Left Hemisphere Frontal Sites

Journal of Cognitive Neuroscience ◽

10.1162/0898929054021157 ◽

2005 ◽

Vol 17 (6) ◽

pp. 928-938 ◽

Cited By ~ 47

Author(s):

Lisa Aziz-Zadeh ◽

Luigi Cattaneo ◽

Magali Rochat ◽

Giacomo Rizzolatti

Keyword(s):

Left Hemisphere ◽

Right Hemisphere ◽

Repetitive Transcranial Magnetic Stimulation ◽

Inferior Frontal Gyrus ◽

Posterior Part ◽

Left Frontal Lobe ◽

Posterior Site ◽

Left Posterior ◽

The Right ◽

Overt Speech

Blocking the capacity to speak aloud (overt speech arrest, SA) may be induced by repetitive transcranial magnetic stimulation (rTMS). The possibility, however, of blocking internal speech (covert SA) has not been explored. To investigate this issue, we conducted two rTMS experiments. In the first experiment, we stimulated two left frontal lobe sites. The first was a motor site (left posterior site) and the second was a nonmotor site located in correspondence to the posterior part of the inferior frontal gyrus (IFG) (left anterior site). The corresponding right hemisphere nonmotor SA site was stimulated as a control. In the second experiment, we focused on the right hemisphere and stimulated a right hemisphere motor site (right posterior site), and, as control sites, a right hemisphere nonmotor site corresponding to the IFG (right anterior site) and a left hemisphere anteromedial site (left control). For both experiments, participants performed a syllable counting task both covertly and overtly for each stimulation site. Longer latencies in this task imply the occurrence of an overt and/or covert SA. All participants showed significantly longer latencies when stimulation was either over the left posterior or the left anterior site, as compared with the right hemisphere site (Experiment 1). This result was observed for the overt and covert speech task alike. During stimulation of the posterior right hemisphere site, a dissociation for overt and covert speech was observed. An overt SA was observed but there was no evidence for a covert SA (Experiment 2). Taken together, the results show that rTMS can induce a covert SA when applied to areas over the brain that are pertinent to language. Furthermore, both the left posterior/motor site and the left anterior/IFG site appear to be essential to language elaboration even when motor output is not required.

Download Full-text

Distinct Neural Correlates of Linguistic and Non-Linguistic Demand

Neurobiology of Language ◽

10.1162/nol_a_00031 ◽

2021 ◽

pp. 1-24

Author(s):

Ian A. Quillen ◽

Melodie Yen ◽

Stephen M. Wilson

Keyword(s):

Task Difficulty ◽

Right Hemisphere ◽

Semantic Network ◽

Inferior Frontal Gyrus ◽

Neural Correlates ◽

Normal Individuals ◽

Linguistic Demand ◽

Neurologically Normal ◽

The Right ◽

Temporal Language

In this study, we investigated how the brain responds to task difficulty in linguistic and non-linguistic contexts. This is important for the interpretation of functional imaging studies of neuroplasticity in post-stroke aphasia, because of the inherent difficulty of matching or controlling task difficulty in studies with neurological populations. Twenty neurologically normal individuals were scanned with fMRI as they performed a linguistic task and a non-linguistic task, each of which had two levels of difficulty. Critically, the tasks were matched across domains (linguistic, non-linguistic) for accuracy and reaction time, such that the differences between the easy and difficult conditions were equivalent across domains. We found that non-linguistic demand modulated the same set of multiple demand (MD) regions that have been identified in many prior studies. In contrast, linguistic demand modulated MD regions to a much lesser extent, especially nodes belonging to the dorsal attention network. Linguistic demand modulated a subset of language regions, with the left inferior frontal gyrus most strongly modulated. The right hemisphere region homotopic to Broca’s area was also modulated by linguistic but not non-linguistic demand. When linguistic demand was mapped relative to non-linguistic demand, we also observed domain by difficulty interactions in temporal language regions as well as a widespread bilateral semantic network. In sum, linguistic and non-linguistic demand have strikingly different neural correlates. These findings can be used to better interpret studies of patients recovering from aphasia. Some reported activations in these studies may reflect task performance differences, while others can be more confidently attributed to neuroplasticity.

Download Full-text

Magnetoencephalography Resting-State Correlates of Executive and Language Components of Verbal Fluency

10.21203/rs.3.rs-821087/v1 ◽

2021 ◽

Author(s):

Victor Oswald ◽

Younes Zerouali ◽

Aubrée Boulet-Craig ◽

Maja Krajinovic ◽

Caroline Laverdière ◽

...

Keyword(s):

Resting State ◽

Verbal Fluency ◽

Right Hemisphere ◽

Spectral Power ◽

Inferior Frontal Gyrus ◽

Factor Loading ◽

Language Abilities ◽

Verbal Test ◽

Eyes Open ◽

The Right

Abstract Verbal fluency (VF) is a heterogeneous test that requires executive functions as well as language abilities. The purpose of this study was to elucidate the specificity of the resting state MEG correlates of the executive and language components. To this end, we administered a VFtest, another verbal test (Vocabulary), and another executive test (Trail Making Test), and we recorded 5-min eyes-open resting-state MEG data in 28 healthy participants. We used source-reconstructed spectral power estimates to compute correlation/anticorrelation MEG clusters with the performance at each test, as well as with the advantage in performance between tests, across individuals using cluster-level statisticsin the standard frequency bands. By obtaining conjunction clusters between verbal fluency scores and factor loading obtained for verbal fluency and each of the two other tests, we showed a core of slow clusters (delta to beta) localized in the right hemisphere, in adjacent parts of the premotor, pre-central and post-central cortex in the mid-lateral regions related to executive monitoring. We also found slow parietal clusters bilaterally and a cluster in the gamma 2 and 3 bandsin the left inferior frontal gyrus likely associated with phonological processinginvolved in verbal fluency.

Download Full-text

Decreases in Frontal and Parietal Lobe Regional Cerebral Blood Flow Related to Habituation

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.1992.78 ◽

1992 ◽

Vol 12 (4) ◽

pp. 546-553 ◽

Cited By ~ 39

Author(s):

Steven Warach ◽

Ruben C. Gur ◽

Raquel E. Gur ◽

Brett E. Skolnick ◽

Walter D. Obrist ◽

...

Keyword(s):

Right Hemisphere ◽

Parietal Lobe ◽

Brain Activity ◽

Inhalation Technique ◽

Attentional Processes ◽

Left Handed ◽

Verbal Tasks ◽

Spatial Tasks ◽

Regional Specificity ◽

The Right

We previously reported decreased mean CBF between consecutive resting conditions, ascribed to habituation. Here we address the regional specificity of habituation over three consecutive flow studies. Regional CBF (rCBF) was measured in 55 adults (12 right-handed men, 12 right-handed women, 14 left-handed men, 17 left-handed women), with the 133Xe inhalation technique, during three conditions: Resting, verbal tasks (analogies), and spatial tasks (line orientation). Changes in rCBF attributable to the cognitive tasks were eliminated by correcting these values to a resting equivalent. There was a progressive decrease in mean rCBF over time, reflecting habituation. This effect differed by region, with specificity at frontal (prefrontal, inferior frontal, midfrontal, superior frontal) and inferior parietal regions. In the inferior parietal region, habituation was more marked in the left than the right hemisphere. Right-handers showed greater habituation than did left-handers. There was no sex difference in global habituation, but males showed greater left whereas females showed greater right hemispheric habituation. The results suggest that habituation to the experimental setting has measurable effects on rCBF, which are differently lateralized for men and women. These effects are superimposed on task activation and are most pronounced in regions that have been implicated in attentional processes. Thus, regional decrement in brain activity related to habituation seems to complement attentional effects, suggesting a neural network for habituation reciprocating that for attention.

Download Full-text

Neural Basis of Depression Related to a Dominant Right Hemisphere: A Resting-State fMRI Study

Behavioural Neurology ◽

10.1155/2018/5024520 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10 ◽

Cited By ~ 8

Author(s):

Mi Li ◽

Hongpei Xu ◽

Shengfu Lu

Keyword(s):

Right Hemisphere ◽

Inferior Frontal Gyrus ◽

Middle Temporal Gyrus ◽

Neural Basis ◽

Middle Temporal ◽

Middle Occipital Gyrus ◽

The Right ◽

Depressive Patients ◽

The Brain ◽

Left Middle

Background. In the past, studies on the lateralization of the left and right hemispheres of the brain suggested that depression is dominated by the right hemisphere of the brain, but the neural basis of this theory remains unclear. Method. Functional magnetic resonance imaging of the brain was performed in 22 depressive patients and 15 healthy controls. The differences in the mean values of the regional homogeneity (ReHo) of two groups were compared, and the low-frequency amplitudes of these differential brain regions were compared. Results. The results show that compared with healthy subjects, depressive patients had increased ReHo values in the right superior temporal gyrus, right middle temporal gyrus, left inferior temporal gyrus, left middle temporal gyrus, right middle frontal gyrus, triangular part of the right inferior frontal gyrus, orbital part of the right inferior frontal gyrus, right superior occipital gyrus, right middle occipital gyrus, bilateral anterior cingulate, and paracingulate gyri; reduced ReHo values were seen in the right fusiform gyrus, left middle occipital gyrus, left lingual gyrus, and left inferior parietal except in the supramarginal and angular gyri. Conclusions. The results show that regional homogeneity mainly occurs in the right brain, and the overall performance of the brain is such that right hemisphere synchronization is enhanced while left hemisphere synchronization is weakened. ReHo abnormalities in the resting state can predict abnormalities in individual neurological activities that reflect changes in the structure and function of the brain; abnormalities shown with this indicator are the neuronal basis for the phenomenon that the right hemisphere of the brain has a dominant effect on depression.

Download Full-text

Stop and Go: The Neural Basis of Selective Movement Prevention

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2009.21081 ◽

2009 ◽

Vol 21 (6) ◽

pp. 1193-1203 ◽

Cited By ~ 69

Author(s):

James P. Coxon ◽

Cathy M. Stinear ◽

Winston D. Byblow

Keyword(s):

Motor Cortex ◽

Right Hemisphere ◽

Inferior Frontal Gyrus ◽

Middle Finger ◽

Neural Basis ◽

Movement Initiation ◽

Stop And Go ◽

Inferior Parietal Cortex ◽

Supplementary Motor Cortex ◽

The Right

Converging lines of evidence show that volitional movement prevention depends on the right prefrontal cortex (PFC), especially the right inferior frontal gyrus (IFG). Selective movement prevention refers to the rapid prevention of some, but not all, movement. It is unknown whether the IFG, or other prefrontal areas, are engaged when movement must be selectively prevented, and whether additional cortical areas are recruited. We used rapid event-related fMRI to investigate selective and nonselective movement prevention during performance of a temporally demanding anticipatory task. Most trials involved simultaneous index and middle finger extension. Randomly interspersed trials required the prevention of one, or both, finger movements. Regions of the right hemisphere, including the IFG, were active for selective and nonselective movement prevention, with an overlap in the inferior parietal cortex and the middle frontal gyrus. Selective movement prevention caused a significant delay in movement initiation of the other digit. These trials were associated with activation of the medial frontal cortex. The results provide support for a right-hemisphere network that temporarily “brakes” all movement preparation. When movement is selectively prevented, the supplementary motor cortex (SMA/pre-SMA) may participate in conflict resolution and subsequent reshaping of excitatory drive to the motor cortex.

Download Full-text

Mathematics and TMS

10.1093/oxfordhb/9780198568926.013.0033 ◽

2012 ◽

Author(s):

Elena Rusconi ◽

Carlo Umiltà

Keyword(s):

Transcranial Magnetic Stimulation ◽

Magnetic Stimulation ◽

Right Hemisphere ◽

Parietal Lobe ◽

Brain Activation ◽

Number Line ◽

Mathematical Cognition ◽

Mental Number Line ◽

The Right ◽

The Relationship

This article introduces the relationship between mathematical cognition and transcranial magnetic stimulation (TMS). The mental number line is located in the parietal lobe. Studies employing TMS have explored issues related to the mental number line. This article reviews the studies centered on the magnitude code. The results show that even though the parietal activation is nearly always present in both hemispheres, it is often asymmetric, being greater in the right hemisphere when quantification of nonverbal and nonsymbolic material is required. Neuropsychological studies confirm the relation between the magnitude code and the parietal lobe. The extent to which number-related processes are number specific, and the extent to which they overlap with other aspects of spatial or magnitude representation, is currently a burgeoning area of research. Current work is aimed to disrupt numerical processes and observe concomitant changes in brain activation.

Download Full-text

Sex Differences in Anatomical Rich-Club and Structural–Functional Coupling in the Human Brain Network

Cerebral Cortex ◽

10.1093/cercor/bhaa335 ◽

2020 ◽

Cited By ~ 1

Author(s):

Shuo Zhao ◽

Gongshu Wang ◽

Ting Yan ◽

Jie Xiang ◽

Xuexue Yu ◽

...

Keyword(s):

Sex Differences ◽

Cognitive Function ◽

Parietal Lobe ◽

Diffusion Tensor ◽

Inferior Frontal Gyrus ◽

Structural Connectivity ◽

Parahippocampal Gyrus ◽

Functional Coupling ◽

Rich Club ◽

The Right

Abstract Structural and functional differences between the brains of female and male adults have been well documented. However, potential sex differences in the patterns of rich-club organization and the coupling between their structural connectivity (SC) and functional connectivity (FC) remain to be determined. In this study, functional magnetic resonance imaging and diffusion tensor imaging techniques were combined to examine sex differences in rich-club organization. Females had a stronger SC-FC coupling than males. Moreover, stronger SC-FC coupling in the females was primarily located in feeder connections and non–rich-club nodes of the left inferior frontal gyrus and inferior parietal lobe and the right superior frontal gyrus and superior parietal gyrus, whereas higher coupling strength in males was primarily located in rich-club connections and rich-club node of the right insula, and non-rich-club nodes of the left hippocampus and the right parahippocampal gyrus. Sex-specific patterns in correlations were also shown between SC-FC coupling and cognitive function, including working memory and reasoning ability. The topological changes in rich-club organization provide novel insight into sex-specific effects on white matter connections that underlie a potential network mechanism of sex-based differences in cognitive function.

Download Full-text