Interhemispheric compensation: A hypothesis of TMS-induced effects on language-related areas

2008 ◽  
Vol 23 (4) ◽  
pp. 281-288 ◽  
Author(s):  
Jamila Andoh ◽  
Jean-Luc Martinot
Keyword(s):  
Language Processing ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Brain Regions ◽  
Auditory Hallucinations ◽  
Language Recovery ◽  
Functional Organisation ◽  
Virtual Lesion ◽  
Left And Right ◽  
Local Interference ◽  
The Brain

AbstractRepetitive transcranial magnetic stimulation (rTMS) applied over brain regions responsible for language processing is used to curtail potentially auditory hallucinations in schizophrenia patients and to investigate the functional organisation of language-related areas. Variability of effects is, however, marked across studies and between subjects. Furthermore, the mechanisms of action of rTMS are poorly understood.Here, we reviewed different factors related to the structural and functional organisation of the brain that might influence rTMS-induced effects. Then, by analogy with aphasia studies, and the plastic-adaptive changes in both the left and right hemispheres following aphasia recovery, a hypothesis is proposed about rTMS mechanisms over language-related areas (e.g. Wernicke, Broca). We proposed that the local interference induced by rTMS in language-related areas might be analogous to aphasic stroke and might lead to a functional reorganisation in areas connected to the virtual lesion for language recovery.

Neuro-Clinical Signatures of Language Impairments: A Theoretical Framework for Function-to-structure Mapping in Clinics

2020 ◽  
Vol 20 (9) ◽  
pp. 800-811 ◽  
Author(s):  
Ferath Kherif ◽  
Sandrine Muller
Keyword(s):  
Brain Mapping ◽  
Theoretical Framework ◽  
Brain Regions ◽  
Language Impairments ◽  
Structure Mapping ◽  
Language Functions ◽  
The Past ◽  
Language Recovery ◽  
The Brain ◽  
Bow Tie

In the past decades, neuroscientists and clinicians have collected a considerable amount of data and drastically increased our knowledge about the mapping of language in the brain. The emerging picture from the accumulated knowledge is that there are complex and combinatorial relationships between language functions and anatomical brain regions. Understanding the underlying principles of this complex mapping is of paramount importance for the identification of the brain signature of language and Neuro-Clinical signatures that explain language impairments and predict language recovery after stroke. We review recent attempts to addresses this question of language-brain mapping. We introduce the different concepts of mapping (from diffeomorphic one-to-one mapping to many-to-many mapping). We build those different forms of mapping to derive a theoretical framework where the current principles of brain architectures including redundancy, degeneracy, pluri-potentiality and bow-tie network are described.

Oral reading in bilingual aphasia: Evidence from Mongolian and Chinese

2007 ◽  
Vol 10 (2) ◽  
pp. 201-210 ◽  
Author(s):  
BRENDAN STUART WEEKES ◽  
I FAN SU ◽  
WENGANG YIN ◽  
XIHONG ZHANG
Keyword(s):  
Language Processing ◽  
Oral Reading ◽  
Word Processing ◽  
Brain Regions ◽  
Writing Systems ◽  
Word Comprehension ◽  
Bilingual Aphasia ◽  
Written Word ◽  
Cognitive Neuropsychological ◽  
The Brain

Cognitive neuropsychological studies of bilingual patients with aphasia have contributed to our understanding of how the brain processes different languages. The question we asked is whether differences in script have any impact on language processing in bilingual aphasic patients who speak languages with different writing systems: Chinese and Mongolian. We observed a pattern of greater impairment to written word comprehension and oral reading in L2 (Chinese) than in L1 (Mongolian) for two patients. We argue that differences in script have only a minimal effect on written word processing in bilingual aphasia when the age of acquisition, word frequency and imageability of lexical items is controlled. Our conclusion is that reading of familiar words in Mongolian and Chinese might not require independent cognitive systems or brain regions.

The Brain Basis of Language Processing: From Structure to Function

2011 ◽  
Vol 91 (4) ◽  
pp. 1357-1392 ◽  
Author(s):  
Angela D. Friederici
Keyword(s):  
Language Processing ◽  
Right Hemisphere ◽  
Structural Connectivity ◽  
Temporal Cortex ◽  
Brain Regions ◽  
Posterior Portion ◽  
Language Functions ◽  
Marker Studies ◽  
The Right ◽  
The Brain

Language processing is a trait of human species. The knowledge about its neurobiological basis has been increased considerably over the past decades. Different brain regions in the left and right hemisphere have been identified to support particular language functions. Networks involving the temporal cortex and the inferior frontal cortex with a clear left lateralization were shown to support syntactic processes, whereas less lateralized temporo-frontal networks subserve semantic processes. These networks have been substantiated both by functional as well as by structural connectivity data. Electrophysiological measures indicate that within these networks syntactic processes of local structure building precede the assignment of grammatical and semantic relations in a sentence. Suprasegmental prosodic information overtly available in the acoustic language input is processed predominantly in a temporo-frontal network in the right hemisphere associated with a clear electrophysiological marker. Studies with patients suffering from lesions in the corpus callosum reveal that the posterior portion of this structure plays a crucial role in the interaction of syntactic and prosodic information during language processing.

scholarly journals Using Diffusion Tensor Imaging to examine brain structural plasticity and language experience

2019 ◽  
Author(s):  
Gigi Luk ◽  
Christos Pliatsikas
Keyword(s):  
Language Processing ◽  
Brain Structure ◽  
Language Use ◽  
Diffusion Tensor ◽  
Brain Plasticity ◽  
Structural Connectivity ◽  
Brain Regions ◽  
Language Experience ◽  
Brain Correlates ◽  
The Brain

Recent advances in neuroimaging methods have led to a renewed interest in the brain correlates of language processing. Most intriguing is how experiences of language use relates to variation in brain structure and how brain structure predicts language acquisition. These two lines of inquiry have important implications on considering language use as an experience-dependent mechanism that induces brain plasticity. This paper focuses on the structural connectivity of the brain, as delivered by white matter, i.e. the collections of the axons of the brain neurons that provide connectivity between brain regions. Tract-Based Spatial Statistics (TBSS), a method commonly used in the field, will be presented in detail. Readers will be introduced to procedures for the extraction of indices of variation in WM structure such as fractional anisotropy. Furthermore, the role of individual differences in WM and changes in WM pertaining to bilingual experience and language processing will be used as examples to illustrate the applicability of this method.

scholarly journals Frequency-specific directed interactions in the human brain network for language

2017 ◽  
Author(s):  
J. M. Schoffelen ◽  
A. Hultén ◽  
N. Lam ◽  
A. Marquand ◽  
J. Uddén ◽  
...  
Keyword(s):  
Language Processing ◽  
Brain Regions ◽  
Brain Network ◽  
Causality Analysis ◽  
Functional Topology ◽  
Using Data ◽  
Beta Frequency ◽  
Bidirectional Interactions ◽  
The Brain

AbstractThe brain’s remarkable capacity for language requires bidirectional interactions between functionally specialized brain regions. We used magnetoencephalography to investigate interregional interactions in the brain network for language, while 102 participants were reading sentences. Using Granger causality analysis, we identified inferior frontal cortex and anterior temporal regions to receive widespread input, and middle temporal regions to send widespread output. This fits well with the notion that these regions play a central role in language processing. Characterization of the functional topology of this network, using data-driven matrix factorization, which allowed for partitioning into a set of subnetworks, revealed directed connections at distinct frequencies of interaction. Connections originating from temporal regions peaked at alpha frequency, whereas connections originating from frontal and parietal regions peaked at beta frequency. These findings indicate that processing different types of linguistic information may depend on the contributions of distinct brain rhythms.One Sentence SummaryCommunication between language relevant areas in the brain is supported by rhythmic synchronization, where different rhythms reflect the direction of information flow.

scholarly journals Syntactic representations in the human brain: beyond effort-based metrics

2020 ◽  
Author(s):  
Aniketh Janardhan Reddy ◽  
Leila Wehbe
Keyword(s):  
Language Processing ◽  
Syntactic Structure ◽  
Brain Activity ◽  
Brain Regions ◽  
Syntactic Processing ◽  
Language System ◽  
Language Studies ◽  
Syntactic Information ◽  
Show Evidence ◽  
The Brain

AbstractWe are far from having a complete mechanistic understanding of the brain computations involved in language processing and of the role that syntax plays in those computations. Most language studies do not computationally model syntactic structure, and most studies that do model syntactic processing use effort-based metrics. These metrics capture the effort needed to process the syntactic information given by every word [9, 10, 25]. They can reveal where in the brain syntactic processing occurs, but not what features of syntax are processed by different brain regions. Here, we move beyond effort-based metrics and propose explicit features capturing the syntactic structure that is incrementally built while a sentence is being read. Using these features and functional Magnetic Resonance Imaging (fMRI) recordings of participants reading a natural text, we study the brain representation of syntax. We find that our syntactic structure-based features are better than effort-based metrics at predicting brain activity in various parts of the language system. We show evidence of the brain representation of complex syntactic information such as phrase and clause structures. We see that regions well-predicted by syntactic features are distributed in the language system and are not distinguishable from those processing semantics. Our results call for a shift in the approach used for studying syntactic processing.

scholarly journals Early Detection of Alzheimer’s Disease: Detecting Asymmetries with a Return Random Walk Link Predictor

Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 465
Author(s):  
Manuel Curado ◽  
Francisco Escolano ◽  
Miguel A. Lozano ◽  
Edwin R. Hancock
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Random Walk ◽  
Early Stage ◽  
Directed Graphs ◽  
Brain Regions ◽  
Functional Magnetic Resonance ◽  
Left And Right ◽  
The Brain ◽  
Analyze Data

Alzheimer’s disease has been extensively studied using undirected graphs to represent the correlations of BOLD signals in different anatomical regions through functional magnetic resonance imaging (fMRI). However, there has been relatively little analysis of this kind of data using directed graphs, which potentially offer the potential to capture asymmetries in the interactions between different anatomical brain regions. The detection of these asymmetries is relevant to detect the disease in an early stage. For this reason, in this paper, we analyze data extracted from fMRI images using the net4Lap algorithm to infer a directed graph from the available BOLD signals, and then seek to determine asymmetries between the left and right hemispheres of the brain using a directed version of the Return Random Walk (RRW). Experimental evaluation of this method reveals that it leads to the identification of anatomical brain regions known to be implicated in the early development of Alzheimer’s disease in clinical studies.

scholarly journals The topology of higher-order complexes associated with brain hubs in human connectomes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Miroslav Andjelković ◽  
Bosiljka Tadić ◽  
Roderick Melnik
Keyword(s):  
Complex Dynamics ◽  
Simplicial Complexes ◽  
Brain Regions ◽  
Higher Order ◽  
Core Networks ◽  
Right Cerebral Hemisphere ◽  
Left And Right ◽  
Order Complexes ◽  
The Brain

Abstract Higher-order connectivity in complex systems described by simplexes of different orders provides a geometry for simplex-based dynamical variables and interactions. Simplicial complexes that constitute a functional geometry of the human connectome can be crucial for the brain complex dynamics. In this context, the best-connected brain areas, designated as hub nodes, play a central role in supporting integrated brain function. Here, we study the structure of simplicial complexes attached to eight global hubs in the female and male connectomes and identify the core networks among the affected brain regions. These eight hubs (Putamen, Caudate, Hippocampus and Thalamus-Proper in the left and right cerebral hemisphere) are the highest-ranking according to their topological dimension, defined as the number of simplexes of all orders in which the node participates. Furthermore, we analyse the weight-dependent heterogeneity of simplexes. We demonstrate changes in the structure of identified core networks and topological entropy when the threshold weight is gradually increased. These results highlight the role of higher-order interactions in human brain networks and provide additional evidence for (dis)similarity between the female and male connectomes.

scholarly journals Functional Neuroanatomy of Meaning Acquisition from Context

2008 ◽  
Vol 20 (12) ◽  
pp. 2153-2166 ◽  
Author(s):  
Anna Mestres-Missé ◽  
Estela Càmara ◽  
Antoni Rodriguez-Fornells ◽  
Michael Rotte ◽  
Thomas F. Münte
Keyword(s):  
Language Processing ◽  
Inferior Frontal Gyrus ◽  
Imaging Study ◽  
Brain Regions ◽  
Brain Network ◽  
Parahippocampal Gyrus ◽  
Middle Temporal Gyrus ◽  
Functional Neuroanatomy ◽  
Subcortical Structures ◽  
The Brain

An important issue in language learning is how new words are integrated in the brain representations that sustain language processing. To identify the brain regions involved in meaning acquisition and word learning, we conducted a functional magnetic resonance imaging study. Young participants were required to deduce the meaning of a novel word presented within increasingly constrained sentence contexts that were read silently during the scanning session. Inconsistent contexts were also presented in which no meaning could be assigned to the novel word. Participants showed meaning acquisition in the consistent but not in the inconsistent condition. A distributed brain network was identified comprising the left anterior inferior frontal gyrus (BA 45), the middle temporal gyrus (BA 21), the parahippocampal gyrus, and several subcortical structures (the thalamus and the striatum). Drawing on previous neuroimaging evidence, we tentatively identify the roles of these brain areas in the retrieval, selection, and encoding of the meaning.

Repetitive TMS as a Probe of Mood In Health and Disease

CNS Spectrums ◽  
1997 ◽  
Vol 2 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Mark S. George ◽  
Andrew M. Speer ◽  
Eric M. Wassermann ◽  
Timothy A. Kimbrell ◽  
Wendol A. William ◽  
...  
Keyword(s):  
Functional Neuroimaging ◽  
Single Photon ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Photon Emission ◽  
Brain Regions ◽  
Emission Tomography ◽  
Single Photon Emission ◽  
Positron Emission ◽  
Health And Disease ◽  
The Brain

AbstractRecent advances in functional neuroimaging (including positron emission tomography, single-photon emission tomography, and fast magnetic resonance imaging) have allowed better understanding of the brain regions involved in regulating normal and pathological moods. Repetitive transcranial magnetic stimulation (rTMS) has the ability to stimulate or temporarily impair brain regions, which makes it a powerful tool for directly testing theories of the neurologic basis of mood regulation.

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