Mapping lexical-semantic networks and determining hemispheric language dominance: Do task design, sex, age, and language performance make a difference?
Abstract Blocked and event-related fMRI designs are both commonly used to localize language networks and determine hemispheric dominance in research and clinical settings. We compared activation profiles on a semantic monitoring task using one of the two designs in a total of 43 healthy individual to determine whether task design or subject-specific factors (i.e., age, sex, or language performance) influence activation patterns. We found high concordance between the two designs within core language regions, including the inferior frontal, posterior temporal, and basal temporal region. However, differences emerged within inferior parietal cortex. Subject-specific factors did not influence activation patterns, nor did they interact with task design. These results suggest that despite high concordance within perisylvian regions that are robust to subject-specific factors, methodological differences between blocked and event-related designs may contribute to parietal activations. These findings provide important information for researchers incorporating fMRI results into meta-analytic studies, as well as for clinicians using fMRI to guide pre-surgical planning.
: Numerous cognitive domains have been associated with the lateral parietal cortex, yet how these disparate functions are packed into this region remains unclear. Whilst areas within the dorsal and the ventral parietal cortex (DPC and VPC) show differential function, there is considerable disagreement as to what these functions might be. Studies focussed on individual domains have plotted out variations of function across the region. Direct cross-domain comparisons are rare yet, when they have b...
#1Yu-Hsuan A. Chang(UCSD: University of California, San Diego)H-Index: 7
#2Nobuko Kemmotsu(UCSD: University of California, San Diego)H-Index: 9
Last. Carrie R. McDonald(UCSD: University of California, San Diego)H-Index: 38
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Abstract This study explored the relationships among multimodal imaging, clinical features, and language impairment in patients with left temporal lobe epilepsy (LTLE). Fourteen patients with LTLE and 26 controls underwent structural MRI, functional MRI, diffusion tensor imaging, and neuropsychological language tasks. Laterality indices were calculated for each imaging modality and a principal component (PC) was derived from language measures. Correlations were performed among imaging measures, ...
Reading requires accurate and rapid distinction between similar visual stimuli. Thesen and colleagues use human intracranial electrophysiology and brain imaging to show that letter-selective responses, in an area of the brain immediately posterior to the visual word-form area, occur before word selection.
Last. Laurent Cohen(UPMC: Pierre-and-Marie-Curie University)H-Index: 48
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Reading systematically activates the left lateral occipitotemporal sulcus, at a site known as the visual word form area (VWFA). This site is reproducible across individuals/scripts, attuned to reading-specific processes, and partially selective for written strings relative to other categories such as line drawings. Lesions affecting the VWFA cause pure alexia, a selective deficit in word recognition. These findings must be reconciled with the fact that human genome evolution cannot have been inf...
#1Carrie R. McDonald(UCSD: University of California, San Diego)H-Index: 38
#2Thomas Thesen(UCSD: University of California, San Diego)H-Index: 33
Last. Eric Halgren(UCSD: University of California, San Diego)H-Index: 87
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article Repetition priming is a core feature of memory processing whose anatomical correlates remain poorly understood. In this study, we use advanced multimodal imaging (functional magnetic resonance imaging (fMRI) and magnetoencephalography; MEG) to investigate the spatiotemporal profile of repetition priming. We use intracranial electroencephalography (iEEG) to validate our fMRI/MEG measurements. Twelve controls completed a semantic judgment task with fMRI and MEG that included words presente...
#2Bruce Fischl(MIT: Massachusetts Institute of Technology)H-Index: 115
Last. Eric Halgren(UCSD: University of California, San Diego)H-Index: 87
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Abstract Precise localization of sulco-gyral structures of the human cerebral cortex is important for the interpretation of morpho-functional data, but requires anatomical expertise and is time consuming because of the brain's geometric complexity. Software developed to automatically identify sulco-gyral structures has improved substantially as a result of techniques providing topologically correct reconstructions permitting inflated views of the human brain. Here we describe a complete parcella...
#1Dominic Holland(UCSD: University of California, San Diego)H-Index: 49
#2Joshua M. Kuperman(UCSD: University of California, San Diego)H-Index: 26
Last. Anders M. Dale(UCSD: University of California, San Diego)H-Index: 166
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Abstract Single-shot Echo Planar Imaging (EPI) is one of the most efficient magnetic resonance imaging (MRI) acquisition schemes, producing relatively high-definition images in 100 ms or less. These qualities make it desirable for Diffusion Tensor Imaging (DTI), functional MRI (fMRI), and Dynamic Susceptibility Contrast MRI (DSC-MRI). However, EPI suffers from severe spatial and intensity distortion due to B 0 field inhomogeneity induced by magnetic susceptibility variations. Anatomically accura...
#2Rutvik H. Desai(MCW: Medical College of Wisconsin)H-Index: 26
Last. Lisa L. Conant(MCW: Medical College of Wisconsin)H-Index: 20
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Semantic memory refers to knowledge about people, objects, actions, relations, self, and culture acquired through experience. The neural systems that store and retrieve this information have been studied for many years, but a consensus regarding their identity has not been reached. Using strict inclusion criteria, we analyzed 120 functional neuroimaging studies focusing on semantic processing. Reliable areas of activation in these studies were identified using the activation likelihood estimate ...
#1Carrie R. McDonald(UCSD: University of California, San Diego)H-Index: 38
#2Thomas Thesen(UCSD: University of California, San Diego)H-Index: 33
Last. Eric Halgren(UCSD: University of California, San Diego)H-Index: 87
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Summary Purpose: To examine distributed patterns of language processing in healthy controls and patients with epilepsy using magnetoencephalography (MEG), and to evaluate the concordance between laterality of distributed MEG sources and language laterality as determined by the intracarotid amobarbital procedure (IAP). Methods: MEG was performed in 10 healthy controls using an anatomically constrained, noise-normalized distributed source solution (dynamic statistical parametric map, dSPM). Distri...
The quantitative analysis of pooled data from related fMRI experiments has the potential to significantly accelerate progress in brain mapping. Such data-pooling can be achieved through meta-analysis (the pooled analysis of published results), mega-analysis (the pooled analysis of raw data) or multi-site studies which can be seen as designed mega-analyses. Current limitations in function-location brain mapping and how data-pooling can be used to remediate them are reviewed, with particular atten...
Categorical and associative relationships among words are two key forms of semantic knowledge. In this study, we examined ageing and gender effects on the processing of both types of semantic relat...
Last. Li Hai Tan(SZU: Shenzhen University)H-Index: 50
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: Men and women process language differently, but how the brain functions to support this difference is poorly understood. A few studies reported sex influences on brain activation for language, whereas others failed to detect the difference at the functional level. Recent advances of brain network analysis have shown great promise in picking up brain connectivity differences between sexes, leading us to hypothesize that the functional connections among distinct brain regions for language may di...
#1Erik Kaestner(UCSD: University of California, San Diego)H-Index: 10
#2Anny Reyes(UCSD: University of California, San Diego)H-Index: 10
Last. Carrie R. McDonald(UCSD: University of California, San Diego)H-Index: 38
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OBJECTIVE: To identify neuroimaging and clinical biomarkers associated with a language-impaired phenotype in refractory temporal lobe epilepsy (TLE). METHODS: Eighty-five patients with TLE were characterized as language-impaired (TLE-LI) or non-language-impaired (TLE-NLI) based on comprehensive neuropsychological testing. Structural magnetic resonance imaging (MRI), diffusion tensor imaging, and functional MRI (fMRI) were obtained in patients and 47 healthy controls (HC). fMRI activations and co...