Hemispheric asymmetries in language-related pathways: A combined functional MRI and tractography study

Powell, Harrison; Parker, Geoffrey; Alexander, Daniel C.; Symms, Mark R.; Boulby, Philip A.; Wheeler-Kingshott, Claudia A. M.; Barker, Gareth J.; Noppeney, Uta; Koepp, Matthias J.; Duncan, John S.

doi:10.1016/j.neuroimage.2006.03.011

Cited by 376 publications

(315 citation statements)

References 58 publications

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“…In general, our findings are consistent with previous neuroimaging studies showing structural (11,12,22,36,37) and maturational (38) differences of the arcuate fasciculus between left and right hemispheres. However, the existence of an arcuate fasciculus in the right human brain has never been confirmed in postmortem studies and, to the best of our knowledge, such a strong relationship between brain pathway architecture and cognitive performance has never previously been described.…”

Section: Resultssupporting

confidence: 93%

“…DT-MRI tractography is a noninvasive technique that, instead of visualizing axons directly, reconstructs their trajectories by measuring the diffusivity of water along different directions and tracing a pathway of least hindrance to diffusion (parallel to the dominant fiber orientation) to form continuous pathways. DT-MRI facilitates the study of large-scale brain networks, including those subserving language (11)(12)(13)(20)(21)(22). Recent DT-MRI investigations have revealed three important parts of the language network (21).…”

mentioning

confidence: 99%

“…Recent DT-MRI investigations have revealed three important parts of the language network (21). First, there is the well established direct pathway (21) connecting Wernicke's territory in the left temporal lobe with Broca's territory in the left frontal lobe through the arcuate fasciculus (11)(12)(13)(20)(21)(22). In addition, there is an indirect pathway (21) consisting of two segments, an anterior segment linking Broca's territory with the inferior parietal lobe (Geschwind's territory) (21), and a posterior segment linking Geschwind's territory with Wernicke's territory (13,20,21).…”

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confidence: 99%

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Symmetries in human brain language pathways correlate with verbal recall

Catani

Allin

Husain

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Lateralization of language to the left hemisphere is considered a key aspect of human brain organization. We used diffusion tensor MRI to perform in vivo virtual dissection of language pathways to assess the relationship between brain asymmetry and cognitive performance in the normal population. Our findings suggest interhemispheric differences in direct connections between Broca's and Wernicke's territories, with extreme leftward lateralization in more than half of the subjects and bilateral symmetrical distribution in only 17.5% of the subjects. Importantly, individuals with more symmetric patterns of connections are better overall at remembering words using semantic association. Moreover, preliminary analysis suggests females are more likely to have a symmetrical pattern of connections. These findings suggest that the degree of lateralization of perisylvian pathways is heterogeneous in the normal population and, paradoxically, bilateral representation, not extreme lateralization, might ultimately be advantageous for specific cognitive functions.arcuate fasciculus ͉ brain asymmetry ͉ diffusion tensor imaging ͉ language lateralization ͉ verbal memory

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Section: Resultssupporting

confidence: 93%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Symmetries in human brain language pathways correlate with verbal recall

Catani

Allin

Husain

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

586

520

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“…In addition, given that the anatomic frontotemporal connections seem to be stronger in LH than in RH (Glasser & Rilling, 2008;Powell et al, 2006), this could imply that some right IFG dominant participants have less developed connections between their RH IFG and RH vOT cortex, even though their speech production is atypical at the functional level. This suggestion of course is a general observation and needs future research by for example Diffusion…”

Section: Discussionmentioning

confidence: 99%

Colateralization of Broca’s area and the visual word form area in left-handers: fMRI evidence

2012

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“…Pyramidal cells at the left PT are larger in size and density (Hutsler and Gazzaniga, 1996), and the left PT can contain more subsystems than the right PT within the same volume, suggesting superior fine-grained intrinsic connectivity (Galuske et al, 2000). Similarly at the macroscopic level, white-matter tracts linking temporal and frontal lobes are more widespread and greater in volume in the left hemisphere (Powell et al, 2006;Rilling et al, 2008). From the functional point of view, several neuroimaging studies have pointed to asymmetries in the temporal cortices, especially in language-related tasks.…”

Section: Discussionmentioning

confidence: 99%

Genome-Wide Linkage Analysis of Human Auditory Cortical Activation Suggests Distinct Loci on Chromosomes 2, 3, and 8

et al. 2012

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Neural processes are explored through macroscopic neuroimaging and microscopic molecular measures, but the two levels remain primarily detached. The identification of direct links between the levels would facilitate use of imaging signals as probes of genetic function and, vice versa, access to molecular correlates of imaging measures. Neuroimaging patterns have been mapped for a few isolated genes, chosen based on their connection with a clinical disorder. Here we propose an approach that allows an unrestricted discovery of the genetic basis of a neuroimaging phenotype in the normal human brain. The essential components are a subject population that is composed of relatives and selection of a neuroimaging phenotype that is reproducible within an individual and similar between relatives but markedly variable across a population. Our present combined magnetoencephalography and genome-wide linkage study in 212 healthy siblings demonstrates that auditory cortical activation strength is highly heritable and, specifically in the right hemisphere, regulated oligogenically with linkages to chromosomes 2q37, 3p12, and 8q24. The identified regions delimit as candidate genes TRAPPC9, operating in neuronal differentiation, and ROBO1, regulating projections of thalamocortical axons. Identification of normal genetic variation underlying neurophysiological phenotypes offers a non-invasive platform for an in-depth, concerted capitalization of molecular and neuroimaging levels in exploring neural function.

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Hemispheric asymmetries in language-related pathways: A combined functional MRI and tractography study

Cited by 376 publications

References 58 publications

Symmetries in human brain language pathways correlate with verbal recall

Symmetries in human brain language pathways correlate with verbal recall

Colateralization of Broca’s area and the visual word form area in left-handers: fMRI evidence

Genome-Wide Linkage Analysis of Human Auditory Cortical Activation Suggests Distinct Loci on Chromosomes 2, 3, and 8

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