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

Haegen, Lise Van der; Cai, Qing; Brysbaert, Marc

doi:10.1016/j.bandl.2011.11.004

Cited by 74 publications

(70 citation statements)

References 53 publications

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“…Because the STS is at the heart of the human communication system, we first investigated whether the STAP is affected by language dominance. In particular, two groups of 17 young adults with either left or right cerebral hemisphere dominance for language, matched in age and handedness (24), were studied. In each group, permutation tests revealed asymmetrical segments along the sulcus which overlapped with the STAP region.…”

Section: Resultsmentioning

confidence: 99%

New human-specific brain landmark: The depth asymmetry of superior temporal sulcus

Leroy

Cai

Bogart³

et al. 2015

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

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Identifying potentially unique features of the human cerebral cortex is a first step to understanding how evolution has shaped the brain in our species. By analyzing MR images obtained from 177 humans and 73 chimpanzees, we observed a human-specific asymmetry in the superior temporal sulcus at the heart of the communication regions and which we have named the "superior temporal asymmetrical pit" (STAP). This 45-mm-long segment ventral to Heschl's gyrus is deeper in the right hemisphere than in the left in 95% of typical human subjects, from infanthood till adulthood, and is present, irrespective of handedness, language lateralization, and sex although it is greater in males than in females. The STAP also is seen in several groups of atypical subjects including persons with situs inversus, autistic spectrum disorder, Turner syndrome, and corpus callosum agenesis. It is explained in part by the larger number of sulcal interruptions in the left than in the right hemisphere. Its early presence in the infants of this study as well as in fetuses and premature infants suggests a strong genetic influence. Because this asymmetry is barely visible in chimpanzees, we recommend the STAP region during midgestation as an important phenotype to investigate asymmetrical variations of gene expression among the primate lineage. This genetic target may provide important insights regarding the evolution of the crucial cognitive abilities sustained by this sulcus in our species, namely communication and social cognition.ince Geschwind and Levitsky's (1) first attempt to identify a specifically human cortical landmark, the identification of unique features of the human brain that might explain the cognitive success of the human species has remained elusive so that anatomical targets still do not exist to inform the search for genetic mutations contributing to the human cognitive phenotype. Because hemispheric asymmetry and language processing are fundamental human traits, the perisylvian language areas have been especially scrutinized for such markers, but until now none has been forthcoming. In particular, the reported asymmetries in the planum temporale and the inferior frontal region are not as robust as initially thought (1-3) and also are observed, albeit often less marked, in other primates (4). However, we show here that asymmetry of the superior temporal sulcus (STS), at the core of the human communication system, represents a species-specific perisylvian anatomical marker. This finding is consistent with functional brain imaging studies that have emphasized the importance of STS not only for language processing in the left hemisphere but also for social communication in the right hemisphere (5, 6). Notably, in the left hemisphere a hierarchy of areas sensitive to increased levels of acoustical complexity is observed along superior temporal regions and become specifically linguistic along the STS (7, 8), whereas in the right hemisphere the presence of areas involved in voice and face recognition, gaze perception, and theory o...

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Section: Resultsmentioning

confidence: 99%

New human-specific brain landmark: The depth asymmetry of superior temporal sulcus

Leroy

Cai

Bogart³

et al. 2015

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

Self Cite

164

150

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“…However, 31 participants showed bilateral patterns for word reading -that is, there was no clear activation dominance of the ventral occipitotemporal cortex when reading words -and strongly lateralized activation for speech production. Moreover, three participants processed speech and reading predominantly in opposite hemispheres 79 . These findings suggest that cerebral lateralization can differ for distinct sub-processes of a given cognitive function, at least in the case of the language system.…”

Section: Cerebral Lateralizationmentioning

confidence: 99%

“…One important study compared the direction and degree of speech and reading lateralization in a cohort of 57 left-handers 79 . First, a lateralization index for speech production was calculated on the basis of activity in the left and right inferior frontal gyrus (that is, pars opercularis and triangularis) during a word-generation task.…”

Section: Cerebral Lateralizationmentioning

confidence: 99%

On the other hand: including left-handers in cognitive neuroscience and neurogenetics

et al. 2014

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Left-handers are often excluded from study cohorts in neuroscience and neurogenetics in order to reduce variance in the data. However, recent investigations have shown that the inclusion or targeted recruitment of left-handers can be informative in studies on a range of topics, such as cerebral lateralization and the genetic underpinning of asymmetrical brain development. Left-handed individuals represent a substantial portion of the human population and therefore left-handedness falls within the normal range of human diversity; thus, it is important to account for this variation in our understanding of brain functioning. We call for neuroscientists and neurogeneticists to recognize the potential of studying this often-discarded group of research subjects

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“…These regions represent the Broca area for most right-handed and the majority of left-handed people. 25 We suggest that the specific brain regions identified by this study in association with the C9orf72 genotype should affect the design of future neuropsychological batteries by providing the anatomic bases for targeted assessments, such as in-depth assessments of language domains. Similarly, based on the consistent bilateral fusiform gyrus involvement, tests of face and word recognition should be considered in addition to the widely used executive tests.…”

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confidence: 99%

Multiparametric MRI study of ALS stratified for the C9orf72 genotype

et al. 2013

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Objective: To describe the patterns of cortical and subcortical changes in amyotrophic lateral sclerosis (ALS) stratified for the C9orf72 genotype.Methods: A prospective, single-center, single-protocol, gray and white matter magnetic resonance case-control imaging study was undertaken with 30 C9orf72-negative patients with ALS, 9 patients with ALS carrying the C9orf72 hexanucleotide repeat expansion, and 44 healthy controls. Tractbased spatial statistics of multiple white matter diffusion parameters, cortical thickness measurements, and voxel-based morphometry analyses were carried out. All patients underwent comprehensive genetic and neuropsychological profiling.Results: A congruent pattern of cortical and subcortical involvement was identified in those with the C9orf72 genotype, affecting fusiform, thalamic, supramarginal, and orbitofrontal regions and the Broca area. White matter abnormalities in the C9orf72-negative group were relatively confined to corticospinal and cerebellar pathways with limited extramotor expansion. The body of the corpus callosum and superior motor tracts were affected in both ALS genotypes. Conclusions: Extensive cortical and subcortical frontotemporal involvement was identified in associ-ation with the C9orf72 genotype, compared to the relatively limited extramotor pathology in patients with C9orf72-negative ALS. The distinctive, genotype-specific pathoanatomical patterns are consistent with the neuropsychological profile of the 2 ALS cohorts. Our findings suggest that previously described extramotor changes in ALS could be largely driven by those with the C9orf72 genotype. GLOSSARY ALS 5 amyotrophic lateral sclerosis; C9neg 5 patients with amyotrophic lateral sclerosis not carrying the hexanucleotide repeat expansion on C9orf72; C9pos 5 patients with amyotrophic lateral sclerosis carrying the hexanucleotide repeat expansion on C9orf72 ( .30 repeats); DTI 5 diffusion tensor imaging; FA 5 fractional anisotropy; FDR 5 false discovery rate; FOV 5 field of view; FTD 5 frontotemporal dementia; HC 5 healthy controls; MD 5 mean diffusivity; RD 5 radial diffusivity; TBSS 5 tract-based spatial statistics; TE 5 echo time; TFCE 5 threshold-free cluster enhancement; TR 5 repetition time; VBM 5 voxel-based morphometry.

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

Cited by 74 publications

References 53 publications

New human-specific brain landmark: The depth asymmetry of superior temporal sulcus

New human-specific brain landmark: The depth asymmetry of superior temporal sulcus

On the other hand: including left-handers in cognitive neuroscience and neurogenetics

Multiparametric MRI study of ALS stratified for the C9orf72 genotype

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