Homotopic organization of essential language sites in right and bilateral cerebral hemispheric dominance

2011 ◽  
Vol 114 (4) ◽  
pp. 893-902 ◽  
Author(s):  
Edward F. Chang ◽  
Doris D. Wang ◽  
David W. Perry ◽  
Nicholas M. Barbaro ◽  
Mitchel S. Berger

Object Language dominance in the right hemisphere is rare. Therefore, the organization of essential language sites in the dominant right hemisphere is unclear, especially compared with cases involving the more prevalent left dominant hemisphere. Methods The authors reviewed the medical records of 15 patients who underwent awake craniotomy for tumor or epilepsy surgery and speech mapping of right hemisphere perisylvian language areas at the University of California, San Francisco. All patients were determined to have either complete right-sided or bilateral language dominance by preoperative Wada testing. Results All patients but one were left-handed. Of more than 331 total stimulation sites, 27 total sites were identified as essential for language function (14 sites for speech arrest/anarthria; 12 for anomia; and 1 for alexia). While significant interindividual variability was observed, the general pattern of language organization was similar to classic descriptions of frontal language production and posterior temporal language integration for the left hemisphere. Speech arrest sites were clustered in the ventral precentral gyrus and pars opercularis. Anomia sites were more widely distributed, but were focused in the posterior superior and middle temporal gyri as well as the inferior parietal gyrus. One alexia site was found over the superior temporal gyrus. Face sensory and motor cortical sites were also identified along the ventral sensorimotor strip. The prevalence and specificity of essential language sites were greater in unilateral right hemisphere–dominant patients, compared with those with bilateral dominance by Wada testing. Conclusions The authors' results suggest that the organization of language in right hemisphere dominance mirrors that of left hemisphere dominance. Awake speech mapping is a safe and reliable surgical adjunct in these rare clinical cases and should be done in the setting of right hemisphere dominance to avoid preventable postoperative aphasia.

2008 ◽  
Vol 20 (4) ◽  
pp. 672-681 ◽  
Author(s):  
Qing Cai ◽  
Michal Lavidor ◽  
Marc Brysbaert ◽  
Yves Paulignan ◽  
Tatjana A. Nazir

The brain areas involved in visual word processing rapidly become lateralized to the left cerebral hemisphere. It is often assumed this is because, in the vast majority of people, cortical structures underlying language production are lateralized to the left hemisphere. An alternative hypothesis, however, might be that the early stages of visual word processing are lateralized to the left hemisphere because of intrinsic hemispheric differences in processing low-level visual information as required for distinguishing fine-grained visual forms such as letters. If the alternative hypothesis was correct, we would expect posterior occipito-temporal processing stages still to be lateralized to the left hemisphere for participants with right hemisphere dominance for the frontal lobe processes involved in language production. By analyzing event-related potentials of native readers of French with either left hemisphere or right hemisphere dominance for language production (determined using a verb generation task), we were able to show that the posterior occipito-temporal areas involved in visual word processing are lateralized to the same hemisphere as language production. This finding could suggest top-down influences in the development of posterior visual word processing areas.


Author(s):  
L Gould ◽  
M Kelly ◽  
C Ekstrand ◽  
T Ellchuk ◽  
R Borowsky

Background: Language mapping is a key goal in neurosurgical planning. With the discontinuation of the Wada test in Canada, neurosurgeons often rely on fMRI and intraoperative techniques for determining language lateralization. Recent studies have also evaluated the utility of diffusion tensor imaging (DTI) for preoperative language lateralization, but further research is needed to confirm its efficacy. We report a patient with a left frontal AVM. fMRI and DTI was used to localize language and motor functioning. Methods: The tasks included word reading, picture naming, pseudohomophones (e.g., dawg) and semantic questions. All fMRI analyses were performed using BrainVoyager. Tensors were tracked from 30-direction diffusion MR images using DSI-Studio. Results: The fMRI results revealed consistent Broca’s and Wernicke’s areas, confirming left hemisphere dominance. There was also a region of activation in the precentral gyrus near the surgical resection. The results were loaded onto the neuronavigation system to help determine safe surgical margins. The DTI results revealed that the left arcuate and uncinate -fasciculus had three times more tracts than the right hemisphere, further supporting left hemisphere dominance. Conclusions: This case highlights the value of a combined, multimodal approach for preoperative language localization, which will further enhance surgical safety by helping preserve regions for essential brain functions.


1977 ◽  
Vol 42 (1) ◽  
pp. 106-112 ◽  
Author(s):  
Robert T. Wertz ◽  
Bernard Messert ◽  
Michael Collins ◽  
Jay C. Rosenbek ◽  
Chun C. Kao

This paper reports a case of surgical removal of a left-hemisphere arteriovenous malformation (AVM) in a left-handed adult without subsequent speech or language deficit. Preoperative intracarotid amobarbital testing indicated right-hemisphere language dominance. Our patient demonstrated no language involvement prior to or following surgery. We speculate the congenital nature of a left-hemisphere AVM may dictate right-hemisphere language dominance, thereby explaining the lack of residuals following removal of AVMs in left-hemisphere speech and motor areas.


2011 ◽  
Vol 33 (3) ◽  
pp. 623-641 ◽  
Author(s):  
XIANGHUA WU ◽  
JUNG-YUEH TU ◽  
YUE WANG

ABSTRACTThe theoretical framework of this study is based on the prevalent debate of whether prosodic processing is influenced by higher level linguistic-specific circuits or reflects lower level encoding of physical properties. Using the dichotic listening technique, the study investigates the hemispheric processing of Japanese pitch accent by native Japanese listeners and two groups of nonnative listeners with no prior pitch accent experience but differing in their native language experience with linguistic pitch: native listeners of Mandarin (a tone language with higher linguistic functional use of pitch) and native listeners of English (a stress language with lower functional use of pitch). The overall results reveal that, for both native and nonnative listeners, the processing of Japanese pitch accent is less lateralized (compared to lexical tone processing, which has been found to be a left hemisphere property). However, detailed analysis with individual pitch accents across groups shows a right hemisphere preference for processing the high–accent–low (H*L) pattern, a left hemisphere preference for LH*, and no hemisphere dominance for LH, indicating a significant reliance on the acoustic cues. These patterns are particularly prominent with the English listeners who are least experienced with linguistic pitch. Together, the findings suggest an interplay of linguistic and acoustic aspects in the processing of Japanese pitch accent by native and nonnative listeners.


1995 ◽  
Vol 6 (3) ◽  
pp. 157-164 ◽  
Author(s):  
Janet Metcalfe ◽  
Margaret Funnell ◽  
Michael S. Gazzaniga

Six experiments explored hemispheric memory differences in a patient who had undergone complete corpus callosum resection The right hemisphere was better able than the left to reject new events similar to originally presented materials of several types, including abstract visual forms, faces, and categorized lists of words Although the left hemisphere is capable of mental manipulation, imagination, semantic priming, and complex language production, these functions are apparently linked to memory confusions—confusions less apparent in the more literal right hemisphere Differences between the left and right hemispheres in memory for new schematically consistent or categorically related events may provide a source of information allowing people to distinguish between what they actually witnessed and what they only inferred


2021 ◽  
pp. 1-11
Author(s):  
Monika M. Połczyńska ◽  
Lilian Beck ◽  
Taylor Kuhn ◽  
Christopher F. Benjamin ◽  
Timothy K. Ly ◽  
...  

OBJECTIVE Brain tumors located close to the language cortex may distort functional MRI (fMRI)–based estimates of language dominance. The nature of this distortion, and whether this is an artifact of numerous confounders, remains unknown. The authors hypothesized tumor bias based on laterality estimates independent of confounders and that the effects are the greatest for tumors proximal to Broca's area. METHODS To answer this question, the authors reviewed more than 1113 patients who underwent preoperative fMRI to match samples on 11 known confounders (tumor location, size, type, and grade; seizure history; prior neurosurgery; aphasia presence and severity; and patient age, sex, and handedness). The samples included 30 patients with left hemisphere tumors (15 anterior and 15 posterior) and 30 with right hemisphere tumors (15 anterior and 15 posterior), thus totaling 60 patients (25 women; 18 left-handed and 4 ambidextrous; mean age 47 [SD 14.1] years). Importantly, the authors matched not only patients with left and right hemisphere tumors but also those with anterior and posterior tumors. Standard fMRI laterality indices (LIs) were calculated using whole-brain and region of interest (ROI) approaches (Broca's and Wernicke's areas). RESULTS Tumors close to Broca's area in the left hemisphere decreased LIs independently of known confounders. At the whole-brain level, this appeared to reflect a decrease in LI values in patients with left anterior tumors compared with patients with right anterior tumors. ROI analysis replicated these findings. Broca's area LIs were significantly lower (p = 0.02) in patients with left anterior tumors (mean LI 0.28) when compared with patients with right anterior tumors (mean LI 0.70). Changes in Wernicke's area–based LIs did not differ as a function of the tumor hemisphere. Therefore, in patients with left anterior tumors, it is essential to assess language laterality using left posterior ROIs. In all remaining tumor groups (left posterior tumors and right hemisphere tumors), language laterality derived from the anterior language ROI was the most robust measure of language dominance. CONCLUSIONS Patients with tumors close to Broca's area showed more bilateral fMRI language maps independent of known confounders. The authors caution against the assumption that this reduced language laterality suggests no or little risk to language function following tumor resection in the left inferior frontal gyrus. Their results address how to interpret fMRI data for neurosurgical purposes, along with theoretical questions of contralesional functional compensation and disinhibition.


1993 ◽  
Vol 77 (3_suppl) ◽  
pp. 1299-1308 ◽  
Author(s):  
Peter Brugger ◽  
Alex Gamma ◽  
René Muri ◽  
Markus Schafer ◽  
Kirsten I. Taylor

30 right-handed subjects were given a lateralized tachistoscopic lexical-decision task. Subjects' belief in extrasensory perception (ESP) was assessed with a single six-point scale; 16 subjects were designated as believers in ESP and 14 subjects as nonbelievers. Believers in ESP did not exhibit a hemispheric asymmetry for the task while nonbelievers exhibited the expected right visual-field/left-hemisphere dominance documented in the literature. Believers' lack of asymmetry was not caused by an impaired left-hemisphere performance but rather by a significantly enhanced lexical-decision accuracy in the left visual field/right hemisphere compared to nonbelievers. These results are compatible with previous studies indicating a correlation between belief in ESP and a bias for right-hemisphere processing. Moreover, the results are relevant for a discussion of an association between paranormal beliefs and schizotypy: highly schizotypal individuals are not only particularly prone to believe in ESP but are also known to show an attenuation of hemispheric asymmetries in lateralized verbal tasks due to an enhanced contribution of the right hemisphere. We suggest that the neurological basis of delusion-like beliefs may involve a release of right-hemisphere function from left-hemisphere control and sketch the focus of research for a future “neuropsychology of belief.”


Neurosurgery ◽  
2000 ◽  
Vol 47 (3) ◽  
pp. 562-570 ◽  
Author(s):  
Eric M. Vikingstad ◽  
Yue Cao ◽  
Ajith J. Thomas ◽  
Alex F. Johnson ◽  
Ghaus M. Malik ◽  
...  

ABSTRACT OBJECTIVE In 90% of normal subjects, the left hemisphere is dominant for language function. We investigated whether congenital lesions of the left perisylvian regions altered cortical language representation in right-handed individuals. METHODS Using functional magnetic resonance imaging, we studied language hemispheric dominance in five right-handed adult patients with congenitally acquired arteriovenous malformations (AVMs) originating from left hemispheric cortical language regions. The AVMs had not caused neurological symptoms during early development, but patients presented as adults with migraine, seizure, or minor hemorrhage. Results obtained from the AVM patients were contrasted to those from right-handed brain-injured stroke patients recovering from aphasia and to those from right-handed normal subjects. RESULTS During silent picture naming and verb generation tasks, cortical language networks lateralized primarily to the right hemisphere in the AVM group, compared with the left hemisphere in the normal group. This right hemisphere-shifted language network in the AVM group exceeded the shifts toward right hemispheric dominance found in the stroke group. CONCLUSION Patients with AVMs affecting the left perisylvian regions recruited the right hemisphere into language processing networks during early development, presumably in response to congenitally aberrant circulation. This early right hemisphere recruitment in the AVM patients exceeded the similar process in the brains of stroke patients whose left cortical language networks were damaged in adulthood. Our data provide evidence of effective plasticity in the developing human brain compared with the mature brain response to injury. Knowledge of cortical language representation should assist presurgical planning in patients with developmental anomalies affecting apparently language-dominant brain regions.


2013 ◽  
Vol 54 (1) ◽  
pp. 91-98
Author(s):  
Andrej Šafhalter ◽  
Srečko Glodež ◽  
Karin Bakračevič Vukman

The progress of neuroscience and the understanding of children's styles of thinking are opening up new teaching styles that take into account differences in individual cognitive perception. Students can be classified into three distinctive perceptive types, according to the pronounced activity of one cerebral hemisphere in their thinking and information processing: left-hemisphere, right-hemisphere, and integrative type that does not exhibit a considerable dominance of one particular hemisphere. The purpose of the research was to establish differences in the 3D modeling encouraged progression of spatial ability between the left-hemisphere, right-hemisphere and integrative types of students. Computerized 3D modeling employed during technical extra-curricular activity in lower secondary school (grades 6 to 9) may affect the spatial ability of students, which according to other studies, appears to be predominantly connected with the right brain hemisphere. Research was conducted among a variety of lower secondary school students across Slovenia aged 11 – 15 years. Data on spatial ability and its development was collected using a hybrid spatial intelligence test conducted on two separate occasions, while assessment of the learning perception type of students – depending on hemispheric dominance – was obtained using a self-evaluation questionnaire. The 3D modeling of technical objects and objects drawn in orthographic or isometric projection was done with the software Trimble SketchUp. Key words: cognitive development, 3D modeling, hemispheric dominance, spatial ability.


Sign in / Sign up

Export Citation Format

Share Document