scholarly journals Cerebral Lateralization of Frontal Lobe Language Processes and Lateralization of the Posterior Visual Word Processing System

2008 ◽  
Vol 20 (4) ◽  
pp. 672-681 ◽  
Author(s):  
Qing Cai ◽  
Michal Lavidor ◽  
Marc Brysbaert ◽  
Yves Paulignan ◽  
Tatjana A. Nazir
Keyword(s):  
Frontal Lobe ◽  
Left Hemisphere ◽  
Language Production ◽  
Word Processing ◽  
Right Hemisphere ◽  
Alternative Hypothesis ◽  
Visual Word ◽  
Related Potentials ◽  
Hemisphere Dominance ◽  
Visual Word Processing

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.

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
Keyword(s):  
San Francisco ◽  
Left Hemisphere ◽  
Language Production ◽  
Right Hemisphere ◽  
General Pattern ◽  
Hemispheric Dominance ◽  
Precentral Gyrus ◽  
Language Dominance ◽  
Speech Mapping ◽  
Hemisphere Dominance

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.

scholarly journals The contribution of phonological information to visual word recognition: Evidence from Chinese Phonetic Radicals

2020 ◽  
Author(s):  
Xiaodong Liu ◽  
Luc Vermeylen ◽  
David Wisniewski ◽  
Marc Brysbaert
Keyword(s):  
Visual Cortex ◽  
Word Recognition ◽  
Visual Word Recognition ◽  
Language Production ◽  
Word Processing ◽  
Right Hemisphere ◽  
Visual Word ◽  
Target Color ◽  
Chinese Characters ◽  
Phonological Information

Lateralization is a critical characteristic of language production and also plays a role in visual word recognition. However, the neural mechanisms underlying the interactions between visual input and spoken word representations are still unclear. We investigated the contribution of sub-lexical phonological information in visual word processing by exploiting the fact that Chinese characters can contain phonetic radicals in either the left or right half of the character. FMRI data were collected while 39 Chinese participants read words in search for target color words. On the basis of whole-brain analysis and three laterality analyses of regions of interest, we argue that visual information from centrally presented Chinese characters is split in the fovea and projected to the contralateral visual cortex, from which phonological information can be extracted rapidly if the character contains a phonetic radical. Extra activation, suggestive of more effortful processing, is observed when the phonetic radical is situated in the left half of the character and therefore initially sent to the visual cortex in the right hemisphere that is less specialized for language processing. Our results are in line with the proposal that phonological information helps written word processing by means of top-down feedback.

Role of the Right and Left Hemispheres in Recovery of Function during Treatment of Intention in Aphasia

2005 ◽  
Vol 17 (3) ◽  
pp. 392-406 ◽  
Author(s):  
Bruce Crosson ◽  
Anna Bacon Moore ◽  
Kaundinya Gopinath ◽  
Keith D. White ◽  
Christina E. Wierenga ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Frontal Lobe ◽  
Left Hemisphere ◽  
Language Production ◽  
Right Hemisphere ◽  
Recovery Of Function ◽  
Pre Treatment ◽  
The Right ◽  
Almost All ◽  
Production Mechanisms

Two patients with residual nonfluent aphasia after ischemic stroke received an intention treatment that was designed to shift intention and language production mechanisms from the frontal lobe of the damaged left hemisphere to the right frontal lobe. Consistent with experimental hypotheses, the first patient showed improvement on the intention treatment but not on a similar attention treatment. In addition, in keeping with experimental hypotheses, the patient showed a shift of activity to right presupplementary motor area and the right lateral frontal lobe from pre-to post-intention treatment functional magnetic resonance imaging (fMRI) of language production. In contrast, the second patient showed improvement on both the intention and attention treatments. During pre-treatment fMRI, she already showed lateralization of intention and language production mechanisms to the right hemisphere that continued into post-intention treatment imaging. From pre-to post-treatment fMRI of language production, both patients demonstrated increased activity in the posterior perisylvian cortex, although this activity was lateralized to left-hemisphere language areas in the second but not the first patient. The fact that the first patient's lesion encompassed almost all of the dominant basal ganglia and thalamus whereas the second patient's lesion spared these structures suggests that the dominant basal ganglia could play a role in spontaneous reorganization of language production functions to the right hemisphere. Implications regarding the theoretical framework for the intention treatment are discussed.

scholarly journals How do bilinguals control their use of languages?

2002 ◽  
Vol 5 (3) ◽  
pp. 214-215 ◽  
Author(s):  
Ardi Roelofs
Keyword(s):  
Word Recognition ◽  
Visual Word Recognition ◽  
Word Processing ◽  
Task Demands ◽  
Visual Word ◽  
Design Decisions ◽  
Processing Component ◽  
Visual Word Processing ◽  
New Processing

Dijkstra and Van Heuven sketch the BIA+ model for visual word processing in bilinguals. BIA+ differs in a number of respects from its predecessor, BIA, the leading implemented model of bilingual visual word recognition. Notably, BIA+ contains a new processing component that deals with task demands. BIA+ has not been computationally implemented yet and design decisions still need to be taken. In this commentary, I outline a proposal for modeling the control of tasks in BIA+.

Brain Activation Connected with Visual Word Processing in Korean Language

2008 ◽  
pp. 813-816
Author(s):  
Hyojeong Sohn ◽  
Sung Bum Pyun ◽  
Jaebum Jung ◽  
Hui-jin Song ◽  
Yongmin Chang ◽  
...  
Keyword(s):  
Word Processing ◽  
Brain Activation ◽  
Visual Word ◽  
Korean Language ◽  
Visual Word Processing
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