1
|
Şahin MH, Akyüz ME, Karadağ MK, Yalçın A. Supramarginal Gyrus and Angular Gyrus Subcortical Connections: A Microanatomical and Tractographic Study for Neurosurgeons. Brain Sci 2023; 13:brainsci13030430. [PMID: 36979240 PMCID: PMC10046402 DOI: 10.3390/brainsci13030430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
Background and Objectives: This article aims to investigate the subcortical microanatomy of the supramarginal gyrus (SMG) and angular gyrus (AnG) using a microfiber dissection technique and diffusion tensor imaging (DTI)/fiber tractography (FT). The cortical and subcortical structures of this region are highly functional, and their lesions often present clinically. For this reason, the possibility of post-surgical deficits is high. We focused on the supramarginal gyrus and the angular gyrus and reviewed their anatomy from a topographic, functional and surgical point of view, and aimed to raise awareness especially for neurosurgeons. Methods: Four previously frozen, formalin-fixed human brains were examined under the operating microscope using the fiber dissection technique. Four hemispheres were dissected from medial to lateral under the surgical microscope. Brain magnetic resonance imaging (MRI) of 20 healthy adults was examined. Pre-central and post-central gyrus were preserved to achieve topographic dominance in dissections of brain specimens. Each stage was photographed. Tractographic brain magnetic resonance imaging of 10 healthy adults was examined radiologically. Focusing on the supramarginal and angular gyrus, the white matter fibers passing under this region and their intersection areas were examined. These two methods were compared anatomically from the lateral view and radiologically from the sagittal view. Results: SMG and AnG were determined in brain specimens. The pre-central and post-central gyrus were topographically preserved. The superior and medial temporal gyrus, and inferior and superior parietal areas were decorticated from lateral to medial. U fibers, superior longitudinal fasciculus II (SLF II), superior longitudinal fasciculus III (SLF III), arcuat fasciculus (AF) and middle longitudinal fasciculus (MdLF) fiber groups were shown and subcortical fiber structures belonging to these regions were visualized by the DTI/FT method. The subcortical fiber groups under the SMG and the AnG were observed anatomically and radiologically to have a dense and complex structure. Conclusions: Due to the importance of the subcortical connections of SMG and AnG on speech function, tumoral lesions and surgeries of this region are of particular importance. The anatomical architecture of the complex subcortical structure, which is located on the projection of the SMG and AnG areas, was shown with a DTI/FT examination under a topographic dominance, preserving the pre-central and post-central gyrus. In this study, the importance of the anatomical localization, connections and functions of the supramarginal and angular gyrus was examined. More anatomical and radiological studies are needed to better understand this region and its connections.
Collapse
|
2
|
Concordance of Lateralization Index for Brain Asymmetry Applied to Identify a Reliable Language Task. Symmetry (Basel) 2023. [DOI: 10.3390/sym15010193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
How can we determine which language task is relevant for examining functional hemispheric asymmetry? A problem in measuring brain asymmetry using functional magnetic resonance imaging lies in the uncertain reliability of the computed index regarding the “true” asymmetry degree. Strictly speaking, the results from the Wada test or direct cortical stimulation cannot be an exact “ground truth”, specifically for the degree of asymmetry. Therefore, we developed a method to evaluate task performance using reproducibility independent of the phenomenon of functional lateralization. Kendall’s coefficient of concordance (W) was used as the statistical measure. The underlying idea was that although various algorithms to compute the lateralization index show considerably different index values for the same data, a superior language task would reproduce similar individual ranking sequences across the algorithms; the high reproducibility of rankings across various index types would indicate a reliable task to investigate functional asymmetry regardless of index computation algorithms. Consequently, we found specificity for brain locations; a verb-generation task demonstrated the highest concordance across index types along with sufficiently high index values in the inferior frontal gyrus, whereas a narration–listening task demonstrated the highest concordance in the posterior temporo-parietal junction area.
Collapse
|
3
|
Matsuo K, Kono K, Yasui-Furukori N, Shimoda K, Kaji Y, Akiyama K. HomotopicLI: Rationale, characteristics, and implications of a new threshold-free lateralization index of functional magnetic resonance imaging. Laterality 2022; 27:513-543. [PMID: 35948519 DOI: 10.1080/1357650x.2022.2109655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The reliable preoperative estimation of brain hemispheric asymmetry may be achieved through multiple lateralization indices using functional magnetic resonance imaging. Adding to our previously developed AveLI, we devised a novel threshold-free lateralization index, HomotopicLI, which computes a basic formula, (Left - Right) / (Left + Right), using voxel values of pairs located symmetrically in relation to the midsagittal line as the terms Left and Right, and averages them within the regions-of-interest. The study aimed to evaluate HomotopicLI before clinical applications. Data were collected from 56 healthy participants who performed four language tasks. We compared seven index types, including HomotopicLI, AveLI, and BaseLI; BaseLI was calculated using the sums of voxel values as the terms. Contrary to our expectations, HomotopicLI performed similarly to AveLI but better than BaseLI in detecting right dominance. A detailed analysis of unilaterally activated voxels of the homotopic pairs revealed that unilateral activation occurred more frequently on the right than on the left when HomotopicLI indicated right dominance. The voxel values during right unilateral activation were smaller than those in the left, causing right dominances in the homotopic pairs by HomotopicLI. These unique features provide an advantage in detecting residual, compensative functions spreading weakly in the non-dominant hemisphere.
Collapse
Affiliation(s)
- Kayako Matsuo
- Center for Research Collaboration and Support, Dokkyo Medical University School of Medicine, Tochigi, Japan.,Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Japan
| | - Kenta Kono
- Dokkyo Medical University School of Medicine, Tochigi, Japan
| | - Norio Yasui-Furukori
- Department of Psychiatry, Dokkyo Medical University School of Medicine, Tochigi, Japan
| | - Kazutaka Shimoda
- Department of Psychiatry, Dokkyo Medical University School of Medicine, Tochigi, Japan
| | - Yasushi Kaji
- Department of Radiology, Dokkyo Medical University School of Medicine, Tochigi, Japan
| | - Kazufumi Akiyama
- Department of Biological Psychiatry and Neuroscience, Dokkyo Medical University School of Medicine, Tochigi, Japan.,Kawada Hospital, Okayama, Japan
| |
Collapse
|
4
|
Intraoperative Neuromonitoring. Neurol Clin 2022; 40:375-389. [DOI: 10.1016/j.ncl.2021.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
5
|
Drane DL, Pedersen NP, Sabsevitz DS, Block C, Dickey AS, Alwaki A, Kheder A. Cognitive and Emotional Mapping With SEEG. Front Neurol 2021; 12:627981. [PMID: 33912122 PMCID: PMC8072290 DOI: 10.3389/fneur.2021.627981] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 03/04/2021] [Indexed: 02/05/2023] Open
Abstract
Mapping of cortical functions is critical for the best clinical care of patients undergoing epilepsy and tumor surgery, but also to better understand human brain function and connectivity. The purpose of this review is to explore existing and potential means of mapping higher cortical functions, including stimulation mapping, passive mapping, and connectivity analyses. We examine the history of mapping, differences between subdural and stereoelectroencephalographic approaches, and some risks and safety aspects, before examining different types of functional mapping. Much of this review explores the prospects for new mapping approaches to better understand other components of language, memory, spatial skills, executive, and socio-emotional functions. We also touch on brain-machine interfaces, philosophical aspects of aligning tasks to brain circuits, and the study of consciousness. We end by discussing multi-modal testing and virtual reality approaches to mapping higher cortical functions.
Collapse
Affiliation(s)
- Daniel L. Drane
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
- Emory Epilepsy Center, Atlanta, GA, United States
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, United States
| | - Nigel P. Pedersen
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
- Emory Epilepsy Center, Atlanta, GA, United States
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States
| | - David S. Sabsevitz
- Department of Psychology and Psychiatry, Mayo Clinic, Jacksonville, FL, United States
- Department of Neurological Surgery, Mayo Clinic, Jacksonville, FL, United States
| | - Cady Block
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
| | - Adam S. Dickey
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
| | - Abdulrahman Alwaki
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
| | - Ammar Kheder
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| |
Collapse
|
6
|
Labache L, Mazoyer B, Joliot M, Crivello F, Hesling I, Tzourio-Mazoyer N. Typical and atypical language brain organization based on intrinsic connectivity and multitask functional asymmetries. eLife 2020; 9:e58722. [PMID: 33064079 PMCID: PMC7605859 DOI: 10.7554/elife.58722] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 10/16/2020] [Indexed: 01/23/2023] Open
Abstract
Based on the joint investigation in 287 healthy volunteers (150 left-Handers (LH)) of language task-induced asymmetries and intrinsic connectivity strength of the sentence-processing supramodal network, we show that individuals with atypical rightward language lateralization (N = 30, 25 LH) do not rely on an organization that simply mirrors that of typical leftward lateralized individuals. Actually, the resting-state organization in the atypicals showed that their sentence processing was underpinned by left and right networks both wired for language processing and highly interacting by strong interhemispheric intrinsic connectivity and larger corpus callosum volume. Such a loose hemispheric specialization for language permits the hosting of language in either the left and/or right hemisphere as assessed by a very high incidence of dissociations across various language task-induced asymmetries in this group.
Collapse
Affiliation(s)
- Loïc Labache
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- Université de Bordeaux, Institut de Mathématiques de Bordeaux, UMR 5251BordeauxFrance
- Bordeaux INP, Institut de Mathématiques de Bordeaux, UMR 5251BordeauxFrance
- INRIA Bordeaux Sud-Ouest, Institut de Mathématiques de Bordeaux, UMR 5251, Contrôle de Qualité et Fiabilité DynamiqueTalenceFrance
| | - Bernard Mazoyer
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- Centre Hospitalier Universitaire de BordeauxBordeauxFrance
| | - Marc Joliot
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
| | - Fabrice Crivello
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
| | - Isabelle Hesling
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
| | - Nathalie Tzourio-Mazoyer
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
- CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d’Imagerie NeurofonctionnelleBordeauxFrance
| |
Collapse
|
7
|
Seghier ML. Categorical laterality indices in fMRI: a parallel with classic similarity indices. Brain Struct Funct 2019; 224:1377-1383. [DOI: 10.1007/s00429-019-01833-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/08/2019] [Indexed: 11/29/2022]
|
8
|
Drane DL, Pedersen NP. Knowledge of language function and underlying neural networks gained from focal seizures and epilepsy surgery. BRAIN AND LANGUAGE 2019; 189:20-33. [PMID: 30615986 PMCID: PMC7183240 DOI: 10.1016/j.bandl.2018.12.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 09/05/2018] [Accepted: 12/19/2018] [Indexed: 05/09/2023]
Abstract
The effects of epilepsy and its treatments have contributed significantly to language models. The setting of epilepsy surgery, which allows for careful pre- and postsurgical evaluation of patients with cognitive testing and neuroimaging, has produced a wealth of language findings. Moreover, a new wave of surgical interventions, including stereotactic laser ablation and radio frequency ablation, have contributed new insights and corrections to language models as they can make extremely precise, focal lesions. This review covers the common language deficits observed in focal dyscognitive seizure syndromes. It also addresses the effects of surgical interventions on language, and highlights insights gained from unique epilepsy assessment methods (e.g., cortical stimulation mapping, Wada evaluation). Emergent findings are covered including a lack of involvement of the hippocampus in confrontation word retrieval, possible roles for key white matter tracts in language, and the often-overlooked basal temporal language area. The relationship between language and semantic memory networks is also explored, with brief consideration given to the prevailing models of semantic processing, including the amodal Hub and distributed, multi-modal processing models.
Collapse
Affiliation(s)
- Daniel L Drane
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA; Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA; Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA.
| | - Nigel P Pedersen
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| |
Collapse
|
9
|
Seghier ML, Price CJ. Interpreting and Utilising Intersubject Variability in Brain Function. Trends Cogn Sci 2018; 22:517-530. [PMID: 29609894 PMCID: PMC5962820 DOI: 10.1016/j.tics.2018.03.003] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/30/2018] [Accepted: 03/07/2018] [Indexed: 11/30/2022]
Abstract
We consider between-subject variance in brain function as data rather than noise. We describe variability as a natural output of a noisy plastic system (the brain) where each subject embodies a particular parameterisation of that system. In this context, variability becomes an opportunity to: (i) better characterise typical versus atypical brain functions; (ii) reveal the different cognitive strategies and processing networks that can sustain similar tasks; and (iii) predict recovery capacity after brain damage by taking into account both damaged and spared processing pathways. This has many ramifications for understanding individual learning preferences and explaining the wide differences in human abilities and disabilities. Understanding variability boosts the translational potential of neuroimaging findings, in particular in clinical and educational neuroscience.
Collapse
Affiliation(s)
- Mohamed L Seghier
- Cognitive Neuroimaging Unit, Emirates College for Advanced Education, PO Box 126662, Abu Dhabi, United Arab Emirates.
| | - Cathy J Price
- Wellcome Centre for Human Neuroimaging, University College London, Institute of Neurology, WC1N 3BG, London, UK.
| |
Collapse
|
10
|
Połczyńska M, Kuhn T, You SC, Walshaw P, Curtiss S, Bookheimer S. Assessment of grammar optimizes language tasks for the intracarotid amobarbital procedure. Epilepsy Behav 2017; 76:89-100. [PMID: 28923498 DOI: 10.1016/j.yebeh.2017.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 07/24/2017] [Accepted: 08/14/2017] [Indexed: 11/16/2022]
Abstract
PURPOSE A previous study showed that assessment of language laterality could be improved by adding grammar tests to the recovery phase of the intracarotid amobarbital procedure (IAP) (Połczyńska et al. 2014). The aim of this study was to further investigate the extent to which grammar tests lateralize language function during the recovery phase of the IAP in a larger patient sample. METHODS Forty patients with drug-resistant epilepsy (14 females, thirty-two right-handed, mean age 38.5years, SD=10.6) participated in this study. On EEG, 24 patients had seizures originating in the left hemisphere (LH), 13 in the right hemisphere (RH), and 4 demonstrated mixed seizure origin. Thirty participants (75%) had bilateral injections, and ten (25%) had unilateral injections (five RH and five LH). Based on results from the encoding phase, we segregated our study participants to a LH language dominant and a mixed dominance group. In the recovery phase of the IAP, the participants were administered a new grammar test (the CYCLE-N) and a standard language test. We analyzed the laterality index measure and effect sizes in the two tests. KEY FINDINGS In the LH-dominant group, the CYCLE-N generated more profound language deficits in the recovery phase than the standard after injection to either hemisphere (p<0.001). At the same time, the laterality index for the grammar tasks was still higher than for the standard tests. Critically, the CYCLE-N administered in the recovery phase was nearly as effective as the standard tests given during the encoding phase. SIGNIFICANCE The results may be significant for individuals with epilepsy undergoing IAP. The grammar tests may be a highly efficient measure for lateralizing language function in the recovery phase.
Collapse
Affiliation(s)
- Monika Połczyńska
- UCLA Department of Psychiatry and Biobehavioral Sciences, Los Angeles, USA; Faculty of English, Adam Mickiewicz University, Poznań, Poland.
| | - Taylor Kuhn
- UCLA Department of Psychiatry and Biobehavioral Sciences, Los Angeles, USA.
| | - S Christine You
- UCLA Department of Psychiatry and Biobehavioral Sciences, Los Angeles, USA.
| | - Patricia Walshaw
- UCLA Department of Psychiatry and Biobehavioral Sciences, Los Angeles, USA.
| | | | - Susan Bookheimer
- UCLA Department of Psychiatry and Biobehavioral Sciences, Los Angeles, USA.
| |
Collapse
|
11
|
Zago L, Hervé PY, Genuer R, Laurent A, Mazoyer B, Tzourio-Mazoyer N, Joliot M. Predicting hemispheric dominance for language production in healthy individuals using support vector machine. Hum Brain Mapp 2017; 38:5871-5889. [PMID: 28868791 DOI: 10.1002/hbm.23770] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 07/27/2017] [Accepted: 08/08/2017] [Indexed: 01/16/2023] Open
Abstract
We used a Support Vector Machine (SVM) classifier to assess hemispheric pattern of language dominance of 47 individuals categorized as non-typical for language from their hemispheric functional laterality index (HFLI) measured on a sentence minus word-list production fMRI-BOLD contrast map. The SVM classifier was trained at discriminating between Dominant and Non-Dominant hemispheric language production activation pattern on a group of 250 participants previously identified as Typicals (HFLI strongly leftward). Then, SVM was applied to each hemispheric language activation pattern of 47 non-typical individuals. The results showed that at least one hemisphere (left or right) was found to be Dominant in every, except 3 individuals, indicating that the "dominant" type of functional organization is the most frequent in non-typicals. Specifically, left hemisphere dominance was predicted in all non-typical right-handers (RH) and in 57.4% of non-typical left-handers (LH). When both hemisphere classifications were jointly considered, four types of brain patterns were observed. The most often predicted pattern (51%) was left-dominant (Dominant left-hemisphere and Non-Dominant right-hemisphere), followed by right-dominant (23%, Dominant right-hemisphere and Non-Dominant left-hemisphere) and co-dominant (19%, 2 Dominant hemispheres) patterns. Co-non-dominant was rare (6%, 2 Non-Dominant hemispheres), but was normal variants of hemispheric specialization. In RH, only left-dominant (72%) and co-dominant patterns were detected, while for LH, all types were found, although with different occurrences. Among the 10 LH with a strong rightward HFLI, 8 had a right-dominant brain pattern. Whole-brain analysis of the right-dominant pattern group confirmed that it exhibited a functional organization strictly mirroring that of left-dominant pattern group. Hum Brain Mapp 38:5871-5889, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Laure Zago
- Université de Bordeaux, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France
| | - Pierre-Yves Hervé
- Université de Bordeaux, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France
| | - Robin Genuer
- Université de Bordeaux, ISPED, Centre INSERM U-1219, F-33000 Bordeaux, France.,INSERM, ISPED, Centre INSERM U-1219, F-33000 Bordeaux, France
| | - Alexandre Laurent
- Université de Bordeaux, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France
| | - Bernard Mazoyer
- Université de Bordeaux, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France
| | - Nathalie Tzourio-Mazoyer
- Université de Bordeaux, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France
| | - Marc Joliot
- Université de Bordeaux, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CNRS, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France.,CEA, Institut des Maladies Neurodégéneratives, UMR 5293, Groupe d'Imagerie Neurofonctionnelle, F-33000 Bordeaux, France
| |
Collapse
|
12
|
Alonso F, Sweet J, Miller J. Speech mapping using depth electrodes: The “electric Wada”. Clin Neurol Neurosurg 2016; 144:88-90. [DOI: 10.1016/j.clineuro.2016.03.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/13/2016] [Accepted: 03/18/2016] [Indexed: 10/22/2022]
|
13
|
Kendall DL, Minkina I, Bislick L, Grabowski TJ, Phatak V, Silkes JP, Ojemann JG. Language treatment prior to anterior temporal lobe surgery: Can naming skills be preserved? JOURNAL OF REHABILITATION RESEARCH AND DEVELOPMENT 2016; 53:813-826. [PMID: 28273323 DOI: 10.1682/jrrd.2014.12.0310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 12/01/2015] [Indexed: 11/05/2022]
Abstract
Epilepsy affects 1% of the general population and is highly prevalent among Veterans. The purpose of this phase I study was to investigate a presurgical linguistically distributed language treatment program that could potentially diminish effects of proper-name retrieval deficits following left anterior temporal lobe resection for intractable epilepsy. A single-subject multiple-baseline design was employed for three individuals with late-onset chronic left temporal lobe epilepsy. Word retrieval treatment was administered prior to anterior temporal lobe resection. The primary outcome measure was confrontation naming of proper nouns. Immediately posttreatment (before surgery), there was a positive effect for all trained stimuli in the form of improved naming as compared with pretreatment. In addition, trained stimuli were found to be better after surgery than they were at pretreatment baseline, which would not be expected had language treatment not been provided. This series of case studies introduces two fundamentally novel concept: that commonly occurring deficits associated with left temporal lobe epilepsy can be treated despite the presence of damaged neural tissue and that providing this treatment prior to surgery can lead to better preservation of language function after surgery than would be expected if the treatment were not provided.
Collapse
Affiliation(s)
- Diane L Kendall
- Department of Speech and Hearing Sciences, University of Washington, Seattle, WA.,Department of Veterans Affairs Puget Sound Health Care System, Seattle, WA
| | - Irene Minkina
- Department of Speech and Hearing Sciences, University of Washington, Seattle, WA
| | - Lauren Bislick
- Department of Speech and Hearing Sciences, University of Washington, Seattle, WA
| | - Thomas J Grabowski
- Integrated Brain Imaging Center, University of Washington, Seattle, WA.,Department of Radiology, University of Washington, Seattle, WA
| | - Vaishali Phatak
- Department of Neurology, University of Washington, Seattle, WA
| | - JoAnn P Silkes
- Department of Speech and Hearing Sciences, University of Washington, Seattle, WA
| | - Jeffrey G Ojemann
- Department of Neurological Surgery, University of Washington, Seattle, WA
| |
Collapse
|
14
|
Variation in homotopic areas' activity and inter-hemispheric intrinsic connectivity with type of language lateralization: an FMRI study of covert sentence generation in 297 healthy volunteers. Brain Struct Funct 2015; 221:2735-53. [PMID: 26013303 DOI: 10.1007/s00429-015-1068-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 05/20/2015] [Indexed: 10/23/2022]
Abstract
We investigated the regional correlates of differences in hemispheric lateralization in 297 healthy volunteers [including 153 left-handers (LH)] previously classified into three types of language lateralization according to their hemispheric functional lateralization index measured with fMRI during covert sentence production versus word list production (PRODSENT-LIST): 250 leftward asymmetrical Typicals, 10 rightward asymmetrical Strong-atypicals (only LH), and 37 Ambilaterals with weak lateralization. Using a functionally driven homotopic atlas (AICHA), we compared patterns of regional asymmetry during PRODSENT-LIST in these three groups. Among the 192 homotopic regions of interest (hROIs) of the AICHA atlas, 58 exhibited a significant effect of the type of lateralization on their BOLD signal variation during PRODSENT-LIST. The analyses of patterns of asymmetry of these 58 hROIs showed that (1) hROIs asymmetries in Strong-atypicals were significantly negatively correlated with those observed in Typicals, which indicates that their regional pattern of rightward asymmetries was comparable to the regional pattern of leftward language asymmetries of Typicals; (2) right- and left-handed Typicals had identical profiles, whereas left-handed Ambilaterals exhibited reduced leftward asymmetry as compared either to right-handed Ambilaterals or to Typicals. Moreover, left-handed Ambilaterals pattern of hROIs asymmetries significantly positively correlated with those of both Typicals and Strong-atypicals. In 291 of the participants, we tested the hypothesis that differences in language lateralization were associated with differences in inter-hemispheric connectivity during resting state by measuring their regional homotopic inter-hemispheric intrinsic connectivity coefficient (rHIICC) in 36 of the 58 hROIs known to be connected via the corpus callosum. Mean rHIICCs were negatively correlated with task-induced functional asymmetries, suggesting that enhanced inter-hemispheric cooperation at rest translates into increased inter-hemispheric cooperation during language production. In addition, the left-handed Ambilaterals exhibited a significantly larger rHIICC compared with right-handed Ambilaterals and Typicals, confirming a difference in inter-hemispheric organization in this group.
Collapse
|
15
|
Połczyńska MM, Benjamin CFA, Moseley BD, Walshaw P, Eliashiv D, Vigil C, Jones M, Bookheimer SY. Role of the Wada test and functional magnetic resonance imaging in preoperative mapping of language and memory: two atypical cases. Neurocase 2015; 21:707-20. [PMID: 25372664 DOI: 10.1080/13554794.2014.977300] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The Wada test is an invasive procedure used to determine cerebral memory and language dominance as well as risk of cognitive deficits following neurosurgery. However, the potential risks of Wada testing have led some to consider foregoing Wada testing in candidates for resective epilepsy surgery with right hemispheric seizure onset. We present two atypical cases in which the Wada test showed unexpected memory and language lateralization. These cases underscore the importance of functional magnetic resonance in which imaging and Wada examination in right-handed individuals even when the lesion would not suggest atypical language representation.
Collapse
Affiliation(s)
- Monika M Połczyńska
- a Department of Psychiatry and Biobehavioral Sciences , University of California , Los Angeles , CA , USA
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Chang EF, Raygor KP, Berger MS. Contemporary model of language organization: an overview for neurosurgeons. J Neurosurg 2014; 122:250-61. [PMID: 25423277 DOI: 10.3171/2014.10.jns132647] [Citation(s) in RCA: 237] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Classic models of language organization posited that separate motor and sensory language foci existed in the inferior frontal gyrus (Broca's area) and superior temporal gyrus (Wernicke's area), respectively, and that connections between these sites (arcuate fasciculus) allowed for auditory-motor interaction. These theories have predominated for more than a century, but advances in neuroimaging and stimulation mapping have provided a more detailed description of the functional neuroanatomy of language. New insights have shaped modern network-based models of speech processing composed of parallel and interconnected streams involving both cortical and subcortical areas. Recent models emphasize processing in "dorsal" and "ventral" pathways, mediating phonological and semantic processing, respectively. Phonological processing occurs along a dorsal pathway, from the posterosuperior temporal to the inferior frontal cortices. On the other hand, semantic information is carried in a ventral pathway that runs from the temporal pole to the basal occipitotemporal cortex, with anterior connections. Functional MRI has poor positive predictive value in determining critical language sites and should only be used as an adjunct for preoperative planning. Cortical and subcortical mapping should be used to define functional resection boundaries in eloquent areas and remains the clinical gold standard. In tracing the historical advancements in our understanding of speech processing, the authors hope to not only provide practicing neurosurgeons with additional information that will aid in surgical planning and prevent postoperative morbidity, but also underscore the fact that neurosurgeons are in a unique position to further advance our understanding of the anatomy and functional organization of language.
Collapse
Affiliation(s)
- Edward F Chang
- Department of Neurological Surgery, University of California, San Francisco, California
| | | | | |
Collapse
|
17
|
DuRousseau DR, Beeton TA. System Level spatial-frequency EEG changes coincident with a 90-day cognitive-behavioral therapy program for couples in relationship distress. Brain Imaging Behav 2014; 9:597-608. [PMID: 25274224 PMCID: PMC4575684 DOI: 10.1007/s11682-014-9319-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Evaluating relationship intervention programs traditionally involves the use of self-report surveys or observational studies to assess changes in behavior. Instead, to investigate intervention-related changes in behavior, our study evaluates spatial-frequency electroencephalography (EEG) patterns from the brains of couples participating in an Imago Relationship workshop and 12 weeks of group counseling sessions lasting approximately 90 days. This explorative study recorded 32-channel EEGs from nine committed distressed couples prior to, during and immediately following the Imago Relationship Therapy program. A repeated measures t-Test approach was applied to investigate if significant group level brain pattern changes could be identified in key resting state networks in the brains of the participants that could be correlated with changes in relationship outcome. The study results show that significant reductions in EEG power in the alpha2, beta3 and gamma bands were evident in the averaged brain activity in the pre-frontal, frontal and temporal-parietal cortices that are anatomically associated with the frontal executive, default mode and salience networks of the human brain. Our current understanding of system level neural connectivity and network dynamics strongly indicates that each of these systems is integrally required in learning and implementing a complex communication process taught in the Imago intervention. Thus, a high degree of hemispheric lateralization is consistent with our understanding of language function and mood regulation in the brain and is consistent with recent research into the use of resting frontal EEG asymmetry as an indicator of behavioral changes in distressed couples undergoing a program for relationship improvement. Although preliminary, these results further indicate that the EEG is an inexpensive and easily quantifiable measure, and possibly predictor, of behavioral changes in response to a cognitive behavioral intervention.
Collapse
Affiliation(s)
| | - Theresa A Beeton
- Loudoun Family and Relationship Counseling, Inc., Leesburg, VA, USA.
| |
Collapse
|
18
|
Mazoyer B, Zago L, Jobard G, Crivello F, Joliot M, Perchey G, Mellet E, Petit L, Tzourio-Mazoyer N. Gaussian mixture modeling of hemispheric lateralization for language in a large sample of healthy individuals balanced for handedness. PLoS One 2014; 9:e101165. [PMID: 24977417 PMCID: PMC4076312 DOI: 10.1371/journal.pone.0101165] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 06/03/2014] [Indexed: 12/22/2022] Open
Abstract
Hemispheric lateralization for language production and its relationships with manual preference and manual preference strength were studied in a sample of 297 subjects, including 153 left-handers (LH). A hemispheric functional lateralization index (HFLI) for language was derived from fMRI acquired during a covert sentence generation task as compared with a covert word list recitation. The multimodal HFLI distribution was optimally modeled using a mixture of 3 and 4 Gaussian functions in right-handers (RH) and LH, respectively. Gaussian function parameters helped to define 3 types of language hemispheric lateralization, namely "Typical" (left hemisphere dominance with clear positive HFLI values, 88% of RH, 78% of LH), "Ambilateral" (no dominant hemisphere with HFLI values close to 0, 12% of RH, 15% of LH) and "Strongly-atypical" (right-hemisphere dominance with clear negative HFLI values, 7% of LH). Concordance between dominant hemispheres for hand and for language did not exceed chance level, and most of the association between handedness and language lateralization was explained by the fact that all Strongly-atypical individuals were left-handed. Similarly, most of the relationship between language lateralization and manual preference strength was explained by the fact that Strongly-atypical individuals exhibited a strong preference for their left hand. These results indicate that concordance of hemispheric dominance for hand and for language occurs barely above the chance level, except in a group of rare individuals (less than 1% in the general population) who exhibit strong right hemisphere dominance for both language and their preferred hand. They call for a revisit of models hypothesizing common determinants for handedness and for language dominance.
Collapse
Affiliation(s)
- Bernard Mazoyer
- Groupe d’Imagerie Neurofonctionnelle, Centre National de la Recherche Scientifique, Commissariat à l’Energie Atomique, et Université de Bordeaux, Bordeaux, France
| | - Laure Zago
- Groupe d’Imagerie Neurofonctionnelle, Centre National de la Recherche Scientifique, Commissariat à l’Energie Atomique, et Université de Bordeaux, Bordeaux, France
| | - Gaël Jobard
- Groupe d’Imagerie Neurofonctionnelle, Centre National de la Recherche Scientifique, Commissariat à l’Energie Atomique, et Université de Bordeaux, Bordeaux, France
| | - Fabrice Crivello
- Groupe d’Imagerie Neurofonctionnelle, Centre National de la Recherche Scientifique, Commissariat à l’Energie Atomique, et Université de Bordeaux, Bordeaux, France
| | - Marc Joliot
- Groupe d’Imagerie Neurofonctionnelle, Centre National de la Recherche Scientifique, Commissariat à l’Energie Atomique, et Université de Bordeaux, Bordeaux, France
| | - Guy Perchey
- Groupe d’Imagerie Neurofonctionnelle, Centre National de la Recherche Scientifique, Commissariat à l’Energie Atomique, et Université de Bordeaux, Bordeaux, France
| | - Emmanuel Mellet
- Groupe d’Imagerie Neurofonctionnelle, Centre National de la Recherche Scientifique, Commissariat à l’Energie Atomique, et Université de Bordeaux, Bordeaux, France
| | - Laurent Petit
- Groupe d’Imagerie Neurofonctionnelle, Centre National de la Recherche Scientifique, Commissariat à l’Energie Atomique, et Université de Bordeaux, Bordeaux, France
| | - Nathalie Tzourio-Mazoyer
- Groupe d’Imagerie Neurofonctionnelle, Centre National de la Recherche Scientifique, Commissariat à l’Energie Atomique, et Université de Bordeaux, Bordeaux, France
| |
Collapse
|
19
|
Loring DW, Gaillard WD, Bookheimer SY, Meador KJ, Ojemann JG. Cortical cartography reveals political and physical maps. Epilepsia 2014; 55:633-637. [PMID: 24815217 PMCID: PMC4197796 DOI: 10.1111/epi.12553] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2014] [Indexed: 11/28/2022]
Abstract
Advances in functional imaging have provided noninvasive techniques to probe brain organization of multiple constructs including language and memory. Because of high overall rates of agreements with older techniques, including Wada testing and cortical stimulation mapping (CSM), some have proposed that those approaches should be largely abandoned because of their invasiveness, and replaced with noninvasive functional imaging methods. High overall agreement, however, is based largely on concordant language lateralization in series dominated by cases of typical cerebral dominance. Advocating a universal switch from Wada testing and cortical stimulation mapping to functional magnetic resonance imaging (fMRI) or magnetoencephalography (MEG) ignores the differences in specific expertise across epilepsy centers, many of which often have greater skill with one approach rather than the other, and that Wada, CSM, fMRI, and MEG protocols vary across institutions resulting in different outcomes and reliability. Specific patient characteristics also affect whether Wada or CSM might influence surgical management, making it difficult to accept broad recommendations against currently useful clinical tools. Although the development of noninvasive techniques has diminished the frequency of more invasive approaches, advocating their use to replace Wada testing and CSM across all epilepsy surgery programs without consideration of the different skills, protocols, and expertise at any given center site is ill-advised.
Collapse
Affiliation(s)
- David W. Loring
- Departments of Neurology and Pediatrics, Emory University, Atlanta, GA
| | | | | | - Kimford J. Meador
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA
| | | |
Collapse
|
20
|
Brown TT, Erhart M, Avesar D, Dale AM, Halgren E, Evans JL. Atypical right hemisphere specialization for object representations in an adolescent with specific language impairment. Front Hum Neurosci 2014; 8:82. [PMID: 24592231 PMCID: PMC3924145 DOI: 10.3389/fnhum.2014.00082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 02/03/2014] [Indexed: 11/24/2022] Open
Abstract
Individuals with a diagnosis of specific language impairment (SLI) show abnormal spoken language occurring alongside normal non-verbal abilities. Behaviorally, people with SLI exhibit diverse profiles of impairment involving phonological, grammatical, syntactic, and semantic aspects of language. In this study, we used a multimodal neuroimaging technique called anatomically constrained magnetoencephalography (aMEG) to measure the dynamic functional brain organization of an adolescent with SLI. Using single-subject statistical maps of cortical activity, we compared this patient to a sibling and to a cohort of typically developing subjects during the performance of tasks designed to evoke semantic representations of concrete objects. Localized patterns of brain activity within the language impaired patient showed marked differences from the typical functional organization, with significant engagement of right hemisphere heteromodal cortical regions generally homotopic to the left hemisphere areas that usually show the greatest activity for such tasks. Functional neuroanatomical differences were evident at early sensoriperceptual processing stages and continued through later cognitive stages, observed specifically at latencies typically associated with semantic encoding operations. Our findings show with real-time temporal specificity evidence for an atypical right hemisphere specialization for the representation of concrete entities, independent of verbal motor demands. More broadly, our results demonstrate the feasibility and potential utility of using aMEG to characterize individual patient differences in the dynamic functional organization of the brain.
Collapse
Affiliation(s)
- Timothy T Brown
- Multimodal Imaging Laboratory, University of California San Diego , La Jolla, CA , USA ; Department of Neurosciences, School of Medicine, University of California San Diego , La Jolla, CA , USA ; Center for Human Development, University of California San Diego , La Jolla, CA , USA
| | - Matthew Erhart
- Multimodal Imaging Laboratory, University of California San Diego , La Jolla, CA , USA ; Department of Radiology, School of Medicine, University of California San Diego , La Jolla, CA , USA
| | - Daniel Avesar
- Program in Experimental and Molecular Medicine, Dartmouth Medical School , Hanover, NH , USA
| | - Anders M Dale
- Multimodal Imaging Laboratory, University of California San Diego , La Jolla, CA , USA ; Department of Neurosciences, School of Medicine, University of California San Diego , La Jolla, CA , USA ; Department of Radiology, School of Medicine, University of California San Diego , La Jolla, CA , USA
| | - Eric Halgren
- Multimodal Imaging Laboratory, University of California San Diego , La Jolla, CA , USA ; Department of Neurosciences, School of Medicine, University of California San Diego , La Jolla, CA , USA ; Department of Radiology, School of Medicine, University of California San Diego , La Jolla, CA , USA
| | - Julia L Evans
- Center for Research in Language, University of California San Diego , La Jolla, CA , USA ; School of Behavioral and Brain Sciences, University of Texas Dallas , Dallas, TX , USA
| |
Collapse
|
21
|
Gamma activity modulated by picture and auditory naming tasks: intracranial recording in patients with focal epilepsy. Clin Neurophysiol 2013; 124:1737-44. [PMID: 23688918 DOI: 10.1016/j.clinph.2013.01.030] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 01/27/2013] [Accepted: 01/30/2013] [Indexed: 11/23/2022]
Abstract
OBJECTIVE We measured the spatial, temporal and developmental patterns of gamma activity augmented by picture- and auditory-naming tasks and determined the clinical significance of naming-related gamma-augmentation. METHODS We studied 56 epileptic patients (age: 4-56 years) who underwent extraoperative electrocorticography. The picture-naming task consisted of naming of a visually-presented object; the auditory-naming task consisted of answering an auditorily-presented sentence question. RESULTS Naming-related gamma-augmentation at 50-120 Hz involved the modality-specific sensory cortices during stimulus presentation and inferior-Rolandic regions during responses. Gamma-augmentation in the bilateral occipital and inferior/medial-temporal regions was more intense in the picture-naming than auditory-naming task, whereas that in the bilateral superior-temporal, left middle-temporal, left inferior-parietal, and left frontal regions was more intense in the auditory-naming task. Patients above 10 years old, compared to those younger, showed more extensive gamma-augmentation in the left dorsolateral-premotor region. Resection of sites showing naming-related gamma-augmentation in the left hemisphere assumed to contain essential language function was associated with increased risk of post-operative language deficits requiring speech therapy (p < 0.05). CONCLUSIONS Measurement of gamma-augmentation elicited by either naming task was useful to predict postoperative language deficits. SIGNIFICANCE A smaller degree of frontal engagement in the picture-naming task can be explained by no requirement of syntactic processing or less working memory load. More extensive gamma-augmentation in the left dorsolateral-premotor region in older individuals may suggest more proficient processing by the mature brain.
Collapse
|