Electrically induced verbal perseveration

Neurology ◽  
2019 ◽  
Vol 92 (6) ◽  
pp. e613-e621 ◽  
Author(s):  
Emmanuel Mandonnet ◽  
Guillaume Herbet ◽  
Sylvie Moritz-Gasser ◽  
Isabelle Poisson ◽  
François Rheault ◽  
...  
Keyword(s):  
White Matter ◽  
Cognitive Model ◽  
Neural Correlates ◽  
Tunable Filter ◽  
Montreal Neurological Institute ◽  
Glioma Surgery ◽  
Semantic System ◽  
Postoperative Mri ◽  
External Capsule ◽  
Temporal Horn

ObjectiveThe present study aimed to elucidate the neural correlates of the deafferentation cognitive model of verbal perseveration (VP) by analyzing the connectomics of the sites where electric stimulation elicited VP during awake left glioma surgery.MethodsWe retrospectively reviewed the anatomic sites that generated VP when electrically stimulated in a series of 21 patients operated on while awake for a left glioma. Each stimulation point was manually located on the postoperative MRI and then registered to the Montreal Neurological Institute template. Connectomics of these sites were further analyzed with Tractotron and disconnectome maps.ResultsVP stimulation sites were located within the white matter surrounding the posterosuperior head of the caudate nucleus, as well as within the white matter of the external capsule and the superolateral wall of the temporal horn of the ventricle. Furthermore, Tractotron and disconnectome maps revealed the connectome of these stimulation sites: the inferior fronto-occipital fasciculus, frontostriatal tract, and anterior thalamic radiations.ConclusionOn the basis of these results and other data, we propose the following anatomic implementation of the deafferentation cognitive model: the lexico-semantic system, comprising different areas linked together through direct cortico-cortical connections, sends information to the striatum; the striato-thalamic system acts as a tunable filter of this lexico-semantic input; and the thalamus projects back to the lexico-semantic system, amplifying the targeted response and inhibiting its competitors.

Cortical and Subcortical Anatomy of the Orbitofrontal Cortex: A White Matter Microfiberdissection Study and Case Series

2021 ◽  
Author(s):  
Philip Rauch ◽  
Carlo Serra ◽  
Luca Regli ◽  
Andreas Gruber ◽  
Martin Aichholzer ◽  
...  
Keyword(s):  
White Matter ◽  
Orbitofrontal Cortex ◽  
Case Series ◽  
Glioma Surgery ◽  
Lentiform Nucleus ◽  
External Capsule ◽  
Radiological Data ◽  
Frontal Horn ◽  
Secondary Objective ◽  
Glioma Resection

ABSTRACT BACKGROUND The literature on white matter anatomy underlying the human orbitofrontal cortex (OFC) is scarce in spite of its relevance for glioma surgery. OBJECTIVE To describe the anatomy of the OFC and of the underlying white matter fiber anatomy, with a particular focus on the surgical structures relevant for a safe and efficient orbitofrontal glioma resection. Based on anatomical and radiological data, the secondary objective was to describe the growth pattern of OFC gliomas. METHODS The study was performed on 10 brain specimens prepared according to Klingler's protocol and dissected using the fiber microdissection technique modified according to U.T., under the microscope at high magnification. RESULTS A detailed stratigraphy of the OFC was performed, from the cortex up to the frontal horn of the lateral ventricle. The interposed neural structures are described together with relevant neighboring topographic areas and nuclei. Combining anatomical and radiological data, it appears that the anatomical boundaries delimiting and guiding the macroscopical growth of OFC gliomas are as follows: the corpus callosum superiorly, the external capsule laterally, the basal forebrain and lentiform nucleus posteriorly, and the gyrus rectus medially. Thus, OFC gliomas seem to grow ventriculopetally, avoiding the laterally located neocortex. CONCLUSION The findings in our study supplement available anatomical knowledge of the OFC, providing reliable landmarks for a precise topographical diagnosis of OFC lesions and for perioperative orientation. The relationships between deep anatomic structures and glioma formations described in this study are relevant for surgery in this highly interconnected area.

What Has Direct Cortical and Subcortical Electrostimulation Taught Us about Neurolinguistics?

2019 ◽  
pp. 185-211
Author(s):  
Hugues Duffau
Keyword(s):  
White Matter ◽  
Large Scale ◽  
Functional Neuroimaging ◽  
Great Accuracy ◽  
Subcortical White Matter ◽  
Cerebral Lesions ◽  
Physiological Basis ◽  
Postoperative Mri ◽  
The Brain

Investigating the neural and physiological basis of language is one of the most important challenges in neurosciences. Direct electrical stimulation (DES), usually performed in awake patients during surgery for cerebral lesions, is a reliable tool for detecting both cortical and subcortical (white matter and deep grey nuclei) regions crucial for cognitive functions, especially language. DES transiently interacts locally with a small cortical or axonal site, but also nonlocally, as the focal perturbation will disrupt the entire subnetwork sustaining a given function. Thus, in contrast to functional neuroimaging, DES represents a unique opportunity to identify with great accuracy and reproducibility, in vivo in humans, the structures that are actually indispensable to the function, by inducing a transient virtual lesion based on the inhibition of a subcircuit lasting a few seconds. Currently, this is the sole technique that is able to directly investigate the functional role of white matter tracts in humans. Thus, combining transient disturbances elicited by DES with the anatomical data provided by pre- and postoperative MRI enables to achieve reliable anatomo-functional correlations, supporting a network organization of the brain, and leading to the reappraisal of models of language representation. Finally, combining serial peri-operative functional neuroimaging and online intraoperative DES allows the study of mechanisms underlying neuroplasticity. This chapter critically reviews the basic principles of DES, its advantages and limitations, and what DES can reveal about the neural foundations of language, that is, the large-scale distribution of language areas in the brain, their connectivity, and their ability to reorganize.

scholarly journals Failure of diffusion-weighted imaging in intraoperative 3 Tesla MRI to identify hyperacute strokes during glioma surgery

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stefanos Voglis ◽  
Aimee Hiller ◽  
Anna-Sophie Hofer ◽  
Lazar Tosic ◽  
Oliver Bozinov ◽  
...  
Keyword(s):  
Diffusion Weighted Imaging ◽  
Brain Injuries ◽  
Infarct Volume ◽  
False Negative ◽  
Size Estimation ◽  
Glioma Surgery ◽  
Postoperative Mri ◽  
Diffusion Weighted ◽  
Tumor Types ◽  
Additional Resection

AbstractIntraoperatively acquired diffusion-weighted imaging (DWI) sequences in cranial tumor surgery are used for early detection of ischemic brain injuries, which could result in impaired neurological outcome and their presence might thus influence the neurosurgeon’s decision on further resection. The phenomenon of false-negative DWI findings in intraoperative magnetic resonance imaging (ioMRI) has only been reported in single cases and therefore yet needs to be further analyzed. This retrospective single-center study’s objective was the identification and characterization of false-negative DWI findings in ioMRI with new or enlarged ischemic areas on postoperative MRI (poMRI). Out of 225 cranial tumor surgeries with intraoperative DWI sequences, 16 cases with no additional resection after ioMRI and available in-time poMRI (< 14 days) were identified. Of these, a total of 12 cases showed false-negative DWI in ioMRI (75%). The most frequent tumor types were oligodendrogliomas and glioblastomas (4 each). In 5/12 cases (41.7%), an ischemic area was already present in ioMRI, however, volumetrically increased in poMRI (mean infarct growth + 2.1 cm3; 0.48–3.6), whereas 7 cases (58.3%) harbored totally new infarcts on poMRI (mean infarct volume 0.77 cm3; 0.05–1.93). With this study we provide the most comprehensive series of false-negative DWI findings in ioMRI that were not followed by additional resection. Our study underlines the limitations of intraoperative DWI sequences for the detection and size-estimation of hyperacute infarction. The awareness of this phenomenon is crucial for any neurosurgeon utilizing ioMRI.

Diffusion tensor tractography of the temporal stem on the inferior limiting sulcus

2008 ◽  
Vol 108 (4) ◽  
pp. 775-781 ◽  
Author(s):  
Feng Wang ◽  
Tao Sun ◽  
Xing-Gang Li ◽  
Na-Jia Liu
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Anterior Commissure ◽  
Region Of Interest ◽  
Diffusion Tensor Tractography ◽  
Optic Radiation ◽  
Uncinate Fasciculus ◽  
White Matter Tracts ◽  
Temporal Horn ◽  
Temporal Stem

Object The aim of this study was to use diffusion tensor tractography (DTT) to define the 3D relationships of the uncinate fasciculus, anterior commissure, inferior occipitofrontal fasciculus, inferior thalamic peduncle, and optic radiation and to determine the positioning landmarks of these white matter tracts. Methods The anatomy was studied in 10 adult human brain specimens. Brain DTT was performed in 10 healthy volunteers. Diffusion tensor tractography images of the white matter tracts in the temporal stem were obtained using the simple single region of interest (ROI) and multi-ROIs based on the anatomical knowledge. Results The posteroinferior insular point is the anterior extremity of intersection of the Heschl gyrus and the inferior limiting sulcus. On the inferior limiting sulcus, this point is the posterior limit of the optic radiation, and the temporal stem begins at the limen insulae and ends at the posteroinferior insular point. The distance from the limen insulae to the tip of the temporal horn is just one third the length of the temporal stem. The uncinate fasciculus comprises the core of the anterior temporal stem, behind which the anterior commissure and the inferior thalamic peduncle are located, and they occupy the anterior third of the temporal stem. The inferior occipitofrontal fasciculus passes through the entire temporal stem. The most anterior extent of the Meyer loop is located between the anterior tip of the temporal horn and the limen insulae. Most of the optic radiation crosses the postmedian two thirds of the temporal stem. Conclusions On the inferior limiting sulcus, the posteroinferior insular point is a reliable landmark of the posterior limit of the optic radiations. The limen insulae, anterior tip of the temporal horn, and posteroinferior insular point may be used to localize the white matter fibers of the temporal stem in analyzing magnetic resonance imaging or during surgery.

scholarly journals High-definition fiber tractography for the evaluation of perilesional white matter tracts in high-grade glioma surgery

2015 ◽  
pp. nov113 ◽  
Author(s):  
Kumar Abhinav ◽  
Fang-Cheng Yeh ◽  
Alireza Mansouri ◽  
Gelareh Zadeh ◽  
Juan C. Fernandez-Miranda
Keyword(s):  
White Matter ◽  
High Grade Glioma ◽  
High Grade ◽  
Fiber Tractography ◽  
High Definition ◽  
Glioma Surgery ◽  
White Matter Tracts

scholarly journals Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) presenting with stroke in a young man

2019 ◽  
Vol 12 (7) ◽  
pp. e229609
Author(s):  
Louise Dunphy ◽  
Amir Rani ◽  
Yaw Duodu ◽  
Yousef Behnam
Keyword(s):  
White Matter ◽  
Autosomal Dominant ◽  
Age Of Onset ◽  
Cerebral Atrophy ◽  
Microvascular Disease ◽  
Lower Limbs ◽  
Receptor Protein ◽  
External Capsule ◽  
Ct Head ◽  
Epidermal Growth

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is caused by mutations in the NOTCH3 gene which maps to the short arm of chromosome 19 and encodes the NOTCH3 receptor protein, predominantly expressed in adults by vascular smooth muscle cells and pericytes. The receptor has a large extracellular domain with 34 epidermal growth factor-like repeats encoded by exons 2–24, the site at which CADASIL mutations are most commonly found. Migraine with aura is often the earliest feature of the disease, with an increased susceptibility to cortical spreading depression suggested as a possible aetiological mechanism. Stroke, acute encephalopathy and cognitive impairment can also occur. Hypertension and smoking are associated with early age of onset of stroke. It diffusely affects white matter, with distinct findings on T2- weighted MRI, involving the external capsule, anterior poles of the temporal lobe and superior frontal gyri, displaying a characteristic pattern of leucoencephalopathy. Affected individuals have a reduced life expectancy. An effective treatment for CADASIL is not available. The authors describe a 35-year-old manwith an unremarkable medical history, presenting to the emergency department with slurred speech and increased confusion 3 days following a fall. He was a smoker and consumed 16 units of alcohol weekly. He was hypertensive and tachycardic. Physical examination confirmed increased tone in his lower limbs and dysarthria. His CT head showed severe cerebral atrophy, multiple small old infarcts and moderate background microvascular disease. Further investigation with an MRI head confirmed multiple white matter abnormalities with microhaemorrhages. The possibility of a hereditary vasculopathy was rendered as the appearances were thought consistent with a diagnosis of CADASIL. Genetic testing identified the NOTCH3 gene thus confirming the diagnosis. This paper provides an overview of the aetiology, clinical presentation, pathogenesis, investigations and management of CADASIL.

scholarly journals A unified model of post-stroke language deficits including discourse production and their neural correlates

Brain ◽  
2020 ◽  
Vol 143 (5) ◽  
pp. 1541-1554 ◽  
Author(s):  
Reem S W Alyahya ◽  
Ajay D Halai ◽  
Paul Conroy ◽  
Matthew A Lambon Ralph
Keyword(s):  
Principal Component Analysis ◽  
White Matter ◽  
Speech Production ◽  
Principal Component ◽  
Neural Correlates ◽  
Unified Model ◽  
Connected Speech ◽  
Lexical Diversity ◽  
Post Stroke ◽  
Procedural Discourse

Abstract The clinical profiles of individuals with post-stroke aphasia demonstrate considerable variation in the presentation of symptoms. Recent aphasiological studies have attempted to account for this individual variability using a multivariate data-driven approach (principal component analysis) on an extensive neuropsychological and aphasiological battery, to identify fundamental domains of post-stroke aphasia. These domains mainly reflect phonology, semantics and fluency; however, these studies did not account for variability in response to different forms of connected speech, i.e. discourse genres. In the current study, we initially examined differences in the quantity, diversity and informativeness between three different discourse genres, including a simple descriptive genre and two naturalistic forms of connected speech (storytelling narrative, and procedural discourse). Subsequently, we provided the first quantitative investigation on the multidimensionality of connected speech production at both behavioural and neural levels. Connected speech samples across descriptive, narrative, and procedural discourse genres were collected from 46 patients with chronic post-stroke aphasia and 20 neurotypical adults. Content analyses conducted on all connected speech samples indicated that performance differed across discourse genres and between groups. Specifically, storytelling narratives provided higher quantities of content words and lexical diversity compared to composite picture description and procedural discourse. The analyses further revealed that, relative to neurotypical adults, patients with aphasia, both fluent and non-fluent, showed reduction in the quantity of verbal production, lexical diversity, and informativeness across all discourses. Given the differences across the discourses, we submitted the connected speech metrics to principal component analysis alongside an extensive neuropsychological/aphasiological battery that assesses a wide range of language and cognitive skills. In contrast to previous research, three unique orthogonal connected speech components were extracted in a unified model, reflecting verbal quantity, verbal quality, and motor speech, alongside four core language and cognitive components: phonological production, semantic processing, phonological recognition, and executive functions. Voxel-wise lesion-symptom mapping using these components provided evidence on the involvement of widespread cortical regions and their white matter connections. Specifically, left frontal regions and their underlying white matter tracts corresponding to the frontal aslant tract and the anterior segment of the arcuate fasciculus were particularly engaged with the quantity and quality of fluent connected speech production while controlling for other co-factors. The neural correlates associated with the other language domains align with existing models on the ventral and dorsal pathways for language processing.

scholarly journals Intraoperative perception and estimates on extent of resection during awake glioma surgery: overcoming the learning curve

2018 ◽  
Vol 128 (5) ◽  
pp. 1410-1418 ◽  
Author(s):  
Darryl Lau ◽  
Shawn L. Hervey-Jumper ◽  
Seunggu J. Han ◽  
Mitchel S. Berger
Keyword(s):  
Learning Curve ◽  
Tumor Resection ◽  
Extent Of Resection ◽  
Neurological Deficits ◽  
Language Outcomes ◽  
Glioma Surgery ◽  
Ample Evidence ◽  
Postoperative Mri ◽  
Significant Difference ◽  
Surgeon Experience

OBJECTIVEThere is ample evidence that extent of resection (EOR) is associated with improved outcomes for glioma surgery. However, it is often difficult to accurately estimate EOR intraoperatively, and surgeon accuracy has yet to be reviewed. In this study, the authors quantitatively assessed the accuracy of intraoperative perception of EOR during awake craniotomy for tumor resection.METHODSA single-surgeon experience of performing awake craniotomies for tumor resection over a 17-year period was examined. Retrospective review of operative reports for quantitative estimation of EOR was recorded. Definitive EOR was based on postoperative MRI. Analysis of accuracy of EOR estimation was examined both as a general outcome (gross-total resection [GTR] or subtotal resection [STR]), and quantitatively (5% within EOR on postoperative MRI). Patient demographics, tumor characteristics, and surgeon experience were examined. The effects of accuracy on motor and language outcomes were assessed.RESULTSA total of 451 patients were included in the study. Overall accuracy of intraoperative perception of whether GTR or STR was achieved was 79.6%, and overall accuracy of quantitative perception of resection (within 5% of postoperative MRI) was 81.4%. There was a significant difference (p = 0.049) in accuracy for gross perception over the 17-year period, with improvement over the later years: 1997–2000 (72.6%), 2001–2004 (78.5%), 2005–2008 (80.7%), and 2009–2013 (84.4%). Similarly, there was a significant improvement (p = 0.015) in accuracy of quantitative perception of EOR over the 17-year period: 1997–2000 (72.2%), 2001–2004 (69.8%), 2005–2008 (84.8%), and 2009–2013 (93.4%). This improvement in accuracy is demonstrated by the significantly higher odds of correctly estimating quantitative EOR in the later years of the series on multivariate logistic regression. Insular tumors were associated with the highest accuracy of gross perception (89.3%; p = 0.034), but lowest accuracy of quantitative perception (61.1% correct; p < 0.001) compared with tumors in other locations. Even after adjusting for surgeon experience, this particular trend for insular tumors remained true. The absence of 1p19q co-deletion was associated with higher quantitative perception accuracy (96.9% vs 81.5%; p = 0.051). Tumor grade, recurrence, diagnosis, and isocitrate dehydrogenase-1 (IDH-1) status were not associated with accurate perception of EOR. Overall, new neurological deficits occurred in 8.4% of cases, and 42.1% of those new neurological deficits persisted after the 3-month follow-up. Correct quantitative perception was associated with lower postoperative motor deficits (2.4%) compared with incorrect perceptions (8.0%; p = 0.029). There were no detectable differences in language outcomes based on perception of EOR.CONCLUSIONSThe findings from this study suggest that there is a learning curve associated with the ability to accurately assess intraoperative EOR during glioma surgery, and it may take more than a decade to be truly proficient. Understanding the factors associated with this ability to accurately assess EOR will provide safer surgeries while maximizing tumor resection.

scholarly journals Microsurgical anatomy of the central core of the brain

2018 ◽  
Vol 129 (3) ◽  
pp. 752-769 ◽  
Author(s):  
Eduardo Carvalhal Ribas ◽  
Kaan Yağmurlu ◽  
Evandro de Oliveira ◽  
Guilherme Carvalhal Ribas ◽  
Albert Rhoton
Keyword(s):  
White Matter ◽  
Caudate Nucleus ◽  
Internal Capsule ◽  
Central Core ◽  
Surgical Approaches ◽  
Microsurgical Anatomy ◽  
Functional Importance ◽  
Posterior Portion ◽  
External Capsule ◽  
The Brain

OBJECTIVEThe purpose of this study was to describe in detail the cortical and subcortical anatomy of the central core of the brain, defining its limits, with particular attention to the topography and relationships of the thalamus, basal ganglia, and related white matter pathways and vessels.METHODSThe authors studied 19 cerebral hemispheres. The vascular systems of all of the specimens were injected with colored silicone, and the specimens were then frozen for at least 1 month to facilitate identification of individual fiber tracts. The dissections were performed in a stepwise manner, locating each gray matter nucleus and white matter pathway at different depths inside the central core. The course of fiber pathways was also noted in relation to the insular limiting sulci.RESULTSThe insular surface is the most superficial aspect of the central core and is divided by a central sulcus into an anterior portion, usually containing 3 short gyri, and a posterior portion, with 2 long gyri. It is bounded by the anterior limiting sulcus, the superior limiting sulcus, and the inferior limiting sulcus. The extreme capsule is directly underneath the insular surface and is composed of short association fibers that extend toward all the opercula. The claustrum lies deep to the extreme capsule, and the external capsule is found medial to it. Three fiber pathways contribute to form both the extreme and external capsules, and they lie in a sequential anteroposterior disposition: the uncinate fascicle, the inferior fronto-occipital fascicle, and claustrocortical fibers. The putamen and the globus pallidus are between the external capsule, laterally, and the internal capsule, medially. The internal capsule is present medial to almost all insular limiting sulci and most of the insular surface, but not to their most anteroinferior portions. This anteroinferior portion of the central core has a more complex anatomy and is distinguished in this paper as the “anterior perforated substance region.” The caudate nucleus and thalamus lie medial to the internal capsule, as the most medial structures of the central core. While the anterior half of the central core is related to the head of the caudate nucleus, the posterior half is related to the thalamus, and hence to each associated portion of the internal capsule between these structures and the insular surface. The central core stands on top of the brainstem. The brainstem and central core are connected by several white matter pathways and are not separated from each other by any natural division. The authors propose a subdivision of the central core into quadrants and describe each in detail. The functional importance of each structure is highlighted, and surgical approaches are suggested for each quadrant of the central core.CONCLUSIONSAs a general rule, the internal capsule and its vascularization should be seen as a parasagittal barrier with great functional importance. This is of particular importance in choosing surgical approaches within this region.

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