scholarly journals The Frontal Aslant Tract: A Systematic Review for Neurosurgical Applications

2021 ◽  
Vol 12 ◽  
Author(s):  
Emanuele La Corte ◽  
Daniela Eldahaby ◽  
Elena Greco ◽  
Domenico Aquino ◽  
Giacomo Bertolini ◽  
...  
Keyword(s):  
Systematic Review ◽  
White Matter ◽  
Inferior Frontal Gyrus ◽  
Primary Progressive Aphasia ◽  
Autism Spectrum ◽  
Sentence Production ◽  
Microstructural Alterations ◽  
Language Functions ◽  
Brain White Matter ◽  
Frontal Aslant Tract

The frontal aslant tract (FAT) is a recently identified white matter tract connecting the supplementary motor complex and lateral superior frontal gyrus to the inferior frontal gyrus. Advancements in neuroimaging and refinements to anatomical dissection techniques of the human brain white matter contributed to the recent description of the FAT anatomical and functional connectivity and its role in the pathogenesis of several neurological, psychiatric, and neurosurgical disorders. Through the application of diffusion tractography and intraoperative electrical brain stimulation, the FAT was shown to have a role in speech and language functions (verbal fluency, initiation and inhibition of speech, sentence production, and lexical decision), working memory, visual–motor activities, orofacial movements, social community tasks, attention, and music processing. Microstructural alterations of the FAT have also been associated with neurological disorders, such as primary progressive aphasia, post-stroke aphasia, stuttering, Foix–Chavany–Marie syndrome, social communication deficit in autism spectrum disorders, and attention–deficit hyperactivity disorder. We provide a systematic review of the current literature about the FAT anatomical connectivity and functional roles. Specifically, the aim of the present study relies on providing an overview for practical neurosurgical applications for the pre-operative, intra-operative, and post-operative assessment of patients with brain tumors located around and within the FAT. Moreover, some useful tests are suggested for the neurosurgical evaluation of FAT integrity to plan a safer surgery and to reduce post-operative deficits.

scholarly journals Paternal age contribution to brain white matter aberrations in autism spectrum disorder

2019 ◽  
Vol 73 (10) ◽  
pp. 649-659 ◽  
Author(s):  
Walid Yassin ◽  
Masaki Kojima ◽  
Keiho Owada ◽  
Hitoshi Kuwabara ◽  
Wataru Gonoi ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
White Matter ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Paternal Age ◽  
Brain White Matter

scholarly journals Whole-brain white matter disruption in semantic and nonfluent variants of primary progressive aphasia

2011 ◽  
Vol 34 (4) ◽  
pp. 973-984 ◽  
Author(s):  
Graeme C. Schwindt ◽  
Naida L. Graham ◽  
Elizabeth Rochon ◽  
David F. Tang-Wai ◽  
Nancy J. Lobaugh ◽  
...  
Keyword(s):  
White Matter ◽  
Primary Progressive Aphasia ◽  
Whole Brain ◽  
Progressive Aphasia ◽  
Primary Progressive ◽  
Brain White Matter

scholarly journals Reduced Brain Volume and White Matter Alterations in Shank3-Deficient Rats

2020 ◽  
Author(s):  
Carla Esther Meyer Golden ◽  
Victoria X Wang ◽  
Hala Harony-Nicolas ◽  
Patrick R. Hof ◽  
Joseph Buxbaum
Keyword(s):  
White Matter ◽  
Brain Structure ◽  
Brain Volume ◽  
Diffusion Tensor ◽  
Brain Size ◽  
Brain Regions ◽  
Autism Spectrum ◽  
Wild Type ◽  
Microstructural Alterations ◽  
The Brain

Abstract Background: Mutations and deletions in the SHANK3 synaptic gene cause the major neurodevelopmental features of Phelan-McDermid syndrome (PMS). The SHANK3 gene encodes a key structural component of excitatory synapses that is important for synaptogenesis. PMS is characterized by intellectual disability, autism spectrum disorder, cognitive deficits, physical dysmorphic features, sensory hyporeactivity, and alterations in the size of multiple brain regions. Clinical assessments and limited imaging studies have revealed a reduction in volume of multiple brain regions. They have also found white matter thinning and microstructural alterations to be persistent in patients with PMS. While many of these impairments have been replicated in mouse models of PMS, the brain structure of a rat model has not yet been studied. Methods: We assessed the brain structure of haploinsufficient and homozygous Shank3-deficient rats that model the behavioral deficits of PMS with magnetic resonance and diffusion tensor imaging, and compared their brain structure to wild type littermates.Results: Both gray and white matter structures were smaller in Shank3-deficient rats, leading to an overall reduction in brain size compared to wild type littermates. The largest region to be diminished in size was the neocortex. Some regions involved in sensory processing and white matter regions were also reduced in size. Lastly, the microstructure of two white matter tracts, the external capsule and fornix, was abnormal.Conclusions: Shank3-deficient rats replicate the reduced brain volume and altered white matter phenotypes present in individuals with PMS. Therefore, the brain regions that were altered represent potential cross-species structural biomarkers that warrant further study.

OS10.7.A Localization patterns of language errors during direct electrical brain stimulation: a systematic review

2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii14-ii14
Author(s):  
E Collée ◽  
A Vincent ◽  
C Dirven ◽  
D Satoer
Keyword(s):  
Systematic Review ◽  
Inferior Frontal Gyrus ◽  
Superior Temporal Gyrus ◽  
Standard Addition ◽  
Wide Distribution ◽  
Awake Craniotomy ◽  
Cortical Mapping ◽  
Precentral Gyrus ◽  
Language Functions ◽  
Language Outcome

Abstract BACKGROUND Awake craniotomy with direct electrical stimulation (DES) is the standard treatment for patients with eloquent area gliomas. Language errors (paraphasias) are detected with DES and they indicate functional boundaries that need to be maintained to preserve quality of life. However, it is not fully clear in which brain locations paraphasias at different linguistic modalities and levels (production, comprehension, reading, writing, phonology, semantics, syntax) occur. MATERIALS AND METHODS A systematic review was conducted. We included 102 studies reporting on specific paraphasias and the corresponding brain locations during awake craniotomy with DES in adult glioma patients. RESULTS First, a wide distribution of brain locations for all paraphasias (n=930) was found, but patterns were observed. Cortically, paraphasias occurred most often in the precentral gyrus (22%), while subcortically, they occurred mainly at the inferior fronto-occipital fascicle (IFOF: 10%). Localization patterns for different paraphasia types and the corresponding language functions were also found: production/articulation (n=393)-precentral gyrus (41%), inferior frontal gyrus (9%), frontal aslant/striatal tract (4%), postcentral gyrus (3%); semantics (n=128)-IFOF (57%), superior temporal gyrus (9%); phonology (n=115)-arcuate fascicle (52%), superior longitudinal fascicle (10%), uncinate fascicle (3%); reading (n=25)-temporal lobe (48%), inferior longitudinal fascicle (32%); syntax (n=15)-inferior frontal gyrus (27%); speech initiation (n=9)-supplementary motor area (33%), frontal aslant tract (22%), frontal striatal tract (22%); writing (n=7)-superior parietal gyrus (71%). Second, 59% of all paraphasias occurred cortically, 40% subcortically and 1% at both levels. CONCLUSION The localization of most paraphasias are consistent with the assumed functionality of those brain locations as presented in the Dutch Linguistic Intraoperative Protocol model. However, new locations for production/articulation, phonology, reading and writing were found. This needs to be taken into consideration for future selection of pre, intra and postoperative language tasks at different language modalities and levels. Additionally, DES should always be applied at the subcortical level as a standard addition to the routine cortical mapping during awake craniotomy. In conclusion, this is the first systematic review on the localization of specific paraphasias during awake craniotomy. Based on the identified language localization patterns, language tasks could be selected more accurately. This could guide, and perhaps improve, pre, intra and postoperative language testing and monitoring, which in turn, may pave the way to a better postoperative language outcome. The possible relation between different intraoperative paraphasias and language outcome has yet to be determined.

scholarly journals White Matter Integrity Predicts Electrical Stimulation (tDCS) and Language Therapy Effects in Primary Progressive Aphasia

2020 ◽  
Vol 35 (1) ◽  
pp. 44-57
Author(s):  
Yi Zhao ◽  
Bronte Ficek ◽  
Kimberly Webster ◽  
Constantine Frangakis ◽  
Brian Caffo ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Inferior Frontal Gyrus ◽  
Mean Diffusivity ◽  
Primary Progressive Aphasia ◽  
White Matter Integrity ◽  
Language Therapy ◽  
Progressive Aphasia ◽  
Primary Progressive ◽  
Language Pathways

Background Transcranial direct current stimulation (tDCS), in conjunction with language therapy, improves language therapy outcomes in primary progressive aphasia (PPA). However, no studies show whether white matter integrity predicts language therapy or tDCS effects in PPA. Objective We aimed to determine whether white matter integrity, measured by diffusion tensor imaging (DTI), predicts written naming/spelling language therapy effects (letter accuracy on trained and untrained words) with and without tDCS over the left inferior frontal gyrus (IFG) in PPA. Methods Thirty-nine participants with PPA were randomly assigned to tDCS or sham condition, coupled with language therapy for 15 daily sessions. White matter integrity was measured by mean diffusivity (MD) and fractional anisotropy (FA) in DTI scans before therapy. Written naming outcomes were evaluated before, immediately after, 2 weeks, and 2 months posttherapy. To assess tDCS treatment effect, we used a mixed-effects model with treatment evaluation and time interaction. We considered a forward model selection approach to identify brain regions/fasciculi of which white matter integrity can predict improvement in performance of word naming. Results Both sham and tDCS groups significantly improved in trained items immediately after and at 2 months posttherapy. Improvement in the tDCS group was greater and generalized to untrained words. White matter integrity of ventral language pathways predicted tDCS effects in trained items whereas white matter integrity of dorsal language pathways predicted tDCS effects in untrained items. Conclusions White matter integrity influences both language therapy and tDCS effects. Thus, it holds promise as a biomarker for deciding which patients will benefit from language therapy and tDCS.

scholarly journals White matter microstructural alterations across four major psychiatric disorders: mega-analysis study in 2937 individuals

2019 ◽  
Vol 25 (4) ◽  
pp. 883-895 ◽  
Author(s):  
Daisuke Koshiyama ◽  
◽  
Masaki Fukunaga ◽  
Naohiro Okada ◽  
Kentaro Morita ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Bipolar Disorder ◽  
Major Depressive Disorder ◽  
White Matter ◽  
Depressive Disorder ◽  
Psychiatric Disorders ◽  
Limbic System ◽  
Autism Spectrum ◽  
Major Depressive ◽  
Microstructural Alterations

AbstractIdentifying both the commonalities and differences in brain structures among psychiatric disorders is important for understanding the pathophysiology. Recently, the ENIGMA-Schizophrenia DTI Working Group performed a large-scale meta-analysis and reported widespread white matter microstructural alterations in schizophrenia; however, no similar cross-disorder study has been carried out to date. Here, we conducted mega-analyses comparing white matter microstructural differences between healthy comparison subjects (HCS; N = 1506) and patients with schizophrenia (N = 696), bipolar disorder (N = 211), autism spectrum disorder (N = 126), or major depressive disorder (N = 398; total N = 2937 from 12 sites). In comparison with HCS, we found that schizophrenia, bipolar disorder, and autism spectrum disorder share similar white matter microstructural differences in the body of the corpus callosum; schizophrenia and bipolar disorder featured comparable changes in the limbic system, such as the fornix and cingulum. By comparison, alterations in tracts connecting neocortical areas, such as the uncinate fasciculus, were observed only in schizophrenia. No significant difference was found in major depressive disorder. In a direct comparison between schizophrenia and bipolar disorder, there were no significant differences. Significant differences between schizophrenia/bipolar disorder and major depressive disorder were found in the limbic system, which were similar to the differences in schizophrenia and bipolar disorder relative to HCS. While schizophrenia and bipolar disorder may have similar pathological characteristics, the biological characteristics of major depressive disorder may be close to those of HCS. Our findings provide insights into nosology and encourage further investigations of shared and unique pathophysiology of psychiatric disorders.

scholarly journals The Role of the Right Hemisphere White Matter Tracts in Chronic Aphasic Patients After Damage of the Language Tracts in the Left Hemisphere

2021 ◽  
Vol 15 ◽  
Author(s):  
Evie Kourtidou ◽  
Dimitrios Kasselimis ◽  
Georgia Angelopoulou ◽  
Efstratios Karavasilis ◽  
Georgios Velonakis ◽  
...  
Keyword(s):  
White Matter ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Inferior Frontal Gyrus ◽  
Language Performance ◽  
White Matter Tracts ◽  
Post Stroke ◽  
Language Functions ◽  
The Right

The involvement of the right hemisphere (RH) in language, and especially after aphasia resulting from left hemisphere (LH) lesions, has been recently highlighted. The present study investigates white matter structure in the right hemisphere of 25 chronic post-stroke aphasic patients after LH lesions in comparison with 24 healthy controls, focusing on the four cortico-cortical tracts that link posterior parietal and temporal language-related areas with Broca’s region in the inferior frontal gyrus of the LH: the Superior Longitudinal Fasciculi II and III (SLF II and SLF III), the Arcuate Fasciculus (AF), and the Temporo-Frontal extreme capsule Fasciculus (TFexcF). Additionally, the relationship of these RH white matter tracts to language performance was examined. The patients with post-stroke aphasia in the chronic phase and the healthy control participants underwent diffusion tensor imaging (DTI) examination. The aphasic patients were assessed with standard aphasia tests. The results demonstrated increased axial diffusivity in the RH tracts of the aphasic patients. Patients were then divided according to the extent of the left hemisphere white matter loss. Correlations of language performance with radial diffusivity (RD) in the right hemisphere homologs of the tracts examined were demonstrated for the TFexcF, SLF III, and AF in the subgroup with limited damage to the LH language networks and only with the TFexcF in the subgroup with extensive damage. The results argue in favor of compensatory roles of the right hemisphere tracts in language functions when the LH networks are disrupted.

scholarly journals Examining the boundary sharpness coefficient as an index of cortical microstructure and its relationship to age and sex in autism spectrum disorder

2020 ◽  
Author(s):  
Emily Olafson ◽  
Saashi Bedford ◽  
Gabriel A. Devenyi ◽  
Raihaan Patel ◽  
Stephanie Tullo ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
White Matter ◽  
Cortical Thickness ◽  
Meta Analysis ◽  
Inferior Frontal Gyrus ◽  
Superior Temporal Gyrus ◽  
Brain Regions ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Sharpness Coefficient

AbstractAutism spectrum disorder (ASD) is associated with atypical brain development. However, the phenotype of regionally specific increased cortical thickness observed in ASD may be driven by several independent biological processes that influence the gray/white matter boundary, such as synaptic pruning, myelination, or atypical migration. Here, we propose to use the boundary sharpness coefficient (BSC), a proxy for alterations in microstructure at the cortical gray/white matter boundary, to investigate brain differences in individuals with ASD, including factors that may influence ASD-related heterogeneity (age, sex, and intelligence quotient). Using a vertex-based meta-analysis and a large multi-center magnetic resonance structural imaging (MRI) dataset, with a total of 1136 individuals, 415 with ASD (112 female; 303 male) and 721 controls (283 female; 438 male), we observed that individuals with ASD had significantly greater BSC in the bilateral superior temporal gyrus and left inferior frontal gyrus indicating an abrupt transition (high contrast) between white matter and cortical intensities. Increases were observed in different brain regions in males and females, with larger effect sizes in females. Individuals with ASD under 18 had significantly greater BSC in the bilateral superior temporal gyrus and right postcentral gyrus; individuals with ASD over 18 had significantly increased BSC in the bilateral precuneus and superior temporal gyrus. BSC correlated with ADOS-2 CSS in individuals with ASD in the right medial temporal pole. Importantly, there was a significant spatial overlap between maps of the effect of diagnosis on BSC when compared to cortical thickness. These results invite studies to use BSC as a possible new measure of cortical development in ASD and to further examine the microstructural underpinnings of BSC-related differences and their impact on measures of cortical morphology.

Sign in / Sign up

Export Citation Format

Share Document