A Connectomic Atlas of the Human Cerebrum—Chapter 14: Tractographic Description of the Frontal Aslant Tract

Briggs, Robert G.; Conner, Andrew K.; Rahimi, Meherzad; Sali, Goksel; Baker, Cordell M; Burks, Joshua D.; Glenn, Chad A.; Battiste, James; Sughrue, Michael E.

doi:10.1093/ons/opy268

Cited by 22 publications

(21 citation statements)

References 29 publications

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“…The FAT is a white matter fiber tract traveling in the coronal plane connecting the SFG to the ipsilateral IFG ( 27 ) ( Figure 2 ). According to the parcellation scheme developed by the Human Connectome Project (HCP), the FAT connects the SFG, in particular, two parcellations of the SMA complex (6ma and SFL) and two of the dorsolateral prefrontal cortex (8BL and S6-8) to the IFG (parcellations 44, 6r) and the frontal operculum (parcellations FOP1, FOP3, and FOP4) as well as the middle insula (MI) parcellation in the anterior insula ( 28 , 29 ). In line with the parcellation scheme, the tractography of the FAT shows terminations into the SFG, including not only the pre-SMA and SMA but also the lateral SFG ( 30 ).…”

Section: Discussionmentioning

confidence: 99%

“…The MI area lies in the posterior superior part of the short insular gyrus ( 39 ). The Human Connectome Project divided the insula in numerous parcellations ( 39 ) and found connections of the MI area with three SFG parcellations (6ma, 8BL, and SFL) through the FAT ( 29 ). The termination of the FAT in the insula has not been extensively studied, but Baker et al ( 39 ) noted that a previously known network, the salience network (SN), has as nodes both FAT terminations and the anterior insula.…”

Section: Discussionmentioning

confidence: 99%

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The Frontal Aslant Tract: A Systematic Review for Neurosurgical Applications

et al. 2021

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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.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The Frontal Aslant Tract: A Systematic Review for Neurosurgical Applications

et al. 2021

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“…The frontal aslant tract (FAT) is a recently described WMT that runs orthogonal to the dominant direction of most tracts. 15 Connectomic mapping by our group and others suggests that the FAT has two primary functions: 1) link the supplementary motor area (SMA) to the premotor areas and area 44, and 2) link the middle cingulate portions of the salience network to the anterior insular portions. 15 Thus, it is not surprising that intraoperative FAT stimulation leads to language arrest while tractography studies have implicated FAT degeneration in nonfluent primary progressive aphasias.…”

Section: Observation 2: the Frontal Aslant Tract Is Eloquentmentioning

confidence: 98%

“…15 Connectomic mapping by our group and others suggests that the FAT has two primary functions: 1) link the supplementary motor area (SMA) to the premotor areas and area 44, and 2) link the middle cingulate portions of the salience network to the anterior insular portions. 15 Thus, it is not surprising that intraoperative FAT stimulation leads to language arrest while tractography studies have implicated FAT degeneration in nonfluent primary progressive aphasias. 16,17 In addition, recent data suggest that the FAT plays a key role in the genesis of postoperative SMA syndrome.…”

Section: Observation 2: the Frontal Aslant Tract Is Eloquentmentioning

confidence: 98%

The cortical organization of language: distilling human connectome insights for supratentorial neurosurgery

Poologaindran

Lowe

Sughrue

2021

Journal of Neurosurgery

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Connectomics is the production and study of detailed “connection” maps within the nervous system. With unprecedented advances in imaging and high-performance computing, the construction of individualized connectomes for routine neurosurgical use is on the horizon. Multiple projects, including the Human Connectome Project (HCP), have unraveled new and exciting data describing the functional and structural connectivity of the brain. However, the abstraction from much of these data to clinical relevance remains elusive. In the context of preserving neurological function after supratentorial surgery, abstracting surgically salient points from the vast computational data in connectomics is of paramount importance. Herein, the authors discuss four interesting observations from the HCP data that have surgical relevance, with an emphasis on the cortical organization of language: 1) the existence of a motor speech area outside of Broca’s area, 2) the eloquence of the frontal aslant tract, 3) the explanation of the medial frontal cognitive control networks, and 4) the establishment of the second ventral stream of language processing. From these connectome observations, the authors discuss the anatomical basis of their insights as well as relevant clinical applications. Together, these observations provide a firm platform for neurosurgeons to advance their knowledge of the cortical networks involved in language and to ultimately improve surgical outcomes. It is hoped that this report encourages neurosurgeons to explore new vistas in connectome-based neurosurgery.

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“…Previous localizationist views have suggested that this deficit occurs primarily due to surgical insult in the posteromedial bank of the superior frontal gyrus, yet other patients too demonstrate varying degrees of mutism and hemiplegia when operating outside this canonical SMA (14). Fortunately, further insight on the major connectivity of the medial frontal lobe has revealed that the FAT is the principle pathway linking the SMA to premotor areas and area 44 (Broca's area) and also links hubs of the salience network, supporting a possible role of the FAT in initiating motor or speech activity through its interconnections throughout the initiation axis (87,88). We have recently shown that by applying this knowledge in patients with gliomas in the SMA, intraoperative identification and subsequent preservation of the FAT can reduce SMA syndrome compared to just "avoiding the posterior bank of the SFG" (Figure 2).…”

Section: Using Brain Network Maps In Surgerymentioning

confidence: 99%

Reducing the Cognitive Footprint of Brain Tumor Surgery

et al. 2021

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The surgical management of brain tumors is based on the principle that the extent of resection improves patient outcomes. Traditionally, neurosurgeons have considered that lesions in “non-eloquent” cerebrum can be more aggressively surgically managed compared to lesions in “eloquent” regions with more known functional relevance. Furthermore, advancements in multimodal imaging technologies have improved our ability to extend the rate of resection while minimizing the risk of inducing new neurologic deficits, together referred to as the “onco-functional balance.” However, despite the common utilization of invasive techniques such as cortical mapping to identify eloquent tissue responsible for language and motor functions, glioma patients continue to present post-operatively with poor cognitive morbidity in higher-order functions. Such observations are likely related to the difficulty in interpreting the highly-dimensional information these technologies present to us regarding cognition in addition to our classically poor understanding of the functional and structural neuroanatomy underlying complex higher-order cognitive functions. Furthermore, reduction of the brain into isolated cortical regions without consideration of the complex, interacting brain networks which these regions function within to subserve higher-order cognition inherently prevents our successful navigation of true eloquent and non-eloquent cerebrum. Fortunately, recent large-scale movements in the neuroscience community, such as the Human Connectome Project (HCP), have provided updated neural data detailing the many intricate macroscopic connections between cortical regions which integrate and process the information underlying complex human behavior within a brain “connectome.” Connectomic data can provide us better maps on how to understand convoluted cortical and subcortical relationships between tumor and human cerebrum such that neurosurgeons can begin to make more informed decisions during surgery to maximize the onco-functional balance. However, connectome-based neurosurgery and related applications for neurorehabilitation are relatively nascent and require further work moving forward to optimize our ability to add highly valuable connectomic data to our surgical armamentarium. In this manuscript, we review four concepts with detailed examples which will help us better understand post-operative cognitive outcomes and provide a guide for how to utilize connectomics to reduce cognitive morbidity following cerebral surgery.

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A Connectomic Atlas of the Human Cerebrum—Chapter 14: Tractographic Description of the Frontal Aslant Tract

Cited by 22 publications

References 29 publications

The Frontal Aslant Tract: A Systematic Review for Neurosurgical Applications

The Frontal Aslant Tract: A Systematic Review for Neurosurgical Applications

The cortical organization of language: distilling human connectome insights for supratentorial neurosurgery

Reducing the Cognitive Footprint of Brain Tumor Surgery

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