Heschl’s gyrus fiber intersection area: a new insight on the connectivity of the auditory-language hub

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>The functional importance of the superior temporal lobe at the level of Heschl’s gyrus is well known. However, the organization and function of these cortical areas and the underlying fiber tracts connecting them remain unclear. The goal of this study was to analyze the area formed by the organization of the intersection of Heschl’s gyrus–related fiber tracts, which the authors have termed the “Heschl’s gyrus fiber intersection area” (HGFIA).</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>The subcortical connectivity of Heschl’s gyrus tracts was analyzed by white matter fiber dissection and by diffusion tensor imaging tractography. The white matter tracts organized in relation to Heschl’s gyrus were isolated in 8 human hemispheres from cadaveric specimens and in 8 MRI studies in 4 healthy volunteers. In addition, these tracts and their functions were described in the surgical cases of left temporal gliomas next to the HGFIA in 6 patients who were awake during surgery and underwent intraoperative electrical stimulation mapping.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Five tracts were observed to pass through the HGFIA: the anterior segment of the arcuate fasciculus, the middle longitudinal fasciculus, the acoustic radiation, the inferior fronto-occipital fasciculus, and the optic radiation. In addition, U fibers originating at the level of Heschl’s gyrus and heading toward the middle temporal gyrus were identified.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>This investigation of the HGFIA, a region where 5 fiber tracts intersect in a relationship with the primary auditory area, provides new insights into the subcortical organization of Wernicke’s area. This information is valuable when a temporal surgical approach is planned, in order to assess the surgical risk related to language disturbances.</jats:p></jats:sec>

Gray matter atrophy and corresponding impairments in connectivity in patients with anti-N-methyl-D-aspartate receptor encephalitis

“…As we know, verbal working memory is divided into phonological store and articulatory rehearsal (Baddeley, 1992). The Heschl gyrus is a major component of the superior temporal gyrus and forms the primary auditory region (Fernandez et al, 2020); the IFG is also considered to play an important role in auditory and visual verbal information processing (Liu X et al, 2012;Zhu et al, 2020). Therefore, these two brain regions are both related to verbal working memory, thus supporting our observations.…”

A review of the anatomy and function of the white matter tracts in language production and comprehension

“…Complementing these, are studies of intraoperative stimulation of ILF/IFOF. The majority of such studies have found IFOF stimulation to cause semantic paraphasias (Almairac et al, 2015;Duffau, 2015;2009;Fernández et al, 2020;Gil-Robles et al, 2013;Mandonnet et al, 2007;Moritz-Gasser et al, 2013;Motomura et al, 2018;2014). ILF's role is more contested; some have found ILF stimulation to cause omission errors (Herbet et al, 2019) and some have found no adverse effect on language production when stimulating this tract (e.g., Gil-Robles et al, 2013;Mandonnet et al, 2007;Moritz-Gasser et al, 2013).…”

Editorial. Probing the tract organization of language: Heschl’s gyrus fiber intersection area

“…In this article, Fernández, Velásquez, García Porrero, Marco de Lucas, and Martino present converging evidence from cadaveric fiber dissections, in vivo diffusion MRI tractography, and intraoperative subcortical stimulation to describe the complex white matter architecture in the posterior region of the superior temporal lobe around Heschl's gyrus and the acoustic radiations. 5 The authors performed detailed dissections in 8 cadaveric hemispheres (4 left and 4 right). They also acquired and analyzed data from diffusion MRI probabilistic tractography in 8 control hemispheres from 4 healthy subjects and intraoperative electrical stimulation mapping in 6 patients with left temporal lobe gliomas who underwent awake resections.…”