Mapping the human middle longitudinal fasciculus through a focused anatomo-imaging study: shifting the paradigm of its segmentation and connectivity pattern

Kalyvas, Aristotelis; Komaitis, Spyridon; Karavasilis, Efstratios; Christidi, Foteini; Skandalakis, Georgios P.; Liouta, Evangelia; Papakonstantinou, Olympia; Kelekis, Nikolaos; Duffau, Hugues; Stranjalis, George

doi:10.1007/s00429-019-01987-6

Cited by 37 publications

(46 citation statements)

References 140 publications

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“…2019 ) or middle longitudinal fasciculus ( Makris et al. 2017 ; Kalyvas et al. 2020 ), are tracts disconnected in association with apraxia severity.…”

Section: Discussionmentioning

confidence: 99%

Structural Disconnection of the Tool Use Network after Left Hemisphere Stroke Predicts Limb Apraxia Severity

Garcea

Greene

Grafton

et al. 2020

Cerebral Cortex Communications

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Producing a tool use gesture is a complex process drawing upon the integration of stored knowledge of tools and their associated actions with sensory-motor mechanisms supporting the planning and control of hand and arm actions. Understanding how sensory-motor systems in parietal cortex interface with semantic representations of actions and objects in the temporal lobe remains a critical issue, and is hypothesized to be a key determinant of the severity of limb apraxia, a deficit in producing skilled action after left hemisphere stroke. We used voxel-based and connectome-based lesion symptom mapping with data from 57 left hemisphere stroke participants to assess the lesion sites and structural disconnection patterns associated with poor tool use gesturing. We found that structural disconnection among the left inferior parietal lobule, lateral and ventral temporal cortex, and middle and superior frontal gyri predicted the severity of tool use gesturing performance. Control analyses demonstrated that reductions in right-hand grip strength were associated with motor system disconnection, largely bypassing regions supporting tool use gesturing. Our findings provide causal evidence that limb apraxia may arise, in part, from a disconnection between conceptual representations in the temporal lobe and mechanisms enabling skilled action production in the inferior parietal lobule.

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“…2019 ) or middle longitudinal fasciculus ( Makris et al. 2017 ; Kalyvas et al. 2020 ), are tracts disconnected in association with apraxia severity.…”

Section: Discussionmentioning

confidence: 99%

Structural Disconnection of the Tool Use Network after Left Hemisphere Stroke Predicts Limb Apraxia Severity

Garcea

Greene

Grafton

et al. 2020

Cerebral Cortex Communications

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“…It has been demonstrated that, under certain conditions of scientific rigor, in-vivo tractography helps to clarify the organization of white matter anatomy otherwise left unresolved by post-mortem methods (Takemura et al 2016b;Takemura et al 2019;Wandell 2016;Sani et al 2019;Yeatman et al 2014;Puzniak et al 2019;Takemura et al 2017;Leong et al 2016). Furthermore, recent examples have appeared where tractography has led the way by shedding light to undescribed anatomy with postmortem work providing independent validation Kalyvas et al 2019).…”

Section: Discussionmentioning

confidence: 99%

The visual white matter connecting human area prostriata and the thalamus is retinotopically organized

Kurzawski

Mikellidou

Morrone

et al. 2020

Preprint

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The human visual system is capable of processing visual information from fovea to the far peripheral visual field. Recent fMRI studies have shown a full and detailed retinotopic map in area prostriata, located ventro-dorsally and anterior to the calcarine sulcus along the parietooccipital sulcus with strong preference for peripheral and wide-field stimulation. Here, we report the anatomical pattern of white-matter connections between area prostriata and the thalamus encompassing the lateral geniculate nucleus (LGN). We observe a continuous and extended bundle of white matter fibers from which two subcomponents can be extracted: one passing ventrally parallel to the optic radiations (OR) and another passing dorsally circumventing the lateral ventricle. Interestingly, the loop travelling dorsally connects the thalamus with the central visual field representation of prostriata, while the other loop travelling more ventrally connects the LGN with the more peripheral visual field representation. This is consistent with a retinotopic segregation recently demonstrated in the OR, connecting the LGN and V1 in humans. Our results demonstrate for the first time a retinotopic segregation regarding the trajectory of a fiber bundle between the thalamus and an associative visual area.

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“…Middle longitudinal fascicle anterior terminations at the level of the STG and temporal pole (TP) are also controversial, as some authors found these terminations to reach the most anterior cortex of STG and TP (Makris et al, 2013a,b;Wang et al, 2013;Kalyvas et al, 2020), while others described a more posterior origin of MdLF fibers (Conner et al, 2018) or at least a less organized bundle with less numerous fibers at the level of TP (Maldonado et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…While DTI studies showed several subcomponents (up to six) of the MdLF (Makris et al, 2017), white matter dissection studies showed either a single bundle from the STG to posterior terminations or two components with a deeper layer of fibers originating more anteriorly and suggesting a segmentation pattern in the MdLF (Maldonado et al, 2013;Wang et al, 2013). More recently three subcomponents with different connection patterns have been described by Kalyvas et al (2020).…”

Section: Introductionmentioning

confidence: 99%

“…The functional role of the MdLF is even less understood than its morphology. Some authors, on the basis of the cortical terminations, speculated that this bundle might be a connection between the dorsal and ventral stream of the language network (Saur et al, 2008), while others identified the MdLF as the potential pathway for the dorsal auditory stream (Wang et al, 2013;Kalyvas et al, 2020), as well as for ventral auditory stream. Others have speculated that functions are related to language comprehension, visuospatial and attention functions, and integration between auditory and visual information (Makris et al, 2017;Kalyvas et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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New Insights Into the Anatomy, Connectivity and Clinical Implications of the Middle Longitudinal Fasciculus

et al. 2021

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The middle longitudinal fascicle (MdLF) is a long, associative white matter tract connecting the superior temporal gyrus (STG) with the parietal and occipital lobe. Previous studies show different cortical terminations, and a possible segmentation pattern of the tract. In this study, we performed a post-mortem white matter dissection of 12 human hemispheres and an in vivo deterministic fiber tracking of 24 subjects acquired from the Human Connectome Project to establish whether a constant organization of fibers exists among the MdLF subcomponents and to acquire anatomical information on each subcomponent. Moreover, two clinical cases of brain tumors impinged on MdLF territories are reported to further discuss the anatomical results in light of previously published data on the functional involvement of this bundle. The main finding is that the MdLF is consistently organized into two layers: an antero-ventral segment (aMdLF) connecting the anterior STG (including temporal pole and planum polare) and the extrastriate lateral occipital cortex, and a posterior-dorsal segment (pMdLF) connecting the posterior STG, anterior transverse temporal gyrus and planum temporale with the superior parietal lobule and lateral occipital cortex. The anatomical connectivity pattern and quantitative differences between the MdLF subcomponents along with the clinical cases reported in this paper support the role of MdLF in high-order functions related to acoustic information. We suggest that pMdLF may contribute to the learning process associated with verbal-auditory stimuli, especially on left side, while aMdLF may play a role in processing/retrieving auditory information already consolidated within the temporal lobe.

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Mapping the human middle longitudinal fasciculus through a focused anatomo-imaging study: shifting the paradigm of its segmentation and connectivity pattern

Cited by 37 publications

References 140 publications

Structural Disconnection of the Tool Use Network after Left Hemisphere Stroke Predicts Limb Apraxia Severity

Structural Disconnection of the Tool Use Network after Left Hemisphere Stroke Predicts Limb Apraxia Severity

The visual white matter connecting human area prostriata and the thalamus is retinotopically organized

New Insights Into the Anatomy, Connectivity and Clinical Implications of the Middle Longitudinal Fasciculus

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