White matter architecture of the language network

Abstract

The relevance of anatomical connectivity for understanding of the neural basis of language was recognized in the 19 th century, and yet this topic has only recently become the subject of wider research interest. In this paper, I review recent findings on white matter tracts implicated in language: the arcuate fasciculus, superior longitudinal fasciculus, extreme capsule, uncinate fasciculus, middle longitudinal fasciculus, inferior longitudinal fasciculus, and inferior fronto-occipital fasciculus. The reviewed findings on these tracts were reported in studies that used a variety of methods, from post-mortem dissection and diffusion imaging to intraoperative electrostimulation with awake surgery patients. The emerging picture suggests that there is currently no consensus with regard to the exact number and identity of the tracts supporting language, their origins, trajectories, and terminations, as well as their functional interpretation.

Dorsal White Matter Integrity and Name Retrieval in Midlife

“…The SLF is a complex fiber system, whose one component connects inferior frontal and inferior parietal areas [21,22]. Previous research has emphasized the role of the uncinate fasciculus in proper name retrieval [23,24], which is consistent with the evidence on the role of the anterior temporal lobe in naming [12], given the fact that the uncinate fasciculus links the temporal pole with orbito-frontal areas [27,42,43]. Thus, a possible association of the SLF and naming would provide evidence for the relevance of the dorsal white matter to name retrieval.…”

“…According to the traditional view, the left arcuate fasciculus is the classical language pathway, connecting Broca's and Wernicke's areas. On the other hand, according to one currently prominent view, the superior longitudinal fasciculus is a complex fiber system [52], consisting of four components in the human brain (see [43] for a review). In this multicomponent system view, the arcuate fasciculus is a part of the superior longitudinal fasciculus system [21,22].…”

Machine-learning classification of 22q11.2 deletion syndrome: A diffusion tensor imaging study

“…In non-human primates, the EmC has been found to connect the inferior frontal gyrus, which is the equivalent to Broca's area in humans in the frontal lobe, with the human equivalent of Wernicke's area in the temporal lobe ( Schmahmann and Pandya, 2006 ). Although this precise a connection can only be inferred on diffusion weighted images, it has led investigators to hypothesize that the EmC supports semantic and syntactic comprehension, thus constituting a core language pathway ( Kellmeyer et al, 2013 , Kljajevic, 2014 , Makris and Pandya, 2009 , Saur et al, 2008 ). Our observations suggested associations between metrics of the EmC and Composite scores of the WAIS-III, but again, these scores represent an amalgam of skills, and their association with the EmC was not specific.…”

White matter asymmetries in patients with cerebral small vessel disease

“…For example, the right-handed group had higher FA values in the left precentral gyrus [2]. The FA values of left internal capsule (posterior limb) [3], inferior longitudinal fasciculus [4], cingulum [5,6], and superior longitudinal fasciculus [7] were greater than the FA values of the right arcuate fasciculus [4,8] and the right internal capsule (anterior limb) [9]. However, the hemispheric asymmetry of FA mostly existed in healthy juveniles.…”