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Detection of the arcuate fasciculus in congenital amusia depends on the tractography algorithm
Journal article   Open access   Peer reviewed

Detection of the arcuate fasciculus in congenital amusia depends on the tractography algorithm

Joyce L. Chen, Sukhbinder Kumar, Victoria J. Williamson, Jan Scholz, Timothy D. Griffiths and Lauren Stewart
Frontiers in psychology, Vol.6, pp.9-9
01/21/2015
DOI: 10.3389/fpsyg.2015.00009
PMCID: PMC4300860
PMID: 25653637
url
https://doi.org/10.3389/fpsyg.2015.00009View
Published (Version of record) Open Access

Abstract

The advent of diffusion magnetic resonance imaging (MRI) allows researchers to virtually dissect white matter fiber pathways in the brain in vivo . This, for example, allows us to characterize and quantify how fiber tracts differ across populations in health and disease, and change as a function of training. Based on diffusion MRI, prior literature reports the absence of the arcuate fasciculus (AF) in some control individuals and as well in those with congenital amusia. The complete absence of such a major anatomical tract is surprising given the subtle impairments that characterize amusia. Thus, we hypothesize that failure to detect the AF in this population may relate to the tracking algorithm used, and is not necessarily reflective of their phenotype. Diffusion data in control and amusic individuals were analyzed using three different tracking algorithms: deterministic and probabilistic, the latter either modeling two or one fiber populations. Across the three algorithms, we replicate prior findings of a left greater than right AF volume, but do not find group differences or an interaction. We detect the AF in all individuals using the probabilistic 2-fiber model, however, tracking failed in some control and amusic individuals when deterministic tractography was applied. These findings show that the ability to detect the AF in our sample is dependent on the type of tractography algorithm. This raises the question of whether failure to detect the AF in prior studies may be unrelated to the underlying anatomy or phenotype.
arcuate fasciculus congenital amusia crossing fibers deterministic diffusion magnetic resonance imaging probabilistic Psychology tractography

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