Cortical connectivity in the face of congenital structural changes—A case of homozygous LAMC3 mutation

• Published in: Brain and behavior Vol. 11; no. 8; pp. e2241 - n/a
• Main Authors: Demirayak, Pinar, Karli Oguz, Kader, Ustun, Fatma Seyhun, Urgen, Buse Merve, Topac, Yasemin, Gilani, Irtiza, Kansu, Tulay, Saygi, Serap, Ozcelik, Tayfun, Boyaci, Huseyin, Doerschner, Katja
• Format: Journal Article
• Language: English
• Published: Los Angeles John Wiley & Sons, Inc 01.08.2021; John Wiley and Sons Inc; Wiley
• Subjects: diffusion tensor imaging; functional connectivity; LAMC3; Mutation; Original Research; probabilistic tracktography; resting state; structural connectivity
• ISSN: 2162-3279; 2162-3279
• DOI: 10.1002/brb3.2241

The homozygous LAMC3 gene mutation is associated with severe bilateral smoothening and thickening of the lateral occipital cortex . Despite this and further significant changes in gray matter structure, a patient harboring this mutation exhibited a range of remarkably intact perceptual abilities . One possible explanation of this perceptual sparing could be that the white matter structural integrity and functional connectivity in relevant pathways remained intact. To test this idea, we used diffusion tensor and functional magnetic resonance imaging to investigate functional connectivity in resting‐state networks in major structural pathways involved in object perception and visual attention and corresponding microstructural integrity in a patient with homozygous LAMC3 mutation and sex, age, education, and socioeconomically matched healthy control group. White matter microstructural integrity results indicated widespread disruptions in both intra‐ and interhemispheric structural connections except inferior longitudinal fasciculus. With a few exceptions, the functional connectivity between the patient's adjacent gray matter regions of major white matter tracts of interest was conserved. In addition, functional localizers for face, object, and place areas showed similar results with a representative control, providing an explanation for the patient's intact face, place, and object recognition abilities. To generalize this finding, we also compared functional connectivity between early visual areas and face, place, and object category‐selective areas, and we found that the functional connectivity of the patient was not different from the control group. Overall, our results provided complementary information about the effects of LAMC3 gene mutation on the human brain including intact temporo‐occipital structural and functional connectivity that are compatible with preserved perceptual abilities. While structural results predominantly point to widespread disruptions in intrahemispheric and interhemispheric connectivity, functional connectivity seemed to have been conserved, especially between left inferior temporo‐occipital areas including the inferior temporal gyrus and the lateral occipital cortex. These functional results could provide an explanation for the patient's intact face and object recognition abilities. Taken together our findings serve as a striking example of the brain's ability to maintain normal function in the face of gross congenital structural changes, and that the relation between cortical structure and function is not necessarily isomorphic.