Browsing by Subject "LAMC3"
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Item Open Access Cortical connectivity in the face of congenital structural changes—A case of homozygous LAMC3 mutation(John Wiley & Sons Ltd., 2021-08) Demirayak, P.; Oğuz, Kader Karlı; Üstün, Fatma Seyhun; Ürgen, Buse Merve; Topaç, Yasemin; Gilani, İrtiza; Kansu, T.; Saygı, S.; Özçelik, Tayfun; Boyacı, Hüseyin; Doerschner, KatjaThe 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.Item Open Access Genetic influences on cortical structure and function(2018-07) Demirayak, PınarStructure and function of the human central nervous system is determined by both genetic and environmental in uences. One of the fundamental quests in neuroscience studies is to determine to what degree each of these two factors in uence the development and function of the nervous system and, ultimately, human behavior. However, this is an inherently di cult problem to tackle as it is nearly impossible to tease apart the individual contributions of genes and environment, since they interact heavily throughout an organism's life. Recently, our understanding about the role that speci c genes play in the development of brain structure and function, has been greatly advanced by studies that combine genetic and neuroimaging methods to investigate congenital neurodevelopmental disorders. These studies of patients, that are homozygous for a speci c mutation, allow to single out contributions of individual genes in the neurodevelopmental process and have the potential to reveal gene-based alterations in cortical structure and function that can not be compensated by mechanisms of cortical plasticity or mitigating environmental e ects. In this thesis I pursue this promising approach further and investigate the e ects of three di erent single gene mutations on brain structure and function - namely RAD51, LAMC3 and HTRA2. Each of these genes is highly expressed during neurodevelopment, and each in uences cortical structure and function di erently. Overall, I nd that these genes are all highly associated with abnormal structural and functional connectivity patterns, however, and surprisingly, highly abnormal structure does not necessarily predict highly abnormal behavior.