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Explaining the Link Between Dyslexia Susceptibility Genes DYX1C1, DCDC2 and KIAA0319 and Variation in Brain Activity in the Middle Temporal Gyrus, Intraparietal Sulcus and Inferior Frontal Gyrus during reading tasks

Show simple item record 2022-08-24T09:47:07Z 2022-08-24T09:47:07Z 2022-08-24
dc.title Explaining the Link Between Dyslexia Susceptibility Genes DYX1C1, DCDC2 and KIAA0319 and Variation in Brain Activity in the Middle Temporal Gyrus, Intraparietal Sulcus and Inferior Frontal Gyrus during reading tasks en
ethesis.faculty Lääketieteellinen tiedekunta fi
ethesis.faculty Faculty of Medicine en
ethesis.faculty Medicinska fakulteten sv
ethesis.faculty.URI Helsingin yliopisto fi University of Helsinki en Helsingfors universitet sv
dct.creator Rinne, Nea
dct.issued 2022
dct.abstract Aims: Reading ability is a fundamental skill in the modern society, yet some individuals have difficulties in learn-ing to read and write. There is a lot of variability in reading skills, and one reason that can cause reading difficulty is a neurodevelopmental disorder called dyslexia. It is the most common learning disability, and the core deficit in dyslexia lies in word decoding, which is the process of connecting letter combinations into their corresponding auditory representations. Dyslexia is familial and is recognized to have strong genetic background. A dozen dyslexia susceptibility genes have been suggested, but DYX1C1, DCDC2 and KIAA0319 have been associated with dyslexia most commonly. The function of these genes is however not yet fully understood. In previous studies variation in these genes have been linked to struc-tural brain alterations in left hemispheric regions where language is mostly processed. The aim of this study was to examine the connection between dyslexia susceptibility genes DCDC2, DYX1C1 and KI-AA0319 and variation in brain activity during reading tasks in the left middle temporal gyrus (MTG), infe-rior Frontal Gyrus (IFG) and intraparietal sulcus (IPS), by combining functional magnetic resonance imag-ing data and genetic data in a neurotypical population. Previous studies have reported that weaker reading skills are associated with decreased brain activity in these regions, and reading incongruent sentences has been associated with increased brain activity in the left IFG and MTG. Methods: During fMRI, participants were presented with sentences with illogical and logical endings, and judged them as either congruent or incongruent, in distracted and undistracted conditions. Auditory speech stimuli were used as distractor. Regions of Interest analyses were conducted to examine brain activation in the aforementioned brain regions during distracted and non-distracted reading separately for different allelic groups in single nucleotide polymorphisms of the three genes. Results and Conclusions: DYX1C1 showed significant interaction with brain activation in the IPS. A significant interaction of DCDC2 with logic was found in the IFG and IPS showing that individuals carrying susceptibility alleles have reduced brain activation when reading incongruent sentences. Additionally, DCDC2 showed inter-action with distraction in the IFG, as individuals carrying susceptibility alleles had reduced brain activa-tion when a speech distractor was presented. In the MTG, there was a significant interaction of DCDC2 with logic and distractor showing that in different allelic groups, speech distractor modulated the activa-tion elicited by incongruent sentences in different ways. These results provide a link between variation in dyslexia susceptibility genes and brain activation during reading. Previous studies have mostly linked dyslexia susceptibility genes to structural brain alterations, and dyslexia and lower reading skills have been linked to variation in brain activity. The current study therefore expands the current understanding of genetic basis on reading and linguistic processing. en
dct.subject Dyslexia
dct.subject fMRI
dct.subject DYX1C1
dct.subject DCDC2
dct.subject KIAA0319
dct.subject intraparietal sulcus (IPS)
dct.subject inferior frontal gyrus (IFG)
dct.subject middle temporal gyrus (MTG)
ethesis.language englanti fi
ethesis.language English en
ethesis.language engelska sv
ethesis.supervisor Patrik Wikman und
ethesis.thesistype pro gradu -tutkielmat fi
ethesis.thesistype master's thesis en
ethesis.thesistype pro gradu-avhandlingar sv
dct.identifier.ethesis E-thesisID:c9fdb612-f5ce-4231-8df7-f9acf0c27741
ethesis-internal.timestamp.reviewStep 2022-06-10 14:21:00:649
dct.identifier.urn URN:NBN:fi:hulib-202208243343 Psykologia und Neuroscience und
ethesis.facultystudyline Neuroscience and psychobiology fi
ethesis.facultystudyline Neuroscience and psychobiology en
ethesis.facultystudyline Neuroscience and psychobiology sv
ethesis.mastersdegreeprogram Translationaalisen lääketieteen maisteriohjelma (Translational Medicine) fi
ethesis.mastersdegreeprogram Master's Programme in Translational Medicine en
ethesis.mastersdegreeprogram Magisterprogrammet i translationell medicin sv

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