Απεικόνιση λειτουργίας ζωτικών κέντρων του εγκεφάλου με χρήση λειτουργικής μαγνητικής τομογραφίας εγκεφάλου (f MRI) και τομογραφίας εκπομπής ποζιτρονίων (PET) σε άτομα με μαθησιακές διαταραχές

Abstract

This systematic review aims to highlight the contribution of medical imaging methods used in neuroscientific research in the field of learning disorders. More specifically, special emphasis has been given on functional Magnetic Resonance imaging (fMRI) and Positron Emission Tomography (PET), as these two techniques are able to provide functional imaging of the brain and to highlight any under-or-over activity of specific anatomical areas, which are associated with various learning disorders. This is a fact of paramount importance, since by decoding the structures of the brain and correlating their function with the development of learning disorders, human intervention becomes possible, both theoretically and practically-invasively, in order to improve the quality of life of persons with a history of learning disabilities. The study was carried out with a critical view of the literature on the specific topic and on a defined set of scientific articles and researches from valid electronic sources published in the last 20 years. The various evaluation techniques of the studied sources were compared based on their methodology, results and commentary. This post-graduate thesis is developed in four chapters. Each of them plays a key-role in providing the necessary information, so that what is analyzed in the following chapters can be easily understood. The first chapter refers to the anatomy and physiology of the brain while extensive reference is given to the central nervous system, since it includes the brain. The subsection of brain anatomy analyzes the most important structures that play a crucial role in the development of learning disorders, while that of physiology describes the function they normally perform, so that the reader can understand their dysfunction in any learning disorder. The second chapter deals with brain imaging techniques. Here, the main imaging techniques are analyzed, while special emphasis is placed on the two main functional imaging techniques: the functional Magnetic Resonance Imaging (fMRI) and the Positron Emission Tomography (PET). These techniques, while using completely different medical technology, are able to depict at a molecular level the function of cells and therefore the various structures of the brain, which makes them particularly valuable. The functional Magnetic Resonance Imaging (fMRI) uses radio frequency pulses and offers functional imaging, in addition to anatomical imaging, high spatial resolution. The Positron Emission Tomography (PET) uses indirect ionizing radiation-γ (derived from the interaction of positrons with electrons). The third chapter describes and analyzes both learning disorders and their grading, so that the reader is introduced to the complex world of learning difficulties. Here, special reference is made to the main definitions of learning disabilities and disorders while also, a brief reference is made to their etiology. Finally, the fourth chapter is the essence of this study and includes extensive reports of symptoms, characteristics and causes for the already analyzed learning disorders. Additionally, by using scientific references made by past researches, all the brain anatomical structures that play an important role in the aforementioned learning disorders are presented. Their specific role is also examined. The purpose of this thesis is to study and understand the highly complex processes that support the development of learning and to investigate the causes of developmental disorders, in the light of neuroimaging and specifically functional neuroimaging.