The aim of this thesis was to identify functional biomarkers for migraine attack prediction based on neurophysiological readout parameters. The main focus of this work was on the development of... Show moreThe aim of this thesis was to identify functional biomarkers for migraine attack prediction based on neurophysiological readout parameters. The main focus of this work was on the development of methodologies to measure brain excitability over the migraine cycle, with special emphasis on identifying changes in excitability of the visual system and the occipital cortex. Applying such measures over the course of a migraine cycle could help elucidate factors that initiate the migraine attack, and might lead to better (or better timing of) preventive measures. The research described in this thesis is divided into two parts. The first part reports on the development and application of several methodologies to measure excitability of the visual system including the cortex in migraine patients and a migraine mouse model. The second part consists of two studies employing transcranial magnetic stimulation (TMS) in combination with concurrent electroencephalography (EEG) recordings to provide direct measures of cortical excitability in migraine and epilepsy. Show less
Objective: A sensorimotor network structural phenotype predicted motor task performance in a previous study in Huntington's disease (HD) gene carriers. We investigated in the visual network whether... Show moreObjective: A sensorimotor network structural phenotype predicted motor task performance in a previous study in Huntington's disease (HD) gene carriers. We investigated in the visual network whether structure - function - behaviour relationship patterns, and the effects of the HD mutation, extended beyond the sensorimotor network.Methods: We used multimodal visual network MRI structural measures (cortical thickness and white matter connectivity), plus visual evoked potentials and task performance (Map Search; Symbol Digit Modalities Test) in healthy controls and HD gene carriers.Results: Using principal component (PC) analysis, we identified a structure - function relationship common to both groups. PC scores differed between groups indicating white matter disorganization (higher RD, lower FA) and slower, and more disperse, VEP signal transmission (higher VEP P100 latency and lower VEP P100 amplitude) in HD than controls while task performance was similar.Conclusions: HD may be associated with reduced white matter organization and efficient visual network function but normal task performance.Significance: These findings indicate that structure - function relationships in the visual network, and the effects of the HD mutation, share some commonalities with those in the sensorimotor network. However, implications for task performance differ between the two networks suggesting the influence of network specific factors. (C) 2019 Published by Elsevier B.V. on behalf of International Federation of Clinical Neurophysiology. Show less
