By monitoring ongoing actions and performance outcomes, we are able to detect errors or mismatches between our intentions or predictions. Disturbances in such performance-monitoring processes may... Show moreBy monitoring ongoing actions and performance outcomes, we are able to detect errors or mismatches between our intentions or predictions. Disturbances in such performance-monitoring processes may importantly contribute to impaired adaptive behavior in clinical disorders, such as excessively impulsive behavior in externalizing disorders or excessively rigid or careful behavior in anxiety- and obsessive-compulsive disorders. In daily life, performance monitoring often takes place in a social context, where our actions have consequences not only for ourselves, but also for others. The investigation of (alterations in) such (pro)social performance-monitoring processes may help explain functional and social impairments across a wide range of clinical disorders. In this dissertation, we used various neuroimaging paradigms to examine subclinical and neurochemical influences on performance monitoring when errors had consequences for oneself or others. The studies in this dissertation indicate that neural performance-monitoring correlates are modulated by social, subclinical, and neurochemical factors, including social (responsibility) context, obsessive-compulsive symptoms, ovarian hormones, and pharmacological manipulations of dopamine and oxytocin. These findings have implications for the potential and utility of error-related brain activity as a clinical biomarker or endophenotype, our insight into social symptoms and impairments in obsessive-compulsive disorder, and for our understanding of the neurochemical mechanisms underlying performance monitoring. Show less
Migraine is associated with altered sensory processing, that may be evident as changes in cortical responsivity due to altered excitability, especially in migraine with aura. Cortical excitability... Show moreMigraine is associated with altered sensory processing, that may be evident as changes in cortical responsivity due to altered excitability, especially in migraine with aura. Cortical excitability can be directly assessed by combining transcranial magnetic stimulation with electroencephalography (TMS-EEG). We measured TMS evoked potential (TEP) amplitude and response consistency as these measures have been linked to cortical excitability but were not yet reported in migraine.We recorded 64-channel EEG during single-pulse TMS on the vertex interictally in 10 people with migraine with aura and 10 healthy controls matched for age, sex and resting motor threshold. On average 160 pulses around resting motor threshold were delivered through a circular coil in clockwise and counterclockwise direction. Trial-averaged TEP responses, frequency spectra and phase clustering (over the entire scalp as well as in frontal, central and occipital midline electrode clusters) were compared between groups, including comparison to sham-stimulation evoked responses.Migraine and control groups had a similar distribution of TEP waveforms over the scalp. In migraine with aura, TEP responses showed reduced amplitude around the frontal and occipital N100 peaks. For the migraine and control groups, responses over the scalp were affected by current direction for the primary motor cortex, somatosensory cortex and sensory association areas, but not for frontal, central or occipital midline clusters.This study provides evidence of altered TEP responses in-between attacks in migraine with aura. Decreased TEP responses around the N100 peak may be indicative of reduced cortical GABA-mediated inhibition and expand observations on enhanced cortical excitability from earlier migraine studies using more indirect measurements. Show less
Speaking more than one language has a profound impact on both the mind and the brain. But how does the multilingual brain manage a native language as well as a non-native language, specifically... Show moreSpeaking more than one language has a profound impact on both the mind and the brain. But how does the multilingual brain manage a native language as well as a non-native language, specifically when the non-native language was acquired later in development? In this thesis, we aimed to characterise the multilingual experience of late language learners in three ways. First, we examined how the cross-linguistic influence (CLI) between the native language and the non-native language influenced non-native comprehension and production. Second, we compared different multilingual populations to quantify the impact of language similarity on CLI and non-native comprehension and production. Third, we examined whether language similarity played a modulating role beyond language processing in terms of domain-general inhibitory control. These are critical issues because they speak directly to the notion of how the native language and the non-native language co-exist in the brain. Further, they help us characterise the functional organisation of these languages in the multilingual brain. Across several studies, we systematically explored these three issues by using several experimental paradigms and a combination of behavioural and electroencephalographic measures. Subsequently, we pushed the theoretical boundaries of the issues in question and contributed novel evidence to this area of research. Show less
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
Patients with Parkinson's Disease may be eligible for Deep Brain Stimulation (DBS) in case of severe motor complications. This thesis provides indications for improving patient selection for DBS,... Show morePatients with Parkinson's Disease may be eligible for Deep Brain Stimulation (DBS) in case of severe motor complications. This thesis provides indications for improving patient selection for DBS, as well as describing new biomarkers based on Electroencephalography (EEG) to aid during the DBS selection process. Show less
Prematurely born children are at higher risk for long-term adverse motor and cognitive outcomes. The aim of this paper was to compare quantitative measures derived from electroencephalography (EEG)... Show morePrematurely born children are at higher risk for long-term adverse motor and cognitive outcomes. The aim of this paper was to compare quantitative measures derived from electroencephalography (EEG) between extremely (EP) and very prematurely (VP) born children at 9-10 years of age.Fifty-five children born < 32 weeks' of gestation underwent EEG at 9-10 years of age and were assessed for motor development and cognitive outcome. Relative frequency power and functional connectivity, as measured by the Phase Lag Index (PLI), were calculated for all frequency bands. Per subject, power spectrum and functional connectivity results were averaged over all channels and pairwise PLI values to explore differences in global frequency power and functional connectivity between EP and VP children. Brain networks were constructed for the upper alpha frequency band using the Minimum Spanning Tree method and were compared between EP and VP children. In addition, the relationships between upper alpha quantitative EEG results and cognitive and motor outcomes were investigated.Relative power and functional connectivity were significantly higher in VP than EP children in the upper alpha frequency band, and VP children had more integrated networks. A strong positive correlation was found between relative upper alpha power and motor outcome whilst controlling for gestational age, age during EEG recording, and gender (p = 0.493, p = 0.004).These results suggest that 9-10 years after birth, the effects of the degree of prematurity can be observed in terms of alterations in functional brain activity and that motor deficits are associated with decreases in relative upper alpha power. Show less
this thesis investigates a family with autosomal dominant neuronal ceroid lipofuscinosis, with chapters on clinical neurology, neuropathology, neurogenetics, neurophysiology, auditory and visual... Show morethis thesis investigates a family with autosomal dominant neuronal ceroid lipofuscinosis, with chapters on clinical neurology, neuropathology, neurogenetics, neurophysiology, auditory and visual aspects. Show less
