Predictive processes and numerous cognitive, motor, and social skills depend heavily on sequence learning. The visuomotor Serial Reaction Time Task (SRTT) can measure this fundamental cognitive process. To comprehend the neural underpinnings of the SRTT, non-invasive brain stimulation stands out as one of the most effective methodologies.
View Article and Find Full Text PDFIgG4-related (IgG4-RD) disease is a relatively newly identified, chronic autoimmune disorder that can affect any organ system. The disease is relatively rare. It has mostly systemic presentation, however it can also appear in isolated form in one single organ.
View Article and Find Full Text PDFBackground And Purpose: Therapeutic strategy of relapse-remitting multiple sclerosis has changed significantly during the past decade. While earlier escalating therapy was widely applied, recently, in case of high disease activity, induction therapy has become available.
Methods: In our study, we processed the data of our alemtuzumab treated patients from our register.
Parkinson's disease dysgraphia (PDYS), one of the earliest signs of Parkinson's disease (PD), has been researched as a promising biomarker of PD and as the target of a noninvasive and inexpensive approach to monitoring the progress of the disease. However, although several approaches to supportive PDYS diagnosis have been proposed (mainly based on handcrafted features (HF) extracted from online handwriting or the utilization of deep neural networks), it remains unclear which approach provides the highest discrimination power and how these approaches can be transferred between different datasets and languages. This study aims to compare classification performance based on two types of features: features automatically extracted by a pretrained convolutional neural network (CNN) and HF designed by human experts.
View Article and Find Full Text PDFBackground: Fingolimod was approved and reimbursed by the healthcare provider in Hungary for the treatment of highly active relapsing-remitting multiple sclerosis (RRMS) in 2012. The present study aimed to assess the effectiveness, safety profile, and persistence to fingolimod in a real-life setting in Hungary in RRMS patients who were either therapy naïve before enrollment or have changed to fingolimod from another disease-modifying therapy (DMT) for any reason.
Methods: This cross-sectional, observational study with prospective data collection was performed nationwide at 21 sites across Hungary.
Introduction: Multiple Sclerosis (MS) is the most common immune-mediated chronic neurodegenerative disease of the central nervous system (CNS) affecting young people. This is due to the permanent disability, cognitive impairment, and the enormous detrimental impact MS can exert on a patient's health-related quality of life. It is of great importance to recognise it in time and commence adequate treatment at an early stage.
View Article and Find Full Text PDFObjective: Lateralization of visuospatial attention in healthy people, known as pseudoneglect, results in leftward bias during the Landmark or line bisection tasks. Cognitive dysfunctions in patients with multiple sclerosis (MS) might affect the visuospatial attentional abilities as well. In this study, we aimed to examine the association between atrophy and lesion location and the extent of lateralization of visuospatial attentional bias in patients with MS.
View Article and Find Full Text PDFBackground: Recent advances in therapeutic options may prevent deterioration related to Huntington's disease (HD), even at the pre-symptomatic stage. Be that as it may, a well-characterized patient population is essential for screening and monitoring outcome. Accordingly, the aim of this study was to describe the characteristics of a Hungarian subpopulation of HD patients and mutation carriers diagnosed at the University of Szeged.
View Article and Find Full Text PDFThe threshold-free cluster enhancement (TFCE) approach integrates cluster information into voxel-wise statistical inference to enhance detectability of neuroimaging signal. Despite the significantly increased sensitivity, the application of TFCE is limited by several factors: (i) generalisation to data structures, like brain network connectivity data is not trivial, (ii) TFCE values are in an arbitrary unit, therefore, P-values can only be obtained by a computationally demanding permutation-test. Here, we introduce a probabilistic approach for TFCE (pTFCE), that gives a simple general framework for topology-based belief boosting.
View Article and Find Full Text PDFBilateral common carotid artery occlusion (BCCAo) in the rat is a widely used animal model of vascular dementia and a valuable tool for preclinical pharmacological drug testing, although the varying degrees of acute focal ischemic lesions it induces could interfere with its translational value. Recently, a modification to the BCCAo model, the stepwise occlusion of the two carotid arteries, has been introduced. To acquire objective translatable measures, we used longitudinal multimodal magnetic resonance imaging (MRI) to assess the effects of semi-chronic (8 days) donepezil treatment in this model, with half of the Wistar rats receiving the treatment one week after the stepwise BCCAo.
View Article and Find Full Text PDFVisual categorization plays an important role in fast and efficient information processing; still the neuronal basis of fast categorization has not been established yet. There are two main hypotheses known; both agree that primary, global impressions are based on the information acquired through the magnocellular pathway (MC). It is unclear whether this information is available through the MC that provides information (also) for the ventral pathway or through top-down mechanisms by connections between the dorsal pathway and the ventral pathway via the frontal cortex.
View Article and Find Full Text PDFAudio-visual integration has been shown to be present in a wide range of different conditions, some of which are processed through the dorsal, and others through the ventral visual pathway. Whereas neuroimaging studies have revealed integration-related activity in the brain, there has been no imaging study of the possible role of segregated visual streams in audio-visual integration. We set out to determine how the different visual pathways participate in this communication.
View Article and Find Full Text PDFBackground: Motor practice is an important component of neurorehabilitation. Imaging studies in healthy individuals show that dynamic brain activation changes with practice. Defining patterns of functional brain plasticity associated with motor practice following stroke could guide rehabilitation.
View Article and Find Full Text PDFTranscranial direct current stimulation (tDCS) modulates cortical excitability and is being used for human studies more frequently. Here we probe the underlying neuronal mechanisms by measuring polarity-specific changes in neurotransmitter concentrations using magnetic resonance spectroscopy (MRS). MRS provides evidence that excitatory (anodal) tDCS causes locally reduced GABA while inhibitory (cathodal) stimulation causes reduced glutamatergic neuronal activity with a highly correlated reduction in GABA, presumably due to the close biochemical relationship between the two neurotransmitters.
View Article and Find Full Text PDFNeuroimaging experiments have identified several brain regions that appear to play roles in motor learning. Here we apply a novel multivariate analytical approach to explore the dynamic interactions of brain activation regions as spatio-temporally coherent functional networks. We acquired BOLD fMRI signal during explicit motor sequence learning task to characterize the adaptive functional changes in the early phase of motor learning.
View Article and Find Full Text PDFThe aim of our study was to provide electrophysiological evidence about the modulation of the categorization process by task requirements in the human brain. Event-related potentials (ERP) were recorded during three different categorization tasks using matched stimulus sets. In all cases, the subjects were required to differentiate between "animal" and "non-animal" stimuli.
View Article and Find Full Text PDFMovement representations within the human primary motor and somatosensory cortices can be altered by motor learning. Decreases in local GABA concentration and its release may facilitate this plasticity. Here we use in vivo magnetic resonance spectroscopy (MRS) to noninvasively measure serial changes in GABA concentration in humans in a brain region including the primary sensorimotor cortex contralateral to the hand used for an isometric motor sequence learning task.
View Article and Find Full Text PDFImpaired neuronal energy metabolism, oxidative changes and microvascular abnormalities lead to altered lactate levels in Alzheimer's dementia. The aim of the present study was to assess whether intravenous sodium-lactate, a metabolic alternative and vasodilator that is thought to improve cognition, advances the cognitive performance of Alzheimer patients. Semantic categorization paradigm was used to present the electrophysiological correlates of natural scene categorization of Alzheimer patients before and after intravenous saline or sodium-lactate infusion.
View Article and Find Full Text PDFThe aim of this study was to induce changes of the oscillatory activity in the visual cortex of healthy human subjects by modulation of neuronal excitability using weak transcranial direct current stimulation (tDCS). tDCS is a non-invasive stimulation method which induces prolonged, polarity-dependent increases or reductions in cortical excitability. An increase in high frequency oscillatory activity in the beta and gamma frequency ranges is closely related in time to the N70 peak of the primary visual evoked potential (VEP), which is an early sensory component of visual activation.
View Article and Find Full Text PDFThe primary aim of this study was to determine the extent to which human MT+/V5, an extrastriate visual area known to mediate motion processing, is involved in visuomotor coordination. To pursue this we increased or decreased the excitability of MT+/V5, primary motor, and primary visual cortex by the application of 7 min of anodal and cathodal transcranial direct current stimulation (tDCS) in healthy human subjects while they were performing a visuomotor tracking task involving hand movements. The percentage of correct tracking movements increased specifically during and immediately after cathodal stimulation, which decreases cortical excitability, only when V5 was stimulated.
View Article and Find Full Text PDFPerformance of visuo-motor tasks requires the transfer of visual data to motor performance and depends highly on visual perception and cognitive processing, mainly during the learning phase. The primary aim of this study was to determine if the human middle temporal (MT)+/V5, an extrastriate visual area that is known to mediate motion processing, and the primary motor cortex are involved in learning of visuo-motor coordination tasks. To pursue this, we increased or decreased MT+/V5, primary contralateral motor (M1) and primary visual cortex excitability by 10 min of anodal or cathodal transcranial direct current stimulation in healthy human subjects during the learning phase of a visually guided tracking task.
View Article and Find Full Text PDFThe aim of this study was to investigate the temporal stability of moving phosphenes and to assess whether moving phosphene thresholds (PTs) correlate with motor thresholds (MTs). Small moving sensations, so-called moving phosphenes, are perceived when V5, an area important for visual motion analysis, is stimulated by transcranial magnetic stimulation (TMS). However, it is still a matter of debate if V5 phosphenes are stable sensations across measurements and if they are a reasonable index of the cortical excitability of V5.
View Article and Find Full Text PDFPurpose: Transcranial direct current stimulation (tDCS) has been shown to modify the perception threshold of phosphenes elicited by transcranial magnetic stimulation (TMS). The current study was undertaken to examine whether tDCS, when applied over the occipital cortex, is also able to affect visual-evoked potentials (VEPs), which characterize occipital activation in response to visual stimulation, in a polarity-specific way.
Method: For this purpose, VEPs evoked by sinusoidal luminance grating in an on/off mode were recorded before, immediately after, and 10, 20, and 30 minutes after the end of 5, 10, or 15 minutes of anodal or cathodal tDCS of the primary visual cortex.
The aim of our study was to test if the electrical stimulation of the prefrontal cortex (PFC) could modify probabilistic classification learning (PCL). Transcranial direct current stimulation (tDCS) was administered to the left prefrontal and to the primary visual cortex of 22 healthy subjects while they performed a PCL task. In this task subjects learned which of two outcomes would occur on each trial after presentation of a particular combination of cues.
View Article and Find Full Text PDFSmall moving sensations, so-called moving phosphenes are perceived, when V5, a visual area important for visual motion analysis, is stimulated by transcranial magnetic stimulation (TMS). However, it is still a matter of debate if only V5 takes part in movement perception or other visual areas are also involved in this process. In this study we tested the involvement of V1 in the perception of moving phosphenes by applying transcranial direct current stimulation (tDCS) to this area.
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