Vesna Vuksanovic

Swansea University | SWAN · College of Medicine

Functional MRI (fMRI) of ongoing brain activity at rest i.e. without any overt-directed behavior has revealed patterns of coherent activity, so called resting-state functional networks. The dynamical organization of nodes into these functional networks is closely related to the underlying structural connections. However, functional correlations hav...

Models of the human brain as a complex network of inter-connected sub-units are important in helping to understand the structural basis of the clinical features of neurodegenerative disorders. The aim of this study was to characterize in a systematic manner the differences in the structural correlation networks in cortical thickness (CT) and surfac...

Previous investigations on arithmetic stress with verbalization showed that spectral measures of heart rate variability (HRV) did not assess changes in autonomic modulation, although the heart rate (HR) increased. In this study non-linear measures of HRV are determined and linear measures are re-examined in order to understand this apparent discrep...

1 Abstract This study aims to investigate topological organization of cortical thickness and functional networks by cortical lobes. First, I demonstrated modular organization of these networks by the cortical surface frontal, temporal, parietal and occipital divisions. Secondly , I mapped the overlapping edges of cortical thickness and functional n...

1 Abstract The highly complex architecture of brain networks has been characterised by modular structures at different levels of its organisation. Here, the focus is on modular properties of brain networks from in vivo neuroimaging of cortical morphology (e.g., thickness, surface area) and activity (function). In this chapter I review findings on m...

Genetic associations with macroscopic brain networks can provide insights into healthy and aberrant cortical connectivity in disease. However, associations specific to dynamic functional connectivity in Alzheimer's disease are still largely unexplored. Understanding the association between gene expression in the brain and functional networks may pr...

Genetic associations with macroscopic brain networks can provide insights into healthy and aberrant cortical connectivity in disease. However, associations specific to dynamic functional connectivity in Alzheimer's disease are still largely unexplored. Understanding the association between gene expression in the brain and functional connectivity ma...

Background Brain hubs are highly connected regions important for integrating cognitive processing in the healthy brain. Brain hubs also play role in neurodegeneration causing dementia. However, it is not clear what brain morphometry is most useful in identifying brain regions critical to their involvement in neurodegeneration. Method We examined b...

Background Brain network analysis from resting‐state functional MRI (fMRI) has helped us to understand cortical activity in dementia. Likewise, dynamic brain networks' analysis, which takes into account temporal fluctuations in the resting‐state fMRI signal, has helped to reveal patterns of activity, usually averaged out by the conventional functio...

Background: The cerebral cortex is represented through multiple multilayer morphometric similarity networks to study their modular structures. The approach introduces a novel way for studying brain networks' metrics across individuals, and can quantify network properties usually not revealed using conventional network analyses. Methods: A total...

Background The Nucleus Basalis of Meynert (NB), located within the basal forebrain sublenticular region, is a cholinergic center with neurons providing cholinergic afferents to the entire neocortex. As posterior NB provides cholinergic innervation to the temporal pole and superior temporal cortex, this correlates well with memory loss and language...

The behavioural variant of frontotemporal dementia is a clinical syndrome characterised by changes in behaviour, cognition and functional ability. Although atrophy in frontal and temporal regions would appear to be a defining feature, neuroimaging studies have identified volumetric differences distributed across large parts of the cortex, giving ri...

This book, based on a selection of invited presentations from a topical workshop, focusses on time-variable oscillations and their interactions. The problem is challenging, because the origin of the time variability is usually unknown. In mathematical terms, the oscillations are nonautonomous, reflecting the physics of open systems where the functi...

Vuksanović, VesnaThe highly complex architecture of brain networksBrain network has been characterised by modular structures at different levels of its organisation. Here, the focus is on modular properties of brain networksBrain network from in vivo neuroimaging of cortical morphology (e.g., thickness, surface area) and activity (function). In thi...

A growing interest in complex networks theory results in an ongoing demand for new analytical tools. We propose a novel quantity based on information theory that provides a new perspective for a better understanding of networked systems: Termed ”information parity”, it quantifies the consonance of influence among nodes with respect to the whole net...

Background Reduced cortical structural properties are recognised as potential imaging marker for neurodegenerative disorders. However, networks of correlated fluctuations in cortical structural properties in Alzheimer’s disease (AD) and behavioural variant frontotemporal dementia (bvFTD) have remained elusive. Here, we set out to investigate organi...

Understanding the relationship between structural and functional organization represents one of the most important challenges in neuroscience. An increasing amount of studies show that this organization can be better understood by considering the brain as an interactive complex network. This approach has inspired a large number of computational mod...

Objective: To digitalise von Economo and Koskinas (1925) brain atlas and obtain values for layer width, cell count, neuron size from each cortical lobe. Background: Morphological differences in the cortex made it possible to map out cortical cytoarchitecture (e.g., properties of cortical layers). The differentiation of cortical cytoarchitectonic fi...

Background: Hydromethylthionine is a potent inhibitor of pathological aggregation of tau and TDP-43 proteins. Objective: To compare hydromethylthionine treatment effects at two doses and to determine how drug exposure is related to treatment response in bvFTD. Methods: We undertook a 52-week Phase III study in 220 bvFTD patients randomized to...

This study aims to investigate topological organization of cortical thickness and functional networks by cortical lobes. First, I demonstrated modular organization of these networks by the cortical surface frontal, temporal, parietal and occipital divisions. Secondly, I mapped the overlapping edges of cortical thickness and functional networks for...

Background: Although hydromethylthionine is a potent tau aggregation inhibitor, no difference was found in either of two Phase III trials in mild to moderate Alzheimer's disease (AD) comparing doses in the range 150-250 mg/day with 8 mg/day intended as a control. Objective: To determine how drug exposure is related to treatment response. Method...

A growing interest in complex networks theory results in an ongoing demand for new analytical tools. We propose a novel measure based on information theory that provides a new perspective for a better understanding of networked systems: Termed "information parity," it quantifies the consonance of influence among nodes with respect to the whole netw...

This study aims to investigate topological organization of cortical thickness and functional networks by cortical lobes. First, I demonstrated modular organization of these networks by the cortical surface frontal, temporal, parietal and occipital divisions. Secondly, I mapped the overlapping edges of cortical thickness and functional networks for...

In this short communication I present a study on cortical thickness and functional networks' coupling topology by cortical lobes. First, I demonstrated modular organisation of these networks by the cortical surface frontal, temporal, parietal and occipital divisions. Secondly, I mapped the coupling topology of cortical thickness and functional netw...

Background: LMTM is being developed as a treatment for AD based on inhibition of tau aggregation. Objectives: To examine the efficacy of LMTM as monotherapy in non-randomized cohort analyses as modified primary outcomes in an 18-month Phase III trial in mild AD. Methods: Mild AD patients (n = 800) were randomly assigned to 100 mg twice a day o...

This study combines modeling of neuronal activity and networks derived from neuroimaging data in order to investigate how the structural organization of the human brain affects the temporal dynamics of interacting brain areas. The dynamics of the neuronal activity is modeled with FitzHugh–Nagumo oscillators and the blood-oxygen-level-dependent (BOL...

This study combines experimental and modeling approaches in order to investigate the temporal dynamics of the human brain at rest. The dynamics of the neuronal activity is modeled with FitzHugh-Nagumo oscillators and the blood-oxygen-level-dependent (BOLD) time series is inferred via the Balloon-Windkessel hemodynamic model. The simulations are bas...

This study combines experimental and modeling approaches in order to investigate the temporal dynamics of the human brain at rest. The dynamics of the neuronal activity is modeled with FitzHugh-Nagumo oscillators and the blood-oxygen-level-dependent (BOLD) time series is inferred via the Balloon-Windkessel hemodynamic model. The simulations are bas...

Brain imaging methods allow a non-invasive assessment of both structural and functional connectivity. However, the mechanism of how functional connectivity arises in a structured network of interacting neural populations is as yet poorly understood. Here we use a modeling approach to explore the way in which functional correlations arise from under...

Experimental fMRI studies have shown that spontaneous brain activity i.e. in the absence of any external input, exhibit complex spatial and temporal patterns of co-activity between segregated brain regions. These so-called large-scale resting-state functional connectivity networks represent dynamically organized neural assemblies interacting with e...

To investigate the role of lateral interactions, we quantified spontaneous contractions of whole and longitudinally cut rat´s portal vein in vitro. The disruption of the wall had no effect on basic frequency determined from spectra and complexity index (CI) calculated by multiscale entropy analysis. Endothelium was disrupted and nonfunctional in al...

Well organized spatio-temporal low-frequency fluctuations (< 0.1 Hz), observed in blood-oxygen-level-dependent (BOLD) signal during rest, have been used to map several consistent resting state networks (RSNs) in the brain [1-3]. It has been hypothesized that these correlated fluctuations reflect synchronized variations in neural activity of particu...

We investigate the influence of indirect connections, interregional distance and collective effects on the large-scale functional networks of the human cortex. We study topologies of empirically derived resting state networks (RSNs), extracted from fMRI data, and model dynamics on the obtained networks. The RSNs are calculated from mean time-series...

Spatio-temporally organized low-frequency fluctuations (<0.1 Hz) of blood-oxygen-level-dependent (BOLD) fMRI signal have been intensively investigated as a measure of functional connectivity (FC) between region pairs in the whole brain [1]. Resting state FC is commonly assumed to be shaped by the underlying anatomical connectivity (AC). Furthermore...

The functional magnetic resonance imaging (fMRI) blood oxygenation level-dependent (BOLD) signal is regularly used to assign neuronal activity to cognitive function. Recent analyses have shown that the local field potential (LFP) gamma power is a better predictor of the fMRI BOLD signal than spiking activity. However, LFP gamma power and spiking ac...

We apply wavelet-based time-localized phase coherence to investigate the relationship between blood flow and skin temperature, and between blood flow and instantaneous heart rate (IHR), during vasoconstriction and vasodilation provoked by local cooling or heating of the skin. A temperature-controlled metal plate (approximately 10 cm2) placed on the...

We studied nonlinear dynamics underlying spontaneous rhythmical contractions of isolated rat portal vein. The signals were acquired at four different temperatures important in isolated blood vessels preparations: 4, 22, 37 and 40 degrees C. To characterize the system's nonlinearity, we calculated the largest Lyapunov exponent, sample entropy and sc...

We present a study of the relationship between blood flow and skin temperature under different dynamics of skin-temperature-change: locally induced thermal shock and well controlled, gradual change. First, we demonstrate memory phenomena for blood flow and skin temperature under both conditions. Secondly, we point out that the "hysteresis" loops ob...

Introduction. Spectral analysis of heart rhythm variability is a noninvasive method to study cardiovascular autonomic control. Nonlinear methods of analysis of heart rhythm variability may provide an additional information on properties of RR interval dynamics, which cannot be revealed by linear methods. The aim of this study was to investigate and...

In this study we investigated nonlinear and linear characteristics of heart period variability with aging in supine and standing posture. Sixty healthy subjects (8-61 years) divided in three age groups participated in the study. Heart period variability was assessed by measurement of short-term scaling exponent, sample entropy, largest Lyapunov exp...

Nonlinear measures of heart period variability (HPV) were determined in supine rest and standing posture in children and young adults with heart disease and compared to the control. The aim was to study influence of posture and heart disease on heart period dynamics. It was found that standing increases short-term scaling exponent in all subjects a...

Reduction of heart rate variability as a consequence of heart disease and postural change has been well documented. However, the data on the effect of postural change in pediatric patients are incomplete and the effect is not fully understood. The aim of the study was to investigate effect of postural change on heart rate variability in relation to...