Cortical Mechanisms of Human Pelvic Floor Muscle Synergies

The human pelvic floor is an anatomically, functionally, and morphologically complex region that is associated with many disorders such as chronic prostatitis/pelvic pain syndrome (CPPS), chronic low back pain, and urinary incontinence. The purpose of this dissertation was to explore the cortical mechanisms that underlie human pelvic floor muscle synergies. Our first original experiment involved the study of 20 healthy male controls who were instructed to perform a variety of muscle tasks presumed to be associated with pelvic floor muscle synergies. Surface electromyography (EMG) method was used to detect timing onsets, as well as activation patterns of the pelvic floor, gluteus maximus, and first dorsal interosseous muscles. Functional magnetic resonance imaging (fMRI) was used to measure blood oxygenation density levels (BOLD) in the brain while subjects performed various prime mover tasks. Our second original experiment involved another set of 10 healthy male subjects who were trained to perform a complex synergy breaking/decoupling task that was confirmed with EMG. They repeated the coupling motor task (gluteal activation) as well as the more complex motor decoupling task while being scanned with fMRI, so that BOLD signals could be compared. The first experiment revealed evidence of cortically facilitated synergy of the pelvic floor muscles and the second experiment revealed that complex motor tasks such as the breaking of a cortically facilitated muscle synergy involves BOLD signals in the brain known to be involved with interoception

Changes in the Brain Microstructure of Children with Primary Monosymptomatic Nocturnal Enuresis: A Diffusion Tensor Imaging Study

Background: Primary monosymptomatic nocturnal enuresis (PMNE) is a common disorder in school-aged children. Previous studies have suggested that a developmental delay might play a role in the pathology of children with PMNE. However, microstructural abnormalities in the brains of these children have not been thoroughly investigated. Methodology/Principal Findings: In this work, we evaluated structural changes in the brains of children with PMNE using diffusion tensor imaging (DTI). Two groups consisting of 26 children with PMNE and 26 healthy controls were scanned using magnetic resonance DTI. The diffusion parameters of fractional anisotropy (FA) and mean diffusivity (MD) were subjected to whole-brain, voxel-wise group comparisons using statistical parametric mapping (SPM). When compared to healthy subjects, children with PMNE showed both a decrease in FA and an increase in MD in the thalamus. MD also increased in the frontal lobe, the anterior cingulate cortex and the insula; these areas are all involved in controlling micturition. The significant changes seen in the thalamus could affect both urine storage and arousal from sleep. Conclusions/Significance: The microstructure abnormalities were observed in the thalamus, the medial frontal gyrus, the anterior cingulate cortex and the insula, which are involved in micturition control network. This indicates developmenta

A systematic review and activation likelihood estimation meta-Analysis of the central innervation of the lower urinary tract: Pelvic floor motor control and micturition

Purpose Functional neuroimaging is a powerful and versatile tool to investigate central lower urinary tract (LUT) control. Despite the increasing body of literature there is a lack of comprehensive overviews on LUT control. Thus, we aimed to execute a coordinate based meta-Analysis of all PET and fMRI evidence on descending central LUT control, i.e. pelvic floor muscle contraction (PFMC) and micturition. Materials and methods A systematic literature search of all relevant libraries was performed in August 2020. Coordinates of activity were extracted from eligible studies to perform an activation likelihood estimation (ALE) using a threshold of uncorrected p 0.001. Results 20 of 6858 identified studies, published between 1997 and 2020, were included. Twelve studies investigated PFMC (1xPET, 11xfMRI) and eight micturition (3xPET, 5xfMRI). The PFMC ALE analysis (n = 181, 133 foci) showed clusters in the primary motor cortex, supplementary motor cortex, cingulate gyrus, frontal gyrus, thalamus, supramarginal gyrus, and cerebellum. The micturition ALE analysis (n = 107, 98 foci) showed active clusters in the dorsal pons, including the pontine micturition center, the periaqueductal gray, cingulate gyrus, frontal gyrus, insula and ventral pons. Overlap of PFMC and micturition was found in the cingulate gyrus and thalamus. Conclusions For the first time the involved core brain areas of LUT motor control were determined using ALE. Furthermore, the involved brain areas for PFMC and micturition are partially distinct. Further neuroimaging studies are required to extend this ALE analysis and determine the differences between a healthy and a dysfunctional LUT. This requires standardization of protocols and task-execution

Bladder Dysfunction in the Context of the Bladder-Brain Connection

The aim of the thesis "Bladder dysfunction in the context of the bladder-brain connection" written by Ilse Groenendijk, was to investigate potential diagnostic tools in the field of functional urology. The first aim was to define the brain areas involved in LUT control in healthy individuals and to investigate the clinical applicability of dynamic brain imaging as a diagnostic tool of functional bladder disorders in individuals. The second aim was to evaluate and improve traditional and patient reported outcome measurements in the field of functional urology

The Neurobiology of Human Vocalization: A Quantitative Meta-Analytic Approach

Vocalization is critical to communication and understanding the neural mechanisms that control voice is a critical scientific and clinical endeavor. Studies have used a variety of neuroimaging techniques to investigate the neural correlates of vocal control using perturbation tasks. These studies have provided substantial evidence that there is a critical role of the Superior Temporal Gyrus (STG) in error detection/correction during vocalization. The STG appears to function as a regulatory region within a complex network of brain areas that control human vocalization. The aims of this study were to 1) Use Activation Likelihood Estimation (ALE) analyses to substantiate the neural regions activation during vocalization; 2) To determine the functional significance of the neural regions activated during vocalization, as characterized by the BrainMap database; 3) To parcellate the bilateral STG by means of Connectivity Based Parcellation (CBP) and functionally characterize any discreate subregions found. Results of the vocalization ALE analysis revealed activation of the bilateral STG, right supplementary motor area, bilateral precentral gyrus, right inferior frontal gyrus, right pallidum, left putamen and right cerebellum (VI), which largely substantiates previous findings of the vocalization network. Results of CBP revealed six distinct subregions of the left and right STG, with major functional characterization in the domains of perception, action, and cognition and in the specific tasks of music production and stimulus monitoring/discrimination

Investigating white matter changes underlying overactive bladder in multiple sclerosis with diffusion MRI

Lower urinary tract symptoms (LUTS) are presented in more than 80% of multiple sclerosis (MS) patients. Current understanding of LUT control is based on studies exploring activities in grey matter (GM) and investigating functional correlations with LUTS. The relationship between white matter (WM) changes and overactive bladder (OAB) symptoms are limited to findings in small vessel disease, and the nature of the association between WM changes and OAB symptoms is poorly understood. Advanced diffusion-weighted magnetic resonance imaging (MRI) techniques provide non-invasive techniques to study WM abnormalities and correlates to clinical observations. The overarching objectives of this work are to explore WM abnormalities subtending OAB symptoms in MS, and to reconstruct the structural network underpinning the working model of lower urinary tract (LUT) control. Using Tract-Based Spatial Statistics (TBSS), OAB symptoms related WM abnormalities in MS can be identified, and a structural network subtending OAB symptoms in MS can be subsequently created. The findings of this work illustrate the correlation between OAB symptoms severity and WM abnormalities in MS. These were observed in regions in frontal lobes and non-dominant hemisphere, including corpus callosum, anterior corona radiata bilaterally, right anterior thalamic radiation, superior longitudinal fasciculus bilaterally, and right inferior longitudinal fasciculus. The structural network created for OAB symptoms in MS connected regions known to be involved in the working model of LUT control, and the network identified connectivity between insula and frontal lobe, which is the key circuit for perception of bladder fullness. Moreover, structural connectivity between insula-temporal lobe and insula-occipital lobe were observed, which may underpin changes seen in functional MRI (fMRI) studies. The novel findings of this study present WM abnormalities and structural connectivity subtending LUTS in MS with diffusion-weighted imaging (DWI). The techniques used in this work can be applied to other patterns of LUTS and other neurological diseases

Premonitory urges are associated with decreased grey matter thickness within the insula and sensorimotor cortex in young people with Tourette syndrome

Tourette syndrome (TS) is a neurological disorder characterized by vocal and motor tics and is associated with cortical–striatal–thalamic–cortical circuit (CSTC) dysfunction and hyperexcitability of cortical limbic and motor regions, which are thought to lead to the occurrence of tics. Importantly, individuals with TS often report that their tics are preceded by ‘premonitory sensory phenomena’ (PSP) that are described as uncomfortable cognitive or bodily sensations that precede the execution of a tic, and are experienced as a strong urge for motor discharge. While the precise role played by PSP in the occurrence of tics is controversial, PSP are nonetheless of considerable theoretical and clinical importance in TS, not least because they form the core component in many of the behavioural therapies that are currently used in the treatment of tic disorders. In this study, we investigated the brain structure correlates of PSP. Specifically, we conducted a whole-brain analysis of cortical (grey matter) thickness in 29 children and young adults with TS and investigated the association between grey matter thickness and PSP. We demonstrate for the first time that PSP are inversely associated with grey matter thickness measurements within the insula and sensori-motor cortex. We also demonstrate that grey matter thickness is significantly reduced in these areas in individuals with TS relative to a closely age- and gender-matched group of typically developing individuals and that PSP ratings are significantly correlated with tic severity

Premonitory urges are associated with decreased grey matter thickness within the insula and sensorimotor cortex in young people with Tourette syndrome

Tourette syndrome (TS) is a neurological disorder characterized by vocal and motor tics and is associated with cortical–striatal–thalamic–cortical circuit (CSTC) dysfunction and hyperexcitability of cortical limbic and motor regions, which are thought to lead to the occurrence of tics. Importantly, individuals with TS often report that their tics are preceded by ‘premonitory sensory phenomena’ (PSP) that are described as uncomfortable cognitive or bodily sensations that precede the execution of a tic, and are experienced as a strong urge for motor discharge. While the precise role played by PSP in the occurrence of tics is controversial, PSP are nonetheless of considerable theoretical and clinical importance in TS, not least because they form the core component in many of the behavioural therapies that are currently used in the treatment of tic disorders. In this study, we investigated the brain structure correlates of PSP. Specifically, we conducted a whole-brain analysis of cortical (grey matter) thickness in 29 children and young adults with TS and investigated the association between grey matter thickness and PSP. We demonstrate for the first time that PSP are inversely associated with grey matter thickness measurements within the insula and sensori-motor cortex. We also demonstrate that grey matter thickness is significantly reduced in these areas in individuals with TS relative to a closely age- and gender-matched group of typically developing individuals and that PSP ratings are significantly correlated with tic severity