Vivek Prabhakaran

Vivek Prabhakaran
University of Wisconsin–Madison | UW · Department of Radiology

MD,PhD

About

247
Publications
31,152
Reads
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9,236
Citations
Citations since 2017
113 Research Items
4317 Citations
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20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
Additional affiliations
June 2001 - June 2008
Johns Hopkins University
Position
  • Resident-Fellow

Publications

Publications (247)
Article
Brain-computer interface (BCI)-mediated functional electrical stimulation (FES) of stroke impaired upper extremity motor function has been shown to improve motor capacity but accurate dosing of BCI-FES has not been determined. This analysis seeks to determine whether participants with a greater number of FES runs realized greater change in the Stro...
Article
Full-text available
There has been increasing recognition for the decline of motor function in Alzheimer’s disease (AD) progression and its substantial role in disease morbidity. However, less is known about regional pathology burden—including amyloid‐β and tau protein deposition and cortical trophy—and its relationship to motor performance. Here investigate this rela...
Article
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Brain myelin is known to play an important role in maintaining optimal neuronal function, with deficits in myelin leading to worse performance on cognitive tests. The extent to which cortex‐specific myelin is associated with other cognitive domains, or is impacted by disease processes such as Alzheimer’s disease (AD), is unknown. Here we leverage M...
Article
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We propose a unique, minimal assumption, approach based on variance analyses (compared with standard approaches) to investigate genetic influence on individual differences on the functional connectivity of the brain using 65 monozygotic and 65 dizygotic healthy young adult twin pairs' low‐frequency oscillation resting state fMRI data from the Human...
Chapter
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Chapter
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13 Imaging of Alzheimer's disease: Part 1
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Background: Structural and functional integrity of blood vessels and adequate supply of blood are essential to normal brain functioning. In addition, cerebral blood flow shortfalls and blood-brain barrier (BBB) dysfunction are increasingly recognized to contribute to Alzheimer's disease (AD) pathophysiology. Methods: Our advanced magnetic resonance...
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PET and fMRI studies suggest that auditory narrative comprehension is supported by a bilateral multilobar cortical network. The superior temporal resolution of magnetoencephalography (MEG) makes it an attractive tool to investigate the dynamics of how different neuroanatomic substrates engage during narrative comprehension. Using beta-band power ch...
Article
Background Ischaemic brain infarction can occur without acute neurological symptoms (covert strokes) or with symptoms (overt strokes), both associated with poor health outcomes. We conducted a pilot study of the incidence of preoperative and postoperative (intraoperative or postoperative) covert strokes, and explored the relationship of postoperati...
Article
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Machine learning analyses were performed on graph theory (GT) metrics extracted from brain functional and morphological data from temporal lobe epilepsy (TLE) patients in order to identify intrinsic network phenotypes and characterize their clinical significance. Participants were 97 TLE and 36 healthy controls from the Epilepsy Connectome Project....
Article
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Limitations in the accuracy of brain pathways reconstructed by diffusion MRI (dMRI) tractography have received considerable attention. While the technical advances spearheaded by the Human Connectome Project (HCP) led to significant improvements in dMRI data quality, it remains unclear how these data should be analyzed to maximize tractography accu...
Article
Full-text available
Background and purpose: Traumatic brain injury (TBI) can lead to movement and balance deficits. In addition to physical therapy, brain-based neurorehabilitation efforts have begun to show promise in improving these deficits. The present study investigated the effectiveness of translingual neural stimulation (TLNS) on patients with mild-to-moderate...
Article
Full-text available
An increasing number of research teams are investigating the efficacy of brain-computer interface (BCI)-mediated interventions for promoting motor recovery following stroke. A growing body of evidence suggests that of the various BCI designs, most effective are those that deliver functional electrical stimulation (FES) of upper extremity (UE) muscl...
Article
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Objectives: Central nervous system effects of lingual strengthening exercise to treat dysphagia remain largely unknown. This pilot study measured changes in microstructural white matter to capture alterations in neural signal processing following lingual strengthening exercise. Methods: Diffusion-weighted images were acquired from seven particip...
Article
Full-text available
Introduction: Non-invasive electroencephalographic (EEG) based brain-computer interface (BCI) therapy has been shown to increase upper extremity mobility in stroke survivors with persistent upper extremity motor impairment. Previous studies have shown that in order to evoke movement from a particular motor system, sensory cues are combined in an es...
Preprint
Full-text available
Limitations in the accuracy of brain pathways reconstructed by diffusion MRI (dMRI) tractography have received considerable attention. While the technical advances spearheaded by the Human Connectome Project (HCP) led to significant improvements in dMRI data quality, it remains unclear how these data should be analyzed to maximize tractography accu...
Article
Full-text available
Overall age of an individual is commonly measured in chronological time. With the advent of in vivo imaging and reliable predictive modeling, a finer gradation of the age into many internal biological scales such as cellular, tissue, organ and cognitive aging etc. can be estimated. Accurate estimation of the age of the in vivo brain can offer insig...
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Prior studies employing neuromelanin‐sensitive MRI have linked neurodegeneration in the locus coeruleus (LC) to Alzheimer’s disease (AD) pathology. MPnRAGE (Keckskemeti et al., 2016), a novel MRI technique developed at UW‐Madison, generates multiple inversion recovery contrasts and quantitative T1 relaxometry. Quantitative R1 (= 1/T1), the longitud...
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Autosomal dominant Alzheimer’s disease (AD) is caused by known genetic mutations which results in the biochemical consequences that underlie the pathological basis of the disease, and a disease process driven by amyloid accumulation. Mutation carriage is characterized by substantial amyloid accumulation, and dementia onset at or around the age of p...
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Alzheimer’s disease dementia (AD) and mild cognitive impairment (MCI) are characterized by degeneration of myelinated axonal fiber bundles which subserve network connectivity, and degeneration of which ultimately leads to the dementia syndrome. Most of the prior disease related findings derived from diffusion weighted magnetic resonance imaging (dM...
Article
Full-text available
White matter bundle segmentation using diffusion MRI fiber tractography has become the method of choice to identify white matter fiber pathways in vivo in human brains. However, like other analyses of complex data, there is considerable variability in segmentation protocols and techniques. This can result in different reconstructions of the same in...
Article
Full-text available
Throughout adulthood, the brain undergoes an array of structural and functional changes during the typical aging process. These changes involve decreased brain volume, reduced synaptic density, and alterations in white matter (WM). Although there have been some previous neuroimaging studies that have measured the ability of adult language productio...
Article
Full-text available
Stroke is a leading cause of acquired long-term upper extremity motor disability. Current standard of care trajectories fail to deliver sufficient motor rehabilitation to stroke survivors. Recent research suggests that use of brain-computer interface (BCI) devices improves motor function in stroke survivors, regardless of stroke severity and chroni...
Article
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Functional resonance magnetic imaging (fMRI) allows for identification of eloquent cortex in pre-treatment planning. Previous studies have shown a correlation among lesion to activation distance (LAD) measures and morbidity and mortality. This study investigates the relationship between LAD, well-established language centers (Wernicke’s and Broca’s...
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While most survivors of stroke experience some spontaneous recovery and receive treatment in the subacute setting, they are often left with persistent impairments in upper limb sensorimotor function which impact autonomy in daily life. Brain-Computer Interface (BCI) technology has shown promise as a form of rehabilitation that can facilitate motor...
Article
Full-text available
White matter bundle segmentation using diffusion MRI fiber tractography has become the method of choice to identify white matter fiber pathways in vivo in human brains. However, like other analyses of complex data, there is considerable variability in segmentation protocols and techniques. This can result in different reconstructions of the same in...
Article
Full-text available
Musicians with absolute pitch ability show better spatial ability, but little is known about whether non-musicians’ pitch identification (PI) ability is associated with their spatial ability. In the present study, a PI test, two mental rotation (MR) tests (Three-Dimensional Mental Rotation [3DMR] and Spatial Relationship [SR]), and eight executive...
Article
Temporal lobe epilepsy (TLE) has been conceptualized as focal disease with a discrete neurobiological focus and can respond well to targeted resection or ablation. In contrast, the neuro-cognitive deficits resulting from TLE can be widespread involving regions beyond the primary epileptic network. We hypothesize that this seemingly paradoxical find...
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Background It is unclear how preoperative neurodegeneration and postoperative changes in EEG delta power relate to postoperative delirium severity. We sought to understand the relative relationships between neurodegeneration and delta power as predictors of delirium severity. Methods We undertook a prospective cohort study of high-risk surgical pa...
Article
Purpose The neuropsychological complications of temporal lobe epilepsy are characterized by a spectrum of reproducible cognitive phenotypes that vary in the presence, type and degree of impairment. The nature of the disruptions to the neuropsychological networks that underlie these phenotypes remain to be characterized and represent the subject of...
Article
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Objective: This study is part of a clinical trial designed to test the efficacy of an EEG-based BCI intervention for upper extremity motor rehabilitation in stroke survivors. The analyses presented here focus on the effectiveness of BCI intervention as a function of somatosensory integrity. Introduction: Human motor control requires integration of...
Preprint
Full-text available
Determining genetic versus environmental influences on the human brain is of crucial importance to understand the healthy brain as well as in a variety of disease and disorder states. Here we propose a unique, minimal assumption, approach to investigate genetic influence on the functional connectivity of the brain using 260 subjects” (65 monozygoti...
Article
Full-text available
The intracarotid sodium amobarbital procedure (ISAP or Wada test) lateralizes cerebral functions to the cerebral hemispheres preoperatively. Functional magnetic resonance imaging (fMRI) is increasingly used to characterize preoperative language and memory lateralization. In this study, concordance of fMRI with Wada was examined in patients with med...
Article
Full-text available
White matter bundle segmentation using diffusion MRI fiber tractography has become the method of choice to identify white matter fiber pathways in vivo in human brains. However, like other analyses of complex data, there is considerable variability in segmentation protocols and techniques. This can result in different reconstructions of the same in...
Article
Full-text available
Neural networks derived from diffusion‐weighted MRI (DW‐MRI) may shed light on disease progression and pathology propagation in Alzheimer’s disease in vivo. In this work analysis of the path properties of such networks are presented. Geodesic or shortest paths are fundamental in understanding key network phenomenon such as the propagation rates of...
Article
Full-text available
Congenital Zika virus (ZIKV) exposure results in a spectrum of disease ranging from severe birth defects to delayed onset neurodevelopmental deficits. ZIKV-related neuropathogenesis, predictors of birth defects, and neurodevelopmental deficits are not well defined in people. Here we assess the methodological and statistical feasibility of a congeni...
Preprint
Full-text available
White matter bundle segmentation using diffusion MRI fiber tractography has become the method of choice to identify white matter fiber pathways in vivo in human brains. However, like other analyses of complex data, there is considerable variability in segmentation protocols and techniques. This can result in different reconstructions of the same in...
Article
Neuroticism, a core personality trait characterized by a tendency towards experiencing negative affect, has been reported to be higher in people with temporal lobe epilepsy (TLE) compared with healthy individuals. Neuroticism is a known predictor of depression and anxiety, which also occur more frequently in people with TLE. The purpose of this stu...
Article
Full-text available
Traumatic brain injury (TBI) of varying severity can result in balance and movement disorders, for which the benefits of treatment with physical therapy has limits. In this study, patients with post-TBI balance issues received translingual neural stimulation (TLNS) in concert with physical therapy and the effects on the grey matter volume (GMV) wer...
Conference Paper
Full-text available
Synopsis We present results from IronTract, the first challenge to evaluate tractography on the two-shell diffusion scheme of the Human Connectome Project (HCP). Accuracy was evaluated by comparison to tracer injections in the same macaque brains as the diffusion data. Training and validation datasets involved different injection sites. We observed...
Article
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This study explored the taxonomy of cognitive impairment within temporal lobe epilepsy and characterized the sociodemographic, clinical and neurobiological correlates of identified cognitive phenotypes. 111 temporal lobe epilepsy patients and 83 controls (mean ages 33 and 39, 57% and 61% female, respectively) from the Epilepsy Connectome Project un...
Article
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Background Delirium frequently affects older patients, increasing morbidity and mortality; however, the pathogenesis is poorly understood. Herein, we tested the cognitive disintegration model, which proposes that a breakdown in frontoparietal connectivity, provoked by increased slow-wave activity (SWA), causes delirium. Methods We recruited 70 sur...
Article
Full-text available
Objectives Translingual neurostimulation (TLNS) studies indicate improved outcomes in neurodegenerative disease or spinal cord injury patients. This study was designed to assess the safety and efficacy of TLNS plus targeted physical therapy (PT) in people with a chronic balance deficit after mild‐to‐moderate traumatic brain injury (mmTBI). Materia...
Conference Paper
Multiple magnetic resonance imaging (MRI) modalities are currently used for the diagnosis and characterization of temporal lobe epilepsy (TLE). The objective of this study is to assess the performance of individual and combination of multimodal MRI datasets to provide an accurate classification of TLE by employing a multi-channel deep neural networ...
Article
Full-text available
Patients with inflammatory bowel disease have been shown to have abnormal brain morphometry or function, which are associated with psychological symptoms such as stress, depression or anxiety. The present work recruited 20 Crohn’s disease patients in remission (CDs) and 20 age-gender-handedness-education matched healthy controls (HCs) and compared...
Article
Full-text available
Objective: This research seeks to identify changes in frequency specific directional flow of information transmission (functional connectivity) as a result of BCI intervention. Direct path functional connectivity (isolated effective coherence (iCOH)) changes between motor-related brain areas (Brodmann areas (BA) 1-7) are thought to relate to electr...
Article
Full-text available
This research seeks to identify source localization of neuromechanical changes associated with gains in hand grip function following BCI intervention sessions for upper extremity motor recovery. Mu rhythm desynchronization (ERD) of contralateral brain motor areas is thought to occur during movement and changes in brain motor area ERD relate to chan...
Article
Full-text available
Functional magnetic resonance imaging (fMRI)-based functional connectivity (FC) commonly characterizes the functional connections in the brain. Conventional quantification of FC by Pearson's correlation captures linear, time-domain dependencies among blood-oxygen-level-dependent (BOLD) signals. We examined measures to quantify FC by investigating:...
Article
Full-text available
Understanding how global brain networks are affected in epilepsy may elucidate the pathogenesis of seizures and its accompanying neurobehavioral comorbidities. We investigated functional changes within neural networks in temporal lobe epilepsy (TLE) using graph theory analysis of resting-state connectivity. 27 TLE presurgical patients (age 41.0 ± 1...
Article
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The association of epilepsy with structural brain changes and cognitive abnormalities in midlife has raised concern regarding the possibility of future accelerated brain and cognitive aging and increased risk of later life neurocognitive disorders. To address this issue we examined age-related processes in both structural and functional neuroimagin...
Article
While delirium is associated with cognitive decline and dementia, there is limited evidence to support causality for this relationship. Clarification of how delirium may cause cognitive decline, perhaps through evidence of contemporaneous neuronal injury, would enhance plausibility for a causal relationship. Dose-dependence of neuronal injury with...
Article
Full-text available
Background In utero Zika virus (ZIKV) infection causes birth defects and neurodevelopmental deficits in neonates. We reasoned that a translational macaque model of congenital ZIKV infection could define disease pathophysiology not possible in human clinical studies. Methods We inoculated 5 pregnant rhesus macaques with a Puerto Rican isolate of ZI...
Conference Paper
Full-text available
Positron emission tomography (PET) imaging is an imaging modality for diagnosing a number of neurological diseases. In contrast to Magnetic Resonance Imaging (MRI), PET is costly and involves injecting a radioactive substance into the patient. Motivated by developments in modality transfer in vision, we study the generation of certain types of PET...
Article
Full-text available
Behavioral and personality disorders in temporal lobe epilepsy (TLE) have been a topic of interest and controversy for decades, with less attention paid to alterations in normal personality structure and traits. In this investigation, core personality traits (the Big 5) and their neurobiological correlates in TLE were explored using the Neuroticism...
Article
Full-text available
Objective: To compare the efficacy of high- and low-frequency noninvasive translingual neurostimulation (TLNS) plus targeted physical therapy (PT) for treating chronic balance and gait deficits due to mild-to-moderate traumatic brain injury (mmTBI). Design: Participants were randomized 1:1 in a 26-week double-blind phase 1/2 study (NCT02158494)...
Preprint
Full-text available
Positron emission tomography (PET) imaging is an imaging modality for diagnosing a number of neurological diseases. In contrast to Magnetic Resonance Imaging (MRI), PET is costly and involves injecting a radioactive substance into the patient. Motivated by developments in modality transfer in vision, we study the generation of certain types of PET...
Preprint
Full-text available
Congenital Zika virus (ZIKV) exposure results in a spectrum of disease ranging from severe birth defects to delayed onset neurodevelopmental deficits. ZIKV-related neuropathogenesis, predictors of birth defects, and neurodevelopmental deficits are not well defined in people. Here we assess the methodological and statistical feasibility of a congeni...
Article
Full-text available
Cortical thickness is traditionally derived from T1-weighted MRI images. Recent studies have shown an improvement in segmentation with the combination of T1 + T2-FLAIR images. MRI data from 54 adults (mean: 71 years, 65–81 years, 48% females) that are part of an ongoing cohort study were analyzed to investigate whether T1 + T2-FLAIR cortical thickn...