scholarly journals Vagal nerve stimulation triggers widespread responses and alters large-scale functional connectivity in the rat brain

2017 ◽  
Author(s):  
Jiayue Cao ◽  
Kun-Han Lu ◽  
Terry L. Powley ◽  
Zhongming Liu
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Large Scale ◽  
Time Course ◽  
Brain Networks ◽  
Blood Oxygenation ◽  
7 Tesla ◽  
Sprague Dawley ◽  
Wide Range ◽  
Oxygenation Level

AbstractVagus nerve stimulation (VNS) is a therapy for epilepsy and depression. However, its efficacy varies and its mechanism remains unclear. Prior studies have used functional magnetic resonance imaging (fMRI) to map brain activations with VNS in human brains, but have reported inconsistent findings. The source of inconsistency is likely attributable to the complex temporal characteristics of VNS-evoked fMRI responses that cannot be fully explained by simplified response models in the conventional model-based analysis for activation mapping. To address this issue, we acquired 7-Tesla blood oxygenation level dependent fMRI data from anesthetized Sprague–Dawley rats receiving electrical stimulation at the left cervical vagus nerve. Using spatially independent component analysis, we identified 20 functional brain networks and detected the network-wise activations with VNS in a data-driven manner. Our results showed that VNS activated 15 out of 20 brain networks, and the activated regions covered >76% of the brain volume. The time course of the evoked response was complex and distinct across regions and networks. In addition, VNS altered the strengths and patterns of correlations among brain networks relative to those in the resting state. The most notable changes in network-network interactions were related to the limbic system. Together, such profound and widespread effects of VNS may underlie its unique potential for a wide range of therapeutics to relieve central or peripheral conditions.

scholarly journals Impact of Transcutaneous Auricular Vagus Nerve Stimulation on Large-Scale Functional Brain Networks: From Local to Global

2021 ◽  
Vol 12 ◽  
Author(s):  
Thorsten Rings ◽  
Randi von Wrede ◽  
Timo Bröhl ◽  
Sophia Schach ◽  
Christoph Helmstaedter ◽  
...  
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Mode Of Action ◽  
Vagus Nerve Stimulation ◽  
Large Scale ◽  
Brain Networks ◽  
Short Term ◽  
Functional Brain ◽  
Functional Brain Networks ◽  
The Impact

Transcutaneous auricular vagus nerve stimulation (taVNS) is a novel non-invasive brain stimulation technique considered as a potential supplementary treatment option for a wide range of diseases. Although first promising findings were obtained so far, the exact mode of action of taVNS is not fully understood yet. We recently developed an examination schedule to probe for immediate taVNS-induced modifications of large-scale epileptic brain networks. With this schedule, we observed short-term taVNS to have a topology-modifying, robustness- and stability-enhancing immediate effect on large-scale functional brain networks from subjects with focal epilepsies. We here expand on this study and investigate the impact of short-term taVNS on various local and global characteristics of large-scale evolving functional brain networks from a group of 30 subjects with and without central nervous system diseases. Our findings point to differential, at first glance counterintuitive, taVNS-mediated alterations of local and global topological network characteristics that result in a reconfiguration of networks and a modification of their stability and robustness properties. We propose a model of a stimulation-related stretching and compression of evolving functional brain networks that may help to better understand the mode of action of taVNS.

scholarly journals Transcutaneous auricular vagus nerve stimulation induces stabilizing modifications in large-scale functional brain networks: towards understanding the effects of taVNS in subjects with epilepsy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Randi von Wrede ◽  
Thorsten Rings ◽  
Sophia Schach ◽  
Christoph Helmstaedter ◽  
Klaus Lehnertz
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Large Scale ◽  
Brain Networks ◽  
Prospective Trial ◽  
Brain Network ◽  
Short Term ◽  
Functional Brain Networks ◽  
Network Properties

AbstractTranscutaneous auricular vagus nerve stimulation (taVNS) is a novel non-invasive brain stimulation technique considered as a potential supplementary treatment option for subjects with refractory epilepsy. Its exact mechanism of action is not yet fully understood. We developed an examination schedule to probe for immediate taVNS-induced modifications of large-scale epileptic brain networks and accompanying changes of cognition and behaviour. In this prospective trial, we applied short-term (1 h) taVNS to 14 subjects with epilepsy during a continuous 3-h EEG recording which was embedded in two standardized neuropsychological assessments. From these EEG, we derived evolving epileptic brain networks and tracked important topological, robustness, and stability properties of networks over time. In the majority of investigated subjects, taVNS induced measurable and persisting modifications in network properties that point to a more resilient epileptic brain network without negatively impacting cognition, behaviour, or mood. The stimulation was well tolerated and the usability of the device was rated good. Short-term taVNS has a topology-modifying, robustness- and stability-enhancing immediate effect on large-scale epileptic brain networks. It has no detrimental effects on cognition and behaviour. Translation into clinical practice requires further studies to detail knowledge about the exact mechanisms by which taVNS prevents or inhibits seizures.

Feasibility of Vagus Nerve Stimulation–Synchronized Blood Oxygenation Level–Dependent Functional MRI

2001 ◽  
Vol 36 (8) ◽  
pp. 470-479 ◽  
Author(s):  
DARYL E. BOHNING ◽  
MIKHAIL P. LOMAREV ◽  
STEWART DENSLOW ◽  
ZIAD NAHAS ◽  
ANANDA SHASTRI ◽  
...  
Keyword(s):  
Vagus Nerve ◽  
Functional Mri ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Blood Oxygenation Level ◽  
Oxygenation Level

scholarly journals Activity-dependent myelination: A glial mechanism of oscillatory self-organization in large-scale brain networks

2020 ◽  
Vol 117 (24) ◽  
pp. 13227-13237 ◽  
Author(s):  
Rabiya Noori ◽  
Daniel Park ◽  
John D. Griffiths ◽  
Sonya Bells ◽  
Paul W. Frankland ◽  
...  
Keyword(s):  
White Matter ◽  
Large Scale ◽  
Phase Synchronization ◽  
Brain Networks ◽  
Self Organization ◽  
Conduction Delay ◽  
Neural Communication ◽  
Wide Range ◽  
The Impact ◽  
Activity Dependent

Communication and oscillatory synchrony between distributed neural populations are believed to play a key role in multiple cognitive and neural functions. These interactions are mediated by long-range myelinated axonal fiber bundles, collectively termed as white matter. While traditionally considered to be static after development, white matter properties have been shown to change in an activity-dependent way through learning and behavior—a phenomenon known as white matter plasticity. In the central nervous system, this plasticity stems from oligodendroglia, which form myelin sheaths to regulate the conduction of nerve impulses across the brain, hence critically impacting neural communication. We here shift the focus from neural to glial contribution to brain synchronization and examine the impact of adaptive, activity-dependent changes in conduction velocity on the large-scale phase synchronization of neural oscillators. Using a network model based on primate large-scale white matter neuroanatomy, our computational and mathematical results show that such plasticity endows white matter with self-organizing properties, where conduction delay statistics are autonomously adjusted to ensure efficient neural communication. Our analysis shows that this mechanism stabilizes oscillatory neural activity across a wide range of connectivity gain and frequency bands, making phase-locked states more resilient to damage as reflected by diffuse decreases in connectivity. Critically, our work suggests that adaptive myelination may be a mechanism that enables brain networks with a means of temporal self-organization, resilience, and homeostasis.

scholarly journals Methods for Determining Frequency- and Region-Dependent Relationships Between Estimated LFPs and BOLD Responses in Humans

2009 ◽  
Vol 101 (1) ◽  
pp. 491-502 ◽  
Author(s):  
Roberto Martuzzi ◽  
Micah M. Murray ◽  
Reto A. Meuli ◽  
Jean-Philippe Thiran ◽  
Philippe P. Maeder ◽  
...  
Keyword(s):  
Human Subjects ◽  
Brain Regions ◽  
Source Model ◽  
Blood Oxygenation ◽  
Low Frequencies ◽  
Functional Regions ◽  
Wide Range ◽  
Bold Responses ◽  
Oxygenation Level ◽  
The Relationship

The relationship between electrophysiological and functional magnetic resonance imaging (fMRI) signals remains poorly understood. To date, studies have required invasive methods and have been limited to single functional regions and thus cannot account for possible variations across brain regions. Here we present a method that uses fMRI data and singe-trial electroencephalography (EEG) analyses to assess the spatial and spectral dependencies between the blood-oxygenation-level-dependent (BOLD) responses and the noninvasively estimated local field potentials (eLFPs) over a wide range of frequencies (0–256 Hz) throughout the entire brain volume. This method was applied in a study where human subjects completed separate fMRI and EEG sessions while performing a passive visual task. Intracranial LFPs were estimated from the scalp-recorded data using the ELECTRA source model. We compared statistical images from BOLD signals with statistical images of each frequency of the eLFPs. In agreement with previous studies in animals, we found a significant correspondence between LFP and BOLD statistical images in the gamma band (44–78 Hz) within primary visual cortices. In addition, significant correspondence was observed at low frequencies (<14 Hz) and also at very high frequencies (>100 Hz). Effects within extrastriate visual areas showed a different correspondence that not only included those frequency ranges observed in primary cortices but also additional frequencies. Results therefore suggest that the relationship between electrophysiological and hemodynamic signals thus might vary both as a function of frequency and anatomical region.

scholarly journals An implant for long-term cervical vagus nerve stimulation in mice

2020 ◽  
Author(s):  
Ibrahim T. Mughrabi ◽  
Jordan Hickman ◽  
Naveen Jayaprakash ◽  
Eleni S. Papadoyannis ◽  
Adam Abbas ◽  
...  
Keyword(s):  
Heart Rate ◽  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Therapeutic Potential ◽  
Therapeutic Implications ◽  
Wide Range ◽  
Heart Rate Threshold

AbstractVagus nerve stimulation (VNS) is a neuromodulation therapy with the potential to treat a wide range of chronic conditions in which inflammation is implicated, including type 2 diabetes, obesity, atherosclerosis and heart failure. Many of these diseases have well-established mouse models but due to the significant surgical and engineering challenges that accompany a reliable interface for long-term VNS in mice, the therapeutic implications of this bioelectronic approach remain unexplored. Here, we describe a long-term VNS implant in mice, developed at 3 research laboratories and validated for between-lab reproducibility. Implant functionality was evaluated over 3-8 weeks in 81 anesthetized or conscious mice by determining the stimulus intensity required to elicit a change in heart rate (heart rate threshold, HRT). HRT was also used as a method to standardize stimulation dosing across animals. Overall, 60-90% of implants produced stimulus-evoked physiological responses for at least 4 weeks, with HRT values stabilizing after the second week of implantation. Furthermore, stimulation delivered through 6-week-old implants decreased TNF levels in a subset of mice with acute inflammation caused by endotoxemia. Histological examination of 4- to 6-week-old implants revealed fibrotic encapsulation and no gross fiber loss. This implantation and dosing approach provide a tool to systematically investigate the therapeutic potential of long-term VNS in chronic diseases modeled in the mouse, the most widely used vertebrate species in biomedical research.

Abstract T MP24: Vagus Nerve Stimulation Improves Motor Function After Chronic Stroke in Adult Rats

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Navid Khodaparast ◽  
Reema Casavant ◽  
Andrea Ruiz ◽  
Robert L Rennaker ◽  
Michael P Kilgard
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Recovery Of Function ◽  
Chronic Stroke ◽  
Sprague Dawley ◽  
Adult Rats ◽  
Ischemic Lesion ◽  
Treatment Groups ◽  
Hit Rate

Background: Stroke is the leading cause of serious long-term disability. Currently, there is no effective treatment for chronic stroke patients. Neuroplasticity within motor circuitry is believed to support recovery of function after stroke. We have developed a method using vagus nerve stimulation (VNS) paired with motor training to drive robust, specific plasticity in the motor cortex. Our recent studies indicated that VNS paired with rehab training significantly enhances recovery of forelimb function after cortical ischemic stroke. To further the translation potential of our therapy, we accessed the hypothesis that delivering VNS paired with rehab may improve functional recovery in rats that demonstrated chronic forelimb impairments. Methods: All female Sprague Dawley rats were trained on the Isometric Pull Task, which quantifiably measures forelimb force generation. Rats that achieved 5 consecutive days of over 85% hit rate on this task were given a unilateral cortical-subcortical ischemic lesion via injections of a vasoconstrictive peptide, endothelin-1. Following the lesion, rats returned to their home cage, and did not begin rehab training until 5 weeks post-lesion. Upon return, post-lesion forelimb impairment was accessed with the same task parameters used during pre-lesion training, which allowed for a direct comparison of performance. Rats were assigned to balanced treatment groups based on post-lesion baseline hit rate. Treatment groups consisted of VNS delivered during rehab training (Paired VNS; n=10), VNS delivered two hours after rehab training (Delayed VNS; n=10), and rehab training without VNS (Rehab; n=10). Results: At five weeks post-lesion, the unilateral ischemic insult significantly worsened performance in all three groups compared to pre-lesion (Paired VNS: 29.8 ± 5.7%, paired t-test, P < 0.001; Delayed VNS: 24.6 ± 2.7%, P < 0.001; Rehab: 30.4 ± 4.7%, P < 0.001). Following our therapy, the Paired VNS group demonstrated significantly better performance than both control groups (Paired VNS: 81.6 ± 2.3%, P < 0.01; Delayed VNS: 53.2 ± 6.5%, P < 0.01; Rehab: 49.8 ± 6.8%, P < 0.01). Conclusion: Our results indicate that VNS paired with rehab training can further enhance recovery of forelimb function in chronically impaired rats.

scholarly journals Grasping the Intentions of Others: The Perceived Intentionality of an Action Influences Activity in the Superior Temporal Sulcus during Social Perception

2004 ◽  
Vol 16 (10) ◽  
pp. 1706-1716 ◽  
Author(s):  
Kevin A. Pelphrey ◽  
James P. Morris ◽  
Gregory McCarthy
Keyword(s):  
Social Perception ◽  
Cognitive Neuroscience ◽  
Time Course ◽  
Brain Activity ◽  
Superior Temporal Sulcus ◽  
Blood Oxygenation ◽  
Passive Viewing ◽  
Oxygenation Level ◽  
Cortical Regions ◽  
The Right

An explication of the neural substrates for social perception is an important component in the emerging field of social cognitive neuroscience and is relevant to the field of cognitive neuroscience as a whole. Prior studies from our laboratory have demonstrated that passive viewing of biological motion (Pelphrey, Mitchell, et al., 2003; Puce et al., 1998) activates the posterior superior temporal sulcus (STS) region. Furthermore, recent evidence has shown that the perceived context of observed gaze shifts (Pelphrey, Singerman, et al., 2003; Pelphrey et al., 2004) modulates STS activity. Here, using event-related functional magnetic resonance imaging at 4 T, we investigated brain activity in response to passive viewing of goal- and non-goal- directed reaching-to-grasp movements. Participants viewed an animated character making reaching-to-grasp movements either toward (correct) or away (incorrect) from a blinking dial. Both conditions evoked significant posterior STS activity that was strongly right lateralized. By examining the time course of the blood oxygenation level-dependent response from areas of activation, we observed a functional dissociation. Incorrect trials evoked significantly greater activity in the STS than did correct trials, while an area posterior and inferior to the STS (likely corresponding to the MT/V5 complex) responded equally to correct and incorrect movements. Parietal cortical regions, including the superior parietal lobule and the anterior intraparietal sulcus, also responded equally to correct and incorrect movements, but showed evidence for differential responding based on the hand and arm (left or right) of the animated character used to make the reaching-to-grasp movement. The results of this study further suggest that a region of the right posterior STS is involved in analyzing the intentions of other people's actions and that activity in this region is sensitive to the context of observed biological motions.

scholarly journals Brain networks and cognitive impairment in Parkinson′s disease

2020 ◽  
Author(s):  
Rosaria Rucco ◽  
Anna Lardone ◽  
marianna Liparoti ◽  
Emahnuel Troisi Lopez ◽  
Rosa De Micco ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Functional Connectivity ◽  
Large Scale ◽  
Brain Activity ◽  
Brain Networks ◽  
Motor Impairment ◽  
Brain Network ◽  
Topological Features ◽  
Delta Band ◽  
Wide Range

Aim The aim of the present study is to investigate the relations between both functional connectivity and brain networks with cognitive decline, in patients with Parkinson′s disease (PD). Introduction PD phenotype is not limited to motor impairment but, rather, a wide range of non-motor disturbances can occur, cognitive impairment being one of the commonest. However, how the large-scale organization of brain activity differs in cognitively impaired patients, as opposed to cognitively preserved ones, remains poorly understood. Methods Starting from source-reconstructed resting-state magnetoencephalography data, we applied the PLM to estimate functional connectivity, globally and between brain areas, in PD patients with and without cognitive impairment (respectively PD-CI and PD-NC), as compared to healthy subjects (HS). Furthermore, using graph analysis, we characterized the alterations in brain network topology and related these, as well as the functional connectivity, to cognitive performance. Results We found reduced global and nodal PLM in several temporal (fusiform gyrus, Heschl′s gyrus and inferior temporal gyrus), parietal (postcentral gyrus), and occipital (lingual gyrus) areas within the left hemisphere, in the gamma band, in PD-CI patients, as compared to PD-NC and HS. With regard to the global topological features, PD-CI patients, as compared to HS and PD-NC patients, showed differences in multi frequencies bands (delta, alpha, gamma) in the Leaf fraction, Tree hierarchy (both higher in PD-CI) and Diameter (lower in PD-CI). Finally, we found statistically significant correlations between the MoCA test and both the Diameter in delta band and the Tree Hierarchy in the alpha band. Conclusion Our work points to specific large-scale rearrangements that occur selectively in cognitively compromised PD patients and correlated to cognitive impairment.

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