Vagus nerve stimulation during training fails to improve learning in healthy rats.

Learning new skills requires neuroplasticity. Vagus nerve stimulation (VNS) during sensory and motor events can increase neuroplasticity in networks related to these events and might therefore serve to facilitate learning on sensory and motor tasks. We tested if VNS could broadly improve learning on a wide variety of tasks across different skill domains in healthy, female adult rats.

Characterization of an Algorithm for Autonomous, Closed-Loop Neuromodulation During Motor Rehabilitation.

Background: Recent evidence demonstrates that manually triggered vagus nerve stimulation (VNS) combined with rehabilitation leads to increased recovery of upper limb motor function after stroke. This approach is premised on studies demonstrating that the timing of stimulation relative to movements is a key determinant in the effectiveness of this approach.

Objective: The overall goal of the study was to identify an algorithm that could be used to automatically trigger VNS on the best movements during rehabilitative exercises while maintaining a desired interval between stimulations to reduce the burden of manual stimulation triggering.

Vagus Nerve Stimulation Must Occur During Tactile Rehabilitation to Enhance Somatosensory Recovery.

Chronic sensory loss is a common and undertreated consequence of many forms of neurological injury. Emerging evidence indicates that vagus nerve stimulation (VNS) delivered during tactile rehabilitation promotes recovery of somatosensation. Here, we systematically varied the timing of VNS relative to tactile rehabilitation to determine the paradigm that yields the greatest degree of somatosensory recovery after peripheral nerve injury (PNI).

Usage of RePlay as a Take-Home System to Support High-Repetition Motor Rehabilitation After Neurological Injury.

Stroke is a leading cause of chronic motor disability. While physical rehabilitation can promote functional recovery, several barriers prevent patients from receiving optimal rehabilitative care. Easy access to at-home rehabilitative tools could increase patients' ability to participate in rehabilitative exercises, which may lead to improved outcomes.

Optimizing Dosing of Vagus Nerve Stimulation for Stroke Recovery.

Vagus nerve stimulation (VNS) paired with rehabilitative training enhances recovery of function in models of stroke and is currently under investigation for use in chronic stroke patients. Dosing is critical in translation of pharmacological therapies, but electrical stimulation therapies often fail to comprehensively explore dosing parameters in preclinical studies. Varying VNS parameters has non-monotonic effects on plasticity in the central nervous system, which may directly impact efficacy for stroke.

A limited range of vagus nerve stimulation intensities produce motor cortex reorganization when delivered during training.

Pairing vagus nerve stimulation (VNS) with rehabilitation has emerged as a potential strategy to improve recovery after neurological injury, an effect ascribed to VNS-dependent enhancement of synaptic plasticity. Previous studies demonstrate that pairing VNS with forelimb training increases forelimb movement representations in motor cortex. However, it is not known whether VNS-dependent enhancement of plasticity is restricted to forelimb training or whether VNS paired with other movements could induce plasticity of other motor representations.

Efficient parameters of vagus nerve stimulation to enhance extinction learning in an extinction-resistant rat model of PTSD.

Vagus nerve stimulation (VNS) has shown promise as an adjuvant treatment for posttraumatic stress disorder (PTSD), as it enhances fear extinction and reduces anxiety symptoms in multiple rat models of this condition. Yet, identification of the optimal stimulation paradigm is needed to facilitate clinical translation of this potential therapy. Using an extinction-resistant rat model of PTSD, we tested whether varying VNS intensity and duration could maximize extinction learning while minimizing the total amount of stimulation.

Vagus nerve stimulation reverses the extinction impairments in a model of PTSD with prolonged and repeated trauma.

We have shown that vagus nerve stimulation (VNS) enhances extinction of conditioned fear and reduces anxiety in rat models of PTSD using moderate stress. However, it is still unclear if VNS can be effective in enhancing extinction of severe fear after prolonged and repeated trauma. Severe fear was induced in adult male rats by combining single prolonged stress (SPS) and protracted aversive conditioning (PAC).

Closed-loop neuromodulation restores network connectivity and motor control after spinal cord injury.

Recovery from serious neurological injury requires substantial rewiring of neural circuits. Precisely-timed electrical stimulation could be used to restore corrective feedback mechanisms and promote adaptive plasticity after neurological insult, such as spinal cord injury (SCI) or stroke. This study provides the first evidence that closed-loop vagus nerve stimulation (CLV) based on the synaptic eligibility trace leads to dramatic recovery from the most common forms of SCI.

The M-Maze task: An automated method for studying fear memory in rats exposed to protracted aversive conditioning.

Background: Fear conditioning (FC) in rodents is the most used animal model to investigate the neurobiology of posttraumatic stress disorder (PTSD). Although research using FC has generated a better understanding of fear memories, studies often rely on mild or moderate FC training and behavioral analysis generally focuses on measuring freezing responses within few test sessions.

New Method: We introduce the M-Maze task, a system that measures extinction of conditioned fear using suppression of operant behavior.

Traumatic Brain Injury Occludes Training-Dependent Cortical Reorganization in the Contralesional Hemisphere.

Rehabilitative training drives plasticity in the ipsilesional (injured) motor cortex that is believed to support recovery of motor function after either stroke or traumatic brain injury (TBI). In addition, adaptive plasticity in the contralesional (uninjured) motor cortex has been well-characterized in the context of stroke. While similar rehabilitation-dependent plasticity in the intact hemisphere may occur after TBI, this has yet to be thoroughly explored.

Forelimb training drives transient map reorganization in ipsilateral motor cortex.

Skilled motor training results in reorganization of contralateral motor cortex movement representations. The ipsilateral motor cortex is believed to play a role in skilled motor control, but little is known about how training influences reorganization of ipsilateral motor representations of the trained limb. To determine whether training results in reorganization of ipsilateral motor cortex maps, rats were trained to perform the isometric pull task, an automated motor task that requires skilled forelimb use.

Vagus Nerve Stimulation Delivered with Motor Training Enhances Recovery of Function after Traumatic Brain Injury.

Traumatic Brain Injury (TBI) is one of the largest health problems in the United States, and affects nearly 2 million people every year. The effects of TBI, including weakness and loss of coordination, can be debilitating and last years after the initial injury. Recovery of motor function is often incomplete.