electrical stimulation

Kendrick Kay

The lab of Dr. Kendrick Kay at the Center for Magnetic Resonance Research at the University of Minnesota is recruiting one or more postdocs. The lab seeks to integrate broad interdisciplinary insights to understand function in the visual system. One postdoc position is on a newly funded NIH R01 to develop, design, and collect a large-scale 7T fMRI dataset that samples a wide range of cognitive tasks on a common set of visual stimuli. The project is being conducted in close collaboration with co-PI Dr. Clayton Curtis (New York University). Activities in this grant include either (i) designing, collecting, and analyzing the large-scale neuroimaging dataset, (ii) technical work focused on extending and expanding the GLMsingle analysis method, and/or (iii) other related experimental or modeling work in visual/cognitive neuroscience. Another postdoc position is aimed towards integrating fMRI and intracranial EEG measurements during visual tasks (NSD-iEEG) and electrical stimulation. The general goal of this effort is to better understand signaling across the visual hierarchy (from early visual to higher order areas ventral temporal cortex and frontal/parietal areas). This project is in collaboration with PI Dr. Dora Hermes (Mayo Clinic).

Seizure control by electrical stimulation: parameters and mechanisms

Seizure suppression by deep brain stimulation (DBS) applies high frequency stimulation (HFS) to grey matter to block seizures. In this presentation, I will present the results of a different method that employs low frequency stimulation (LFS) (1 to 10Hz) of white matter tracts to prevent seizures. The approach has been shown to be effective in the hippocampus by stimulating the ventral and dorsal hippocampal commissure in both animal and human studies respectively for mesial temporal lobe seizures. A similar stimulation paradigm has been shown to be effective at controlling focal cortical seizures in rats with corpus callosum stimulation. This stimulation targets the axons of the corpus callosum innervating the focal zone at low frequencies (5 to 10Hz) and has been shown to significantly reduce both seizure and spike frequency. The mechanisms of this suppression paradigm have been elucidated with in-vitro studies and involve the activation of two long-lasting inhibitory potentials GABAB and sAHP. LFS mechanisms are similar in both hippocampus and cortical brain slices. Additionally, the results show that LFS does not block seizures but rather decreases the excitability of the tissue to prevent seizures. Three methods of seizure suppression, LFS applied to fiber tracts, HFS applied to focal zone and stimulation of the anterior nucleus of the thalamus (ANT) were compared directly in the same animal in an in-vivo epilepsy model. The results indicate that LFS generated a significantly higher level of suppression, indicating LFS of white matter tract could be a useful addition as a stimulation paradigm for the treatment of epilepsy.

Driving human visual cortex, visually and electrically

The development of circuit-based therapeutics to treat neurological and neuropsychiatric diseases require detailed localization and understanding of electrophysiological signals in the human brain. Electrodes can record and stimulate circuits in many ways, and we often rely on non-invasive imaging methods to predict the location to implant electrodes. However, electrophysiological and imaging signals measure the underlying tissue in a fundamentally different manner. To integrate multimodal data and benefit from these complementary measurements, I will describe an approach that considers how different measurements integrate signals across the underlying tissue. I will show how this approach helps relate fMRI and intracranial EEG measurements and provides new insights into how electrical stimulation influences human brain networks.

In pursuit of a universal, biomimetic iBCI decoder: Exploring the manifold representations of action in the motor cortex

My group pioneered the development of a novel intracortical brain computer interface (iBCI) that decodes muscle activity (EMG) from signals recorded in the motor cortex of animals. We use these synthetic EMG signals to control Functional Electrical Stimulation (FES), which causes the muscles to contract and thereby restores rudimentary voluntary control of the paralyzed limb. In the past few years, there has been much interest in the fact that information from the millions of neurons active during movement can be reduced to a small number of “latent” signals in a low-dimensional manifold computed from the multiple neuron recordings. These signals can be used to provide a stable prediction of the animal’s behavior over many months-long periods, and they may also provide the means to implement methods of transfer learning across individuals, an application that could be of particular importance for paralyzed human users. We have begun to examine the representation within this latent space, of a broad range of behaviors, including well-learned, stereotyped movements in the lab, and more natural movements in the animal’s home cage, meant to better represent a person’s daily activities. We intend to develop an FES-based iBCI that will restore voluntary movement across a broad range of motor tasks without need for intermittent recalibration. However, the nonlinearities and context dependence within this low-dimensional manifold present significant challenges.

Effects of Vagus Nerve Stimulation on Arousal State and Cortical Excitation

The vagus nerve is a major pathway by which the brain and the body communicate. Electrical stimulation of the vagus nerve (VNS) is widely used as a therapeutic intervention for epilepsy and there is compelling evidence that it can enhance recovery following stroke. Our work demonstrates that VNS exerts a robust excitatory effect on the brain. First, we establish that VNS triggers an increase in arousal state as measured by behavioral state change. This behavioral state change is linked to an increase in excitatory activity within the cortex. We also show that cholinergic and noradrenergic neuromodulatory pathways are activated by VNS, providing a potential mechanism by which VNS may trigger cortical activation. Importantly, the effect of VNS on neuromodulation and cortical excitation persists in anesthetized mice, demonstrating that VNS-induced cortical activation cannot be fully explained by associated behavioral changes.

How to combine brain stimulation with neuroimaging: "Concurrent tES-fMRI

Transcranial electrical stimulation (tES) techniques, including transcranial alternating and direct current stimulation (tACS and tDCS), are non-invasive brain stimulation technologies increasingly used for modulation of targeted neural and cognitive processes. Integration of tES with human functional magnetic resonance imaging (fMRI) provides a novel avenue in human brain mapping for investigating the neural mechanisms underlying tES. Advances in the field of tES-fMRI can be hampered by the methodological variability between studies that confounds comparability/replicability. To address the technical/methodological details and to propose a new framework for future research, the scientific international network of tES-fMRI (INTF) was founded with two main aims: • To foster scientific exchange between researchers for sharing ideas, exchanging experiences, and publishing consensus articles; • To implement the joint studies through a continuing dialogue with the institutes across the globe. The network organized three international scientific webinars, in which considerable heterogeneities of technical/methodological aspects in studies combining tES with fMRI were discussed along with strategies to help to bridge respective knowledge gaps, and distributes newsletters that are sent regularly to the network members from the Twitter and LinkedIn accounts.

Neuroscience tools for the 99%: On the low-fi development of high-tech lab gear for hands-on neuroscience labs and exploratory research

The public has a fascination with the brain, but little attention is given to neuroscience education prior to graduate studies in brain-related fields. One reason may be the lack of low cost and engaging teaching materials. To address this, we have developed a suite of open-source tools which are appropriate for amateurs and for use in high school, undergraduate, and graduate level educational and research programs. This lecture will provide an overview of our mission to re-engineer research-grade lab equipment using first principles and will highlight basic principles of neuroscience in a "DIY" fashion: neurophysiology, functional electrical stimulation, micro-stimulation effect on animal behavior, neuropharmacology, even neuroprosthesis and optogenetics! Finally, with faculty academic positions becoming a scarce resource, I will discuss an alternative academic career path: entrepreneurship. It is possible to be an academic, do research, publish papers, present at conferences and train students all outside the traditional university setting. I will close by discussing my career path from graduate student to PI/CEO of a startup neuroscience company.

Changes of spike timing in topologically constrained networks under repeated electrical stimulation

Electrical Stimulation of Spinal Circuits for Gait Recovery in Parkinson’s Disease

Investigating the electrical stimulation of subthalamic nucleus for the treatment of cortical stroke

Personalized Transcranial Electrical Stimulation (tES) for Modulation of Associative Memory performance

Single pulse electrical stimulation evoked responses: a pioneering preclinical tool to highlight new specific EEG signatures

Towards Sensation Restoration through Electrical Stimulation in Diabetics

Uncovering the functional connectivity of the human cortical face network with concurrent visual frequency tagging and intracerebral electrical stimulation

Comparing the effects of optogenetic and electrical stimulation of macaque V1 on visual behaviour

FENS Forum 2024

Concurrent transcranial electrical stimulation and magnetoencephalography to explore instant neurophysiological stimulation effects

FENS Forum 2024

Direct electrical stimulation of the human amygdala enhances recognition memory for objects but not scenes

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Effects of non-invasive electrical stimulation on neural and behavioural changes following photothrombotic ischemic stroke

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Electrical stimulation over the parietal cortex induces spatial bias by mediating the influence of visuospatial attention on the temporal dynamics of visuocortical processing

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Exploring the impact of chemical and electrical stimulation on human-iPSCs-derived neural networks coupled to high-density arrays

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Mapping social cognition in patients with gliomas: Preoperative and intraoperative insights from fMRI, MEG, and direct electrical stimulation

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Optimizing electrical stimulation parameters for human-derived neuronal networks: An investigation into the reliability of evoked responses

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Optimizing muscle recruitment by exploring different parameters of intraneural electrical stimulation

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Phase-locked epidural electrical stimulation of the spinal cord in Parkinson's rat model

FENS Forum 2024

Tactile versus electrical stimulation in a conscious somatosensory threshold detection task

FENS Forum 2024

Wakeful slow, oscillatory, transcranial electrical stimulation (so-tES) does not influence overnight memory consolidation, but may alter characteristics of subsequent sleep

FENS Forum 2024