scholarly journals Human Sensation of Transcranial Electric Stimulation

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Fan-Gang Zeng ◽  
Phillip Tran ◽  
Matthew Richardson ◽  
Shuping Sun ◽  
Yuchen Xu
Keyword(s):  
Auditory Nerve ◽  
Electric Stimulation ◽  
Stimulus Frequency ◽  
Low Frequency ◽  
Electrode Position ◽  
Computer Interfaces ◽  
Transcranial Alternating Current Stimulation ◽  
Transcranial Electric Stimulation ◽  
Somatic Sensation ◽  
Deep Brain

Abstract Noninvasive transcranial electric stimulation is increasingly being used as an advantageous therapy alternative that may activate deep tissues while avoiding drug side-effects. However, not only is there limited evidence for activation of deep tissues by transcranial electric stimulation, its evoked human sensation is understudied and often dismissed as a placebo or secondary effect. By systematically characterizing the human sensation evoked by transcranial alternating-current stimulation, we observed not only stimulus frequency and electrode position dependencies specific for auditory and visual sensation but also a broader presence of somatic sensation ranging from touch and vibration to pain and pressure. We found generally monotonic input-output functions at suprathreshold levels, and often multiple types of sensation occurring simultaneously in response to the same electric stimulation. We further used a recording circuit embedded in a cochlear implant to directly and objectively measure the amount of transcranial electric stimulation reaching the auditory nerve, a deep intercranial target located in the densest bone of the skull. We found an optimal configuration using an ear canal electrode and low-frequency (<300 Hz) sinusoids that delivered maximally ~1% of the transcranial current to the auditory nerve, which was sufficient to produce sound sensation even in deafened ears. Our results suggest that frequency resonance due to neuronal intrinsic electric properties need to be explored for targeted deep brain stimulation and novel brain-computer interfaces.

scholarly journals Can transcranial electric stimulation with multiple electrodes reach deep targets?

2018 ◽  
Author(s):  
Yu Huang ◽  
Lucas C Parra
Keyword(s):  
Electric Stimulation ◽  
Target Location ◽  
Head Model ◽  
Multiple Electrodes ◽  
Realistic Head Model ◽  
Transcranial Electric Stimulation ◽  
The Brain ◽  
Deep Target ◽  
Deep Brain ◽  
Intense Stimulation

To reach a deep target in the brain with transcranial electric stimulation (TES), currents have to pass also through the cortical surface. Thus, it is generally thought that TES cannot achieve focal deep brain stimulation. Recent efforts with interfering waveforms and pulsed stimulation have argued that one can achieve deeper or more intense stimulation in the brain. Here we argue that conventional transcranial stimulation with multiple current sources is just as effective as these new approaches. The conventional multi-electrode approach can be numerically optimized to maximize intensity or focality at a desired target location. Using such optimal electrode configurations we find in a detailed and realistic head model that deep targets may in fact be strongly stimulated, with cerebrospinal fluid guiding currents deep into the brain.

scholarly journals Novel flexible cap for application of transcranial electric stimulation: a usability study

2020 ◽  
Author(s):  
Alexander Hunold ◽  
Daniela Ortega ◽  
Klaus Schellhorn ◽  
Jens Haueisen
Keyword(s):  
Healthy Volunteers ◽  
Electric Stimulation ◽  
Electrode Configuration ◽  
Electrode Position ◽  
Usability Study ◽  
Subjective Evaluations ◽  
Transcranial Electric Stimulation ◽  
New Applications

Abstract BackgroundAdvances in transcranial electric stimulation (TES) were hampered by the conventional rubber electrodes manually attached to the head with rubber bands. This procedure limited montages to a few electrodes, was error prone with respect to electrode configurations and was burdensome for participants and operators. A newly developed flexible cap with integrated textile stimulation electrodes was compared to the conventional setup of rubber electrodes fixated by rubber bands, with respect to usability and reliability. Two operators applied both setups to twenty healthy volunteers participating in the study. Electrode position and impedance measures as well as subjective evaluations from participants and operators were obtained throughout the stimulation sessions. ResultsOur results demonstrated the superiority of the flexible cap by means of significantly higher electrode configuration reproducibility and a more efficient application. Both, operators and volunteers evaluated the flexible cap as easier to use and more comfortable to wear when compared to the conventional setup. ConclusionIn conclusion, the new cap improves existing and opens new applications scenarios for TES.

scholarly journals A Simulation on Relation between Power Distribution of Low-Frequency Field Potentials and Conducting Direction of Rhythm Generator Flowing through 3D Asymmetrical Brain Tissue

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 900
Author(s):  
Hao Cheng ◽  
Manling Ge ◽  
Abdelkader Nasreddine Belkacem ◽  
Xiaoxuan Fu ◽  
Chong Xie ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Power Distribution ◽  
Low Frequency ◽  
Field Potentials ◽  
Spatial Spread ◽  
Rhythm Generator ◽  
Equivalent Dipole ◽  
Head Surface ◽  
Brain Rhythm ◽  
Deep Brain

Although the power of low-frequency oscillatory field potentials (FP) has been extensively applied previously, few studies have investigated the influence of conducting direction of deep-brain rhythm generator on the power distribution of low-frequency oscillatory FPs on the head surface. To address this issue, a simulation was designed based on the principle of electroencephalogram (EEG) generation of equivalent dipole current in deep brain, where a single oscillatory dipole current represented the rhythm generator, the dipole moment for the rhythm generator’s conducting direction (which was orthogonal and rotating every 30 degrees and at pointing to or parallel to the frontal lobe surface) and the (an)isotropic conduction medium for the 3D (a)symmetrical brain tissue. Both the power above average (significant power value, SP value) and its space (SP area) of low-frequency oscillatory FPs were employed to respectively evaluate the strength and the space of the influence. The computation was conducted using the finite element method (FEM) and Hilbert transform. The finding was that either the SP value or the SP area could be reduced or extended, depending on the conducting direction of deep-brain rhythm generator flowing in the (an)isotropic medium, suggesting that the 3D (a)symmetrical brain tissue could decay or strengthen the spatial spread of a rhythm generator conducting in a different direction.

scholarly journals Deep Brain Stimulation of the Posterior Insula in Chronic Pain: A Theoretical Framework

2021 ◽  
Vol 11 (5) ◽  
pp. 639
Author(s):  
David Bergeron ◽  
Sami Obaid ◽  
Marie-Pierre Fournier-Gosselin ◽  
Alain Bouthillier ◽  
Dang Khoa Nguyen
Keyword(s):  
Chronic Pain ◽  
Electrical Stimulation ◽  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
High Frequency ◽  
Brain Lesion ◽  
Low Frequency ◽  
Posterior Insula ◽  
Deep Brain ◽  
Stimulation Of

Introduction: To date, clinical trials of deep brain stimulation (DBS) for refractory chronic pain have yielded unsatisfying results. Recent evidence suggests that the posterior insula may represent a promising DBS target for this indication. Methods: We present a narrative review highlighting the theoretical basis of posterior insula DBS in patients with chronic pain. Results: Neuroanatomical studies identified the posterior insula as an important cortical relay center for pain and interoception. Intracranial neuronal recordings showed that the earliest response to painful laser stimulation occurs in the posterior insula. The posterior insula is one of the only regions in the brain whose low-frequency electrical stimulation can elicit painful sensations. Most chronic pain syndromes, such as fibromyalgia, had abnormal functional connectivity of the posterior insula on functional imaging. Finally, preliminary results indicated that high-frequency electrical stimulation of the posterior insula can acutely increase pain thresholds. Conclusion: In light of the converging evidence from neuroanatomical, brain lesion, neuroimaging, and intracranial recording and stimulation as well as non-invasive stimulation studies, it appears that the insula is a critical hub for central integration and processing of painful stimuli, whose high-frequency electrical stimulation has the potential to relieve patients from the sensory and affective burden of chronic pain.

scholarly journals Safety evaluation of a new setup for transcranial electric stimulation during magnetic resonance imaging

2021 ◽  
Vol 14 (3) ◽  
pp. 488-497
Author(s):  
Fróði Gregersen ◽  
Cihan Göksu ◽  
Gregor Schaefers ◽  
Rong Xue ◽  
Axel Thielscher ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Electric Stimulation ◽  
Safety Evaluation ◽  
Resonance Imaging ◽  
Transcranial Electric Stimulation

Induction of long-term potentiation without participation of N-methyl-D-aspartate receptors in kitten visual cortex

1991 ◽  
Vol 65 (1) ◽  
pp. 20-32 ◽  
Author(s):  
Y. Komatsu ◽  
S. Nakajima ◽  
K. Toyama
Keyword(s):  
Nmda Receptors ◽  
Stimulus Frequency ◽  
Low Frequency ◽  
Nmda Antagonist ◽  
Long Term Potentiation ◽  
Conditioning Stimulation ◽  
Postsynaptic Potential ◽  
Term Potentiation ◽  
Stimulation Of

1. Intracellular recording was made from layer II-III cells in slice preparations of kitten (30-40 days old) visual cortex. Low-frequency (0.1 Hz) stimulation of white matter (WM) usually evoked an excitatory postsynaptic potential (EPSP) followed by an inhibitory postsynaptic potential (IPSP). The postsynaptic potentials (PSPs) showed strong dependence on stimulus frequency. Early component of EPSP and IPSP evoked by weak stimulation both decreased monotonically at frequencies greater than 0.5-1 Hz. Strong stimulation similarly depressed the early EPSP at higher frequencies (greater than 2 Hz) and replaced the IPSP with a late EPSP, which had a maximum amplitude in the stimulus frequency range of 2-5 Hz. 2. Very weak WM stimulation sometimes evoked EPSPs in isolation from IPSPs. The falling phase of the EPSP revealed voltage dependence characteristic to the responses mediated by N-methyl-D-aspartate (NMDA) receptors and was depressed by application of an NMDA antagonist DL-2-amino-5-phosphonovalerate (APV), whereas the rising phase of the EPSP was insensitive to APV. 3. The early EPSPs followed by IPSPs were insensitive to APV but were replaced with a slow depolarizing potential by application of a non-NMDA antagonist 6,7-dinitro-quinoxaline-2,3-dione (DNQX), indicating that the early EPSP is mediated by non-NMDA receptors. The slow depolarization was mediated by NMDA receptors because it was depressed by membrane hyperpolarization or addition of APV. 4. The late EPSP evoked by higher-frequency stimulation was abolished by APV, indicating that it is mediated by NMDA receptors, which are located either on the recorded cell or on presynaptic cells to the recorded cells. 5. Long-term potentiation (LTP) of EPSPs was examined in cells perfused with solutions containing 1 microM bicuculline methiodide (BIM), a gamma-aminobutyric acid (GABA) antagonist. WM was stimulated at 2 Hz for 15 min as a conditioning stimulus to induce LTP, and the resultant changes were tested by low-frequency (0.1 Hz) stimulation of WM. 6. LTP of early EPSPs occurred in more than one-half of the cells (8/13) after strong conditioning stimulation. The rising slope of the EPSP was increased 1.6 times on average. 7. To test involvement of NMDA receptors in the induction of LTP in the early EPSP, the effect of conditioning stimulation was studied in a solution containing 100 microM APV, which was sufficient to block completely synaptic transmission mediated by NMDA receptors. LTP occurred in the same frequency and magnitude as in control solution.

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