Epicranial Direct Current Stimulation Suppresses Harmaline Tremor in Rats.

Introduction: Essential tremor (ET) is the most common neurologic movement disorder worldwide. It is characterized by a postural tremor, mostly in the upper extremities, causing difficulties in daily activities that may lead to social exclusion. Some patients with ET do not respond well to or do not tolerate medication.

Frequency-Specific Modulation of Slow-Wave Neural Oscillations via Weak Exogeneous Extracellular Fields Reveals a Resonance Pattern.

Single neurons often exhibit endogenous oscillatory activity centered around a specific frequency band. Transcranial alternating current stimulation (tACS) can generate a weak oscillating extracellular field in the brain that causes subthreshold membrane potential shifts that can affect spike timing at the single neuron level. Many studies have now shown that the endogenous oscillation can be entrained when the tACS frequency matches that of the exogenous extracellular field.

A Computational Modeling Study to Investigate the Use of Epicranial Electrodes to Deliver Interferential Stimulation to Subcortical Regions.

Epicranial cortical stimulation (ECS) is a minimally invasive neuromodulation technique that works by passing electric current between subcutaneous electrodes positioned on the skull. ECS causes a stronger and more focused electric field in the cortex compared to transcranial electric stimulation (TES) where the electrodes are placed on the scalp. However, it is unknown if ECS can target deeper regions where the electric fields become relatively weak and broad.

Biophysical mechanisms of electroconvulsive therapy-induced volume expansion in the medial temporal lobe: A longitudinal in vivo human imaging study.

Background: Electroconvulsive therapy (ECT) applies electric currents to the brain to induce seizures for therapeutic purposes. ECT increases gray matter (GM) volume, predominantly in the medial temporal lobe (MTL). The contribution of induced seizures to this volume change remains unclear.

tDCS peripheral nerve stimulation: a neglected mode of action?

Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation method widely used by neuroscientists and clinicians for research and therapeutic purposes. tDCS is currently under investigation as a treatment for a range of psychiatric disorders. Despite its popularity, a full understanding of tDCS's underlying neurophysiological mechanisms is still lacking.

Investigating the Feasibility of Epicranial Cortical Stimulation Using Concentric-Ring Electrodes: A Novel Minimally Invasive Neuromodulation Method.

Background: Invasive cortical stimulation (ICS) is a neuromodulation method in which electrodes are implanted on the cortex to deliver chronic stimulation. ICS has been used to treat neurological disorders such as neuropathic pain, epilepsy, movement disorders and tinnitus. Noninvasive neuromodulation methods such as transcranial magnetic stimulation and transcranial electrical stimulation (TES) show great promise in treating some neurological disorders and require no surgery.

Validation of the Fetal Lamb Model of Spina Bifida.

A randomized trial demonstrated that fetal spina bifida (SB) repair is safe and effective yet invasive. New less invasive techniques are proposed but are not supported by adequate experimental studies. A validated animal model is needed to bridge the translational gap to the clinic and should mimic the human condition.

Analytical bias accounts for some of the reported effects of tACS on auditory perception.

Background: Transcranial alternating current stimulation (tACS) has been shown to modulate auditory, visual, cognitive and motor function. However, tACS effects can often be small and difficult to reproduce. Thus, the establishment of robust experimental and analysis procedures is of high importance.

tACS motor system effects can be caused by transcutaneous stimulation of peripheral nerves.

Transcranial alternating current stimulation (tACS) is a noninvasive neuromodulation method which has been shown to modulate hearing, motor, cognitive and memory function. However, the mechanisms underpinning these findings are controversial, as studies show that the current reaching the cortex may not be strong enough to entrain neural activity. Here, we propose a new hypothesis to reconcile these opposing results: tACS effects are caused by transcutaneous stimulation of peripheral nerves in the skin and not transcranial stimulation of cortical neurons.

Publisher Correction: Using high-amplitude and focused transcranial alternating current stimulation to entrain physiological tremor.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Using high-amplitude and focused transcranial alternating current stimulation to entrain physiological tremor.

Transcranial alternating current stimulation (tACS) is a noninvasive neuromodulation method that can entrain physiological tremor in healthy volunteers. We conducted two experiments to investigate the effectiveness of high-amplitude and focused tACS montages at entraining physiological tremor. Experiment 1 used saline-soaked sponge electrodes with an extra-cephalic return electrode and compared the effects of a motor (MC) and prefrontal cortex (PFC) electrode location.

Quantitative analysis of motor evoked potentials in the neonatal lamb.

Evoking motor potentials are an objective assessment method for neuromotor function, yet this was to our knowledge never done in neonatal lambs. There is neither a method for standardized quantification of motor evoked potentials (MEPs). We first aimed to evaluate the feasibility of MEP recording in neonatal lambs and test its validity.

Simultaneously Excitatory and Inhibitory Effects of Transcranial Alternating Current Stimulation Revealed Using Selective Pulse-Train Stimulation in the Rat Motor Cortex.

Transcranial alternating current stimulation (tACS) uses sinusoidal, subthreshold, electric fields to modulate cortical processing. Cortical processing depends on a fine balance between excitation and inhibition and tACS acts on both excitatory and inhibitory cortical neurons. Given this, it is not clear whether tACS should increase or decrease cortical excitability.