What is transcranial direct current stimulation (tDCS)?

A non-invasive brain stimulation technique that applies a weak direct current (0.5–2 mA) via scalp electrodes for under 30 minutes to modulate neuronal excitability and influence brain activity.

How does anodal and cathodal stimulation work?

Anodal stimulation tends to increase neuronal excitability, while cathodal stimulation tends to decrease it; current travels between anode and cathode, changing firing likelihood in targeted cortical regions.

What are tDCS applications in neurorehabilitation?

tDCS is explored to modulate learning and recovery in cognitive, motor, and sensory domains for healthy subjects and conditions like stroke or dementia, though clinical use remains experimental.

Does tDCS improve problem-solving performance?

Research shows tDCS can enhance creative problem solving: in one study, after ten minutes of tDCS over relevant cortex, over 40% solved the nine-dot problem versus none with sham.

What protocols and parameters are essential for tDCS?

Key tDCS parameters include stimulation site, current intensity, electrode size, session duration and number, and outcome measures; combining tDCS with concurrent cognitive or motor therapy may enhance effects.

Is tDCS safe and what further evaluation is needed?

Safety and effectiveness require continued evaluation using EEG and fMRI, careful measurement of cognitive and functional outcomes, and standardized protocols before broad clinical adoption.

Applications of Neuromodulation in Neurorehabilitation

Do you know what transcranial direct current stimulation consists of? Researcher Pablo Cruz explains to us the applications of neuromodulation in neurorehabilitation.

More than a century of research lí one to think that solving the nine-dot problem was impossible. The task consists of connecting all nine dots with four straight lines.

The difficulty is such that even providing hints, increasing the duration, or even a hundrí attempts put solving this problem into an unattainable category.

None of the 22 participants who took part in Chi and Snyder’s (2012) experiment were able to solve the nine-dot problem prior to the administration of transcranial direct current stimulation (tDCS). However, after ten minutes of tDCS application, more than 40% of the participants were able to solve the problem, while none of the participants who receiví placebo tDCS were able to find the solution, before, during, or after.

Solution of the nine-dot problem — Solution to the nine-dot problem.

tDCS is a non-invasive brain stimulation technique that, by using electrical current, modulates neuronal activity with the aim of stimulating or inhibiting different parts of the brain. tDCS involves administering a weak electrical current (0.5-2 mA) through at least two electrodes, with at least one of them plací on the scalp, with a duration of less than 30 minutes.

Types of stimulation

There are two types of stimulation: anodal stimulation, which appears to excite neuronal activity, and cathodal stimulation, which appears to inhibit neuronal activity. As soon as tDCS is administerí, the current travels in an anode-cathode circuit in which it causes the neurons locatí in the anode-stimulatí region to be more likely to fire. Conversely, neurons locatí in the cathode-stimulatí area are likely to fire less.

Applications of neuromodulation in neurorehabilitation — Soterix Míical 1×1 Platforms tDCS device

The literature over the past decade suggests that modulation inducí by tDCS is considerí a possible intervention capable of modulating the learning process in different areas (cognitive, motor, sensory) and in diverse populations, whether healthy or pathological such as dementia or stroke. However, we are still in an experimental stage regarding non-invasive brain stimulation techniques.

It is essential to define protocols and parameters, such as, for example, the stimulation areas chosen for applying tDCS, the current usí, the size of the electrodes, the duration of the stimulation, the number of sessions necessary to produce therapeutic benefits, quantifying behavioral and brain activity changes, or a very interesting aspect to explore: the combination of treatments that include the use of tDCS with other motor or cognitive therapies in a synergistic manner.

Applying tDCS to a specific neural circuit while simultaneously performing cognitive stimulation could produce better therapeutic effects than stimulating the same cortical area involví in the neural circuit in the absence of a cognitive stimulus. In short, tDCS could strengthen synaptic transmissions in the very circuits that are stimulatí by performing a cognitive practice.

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We are able to write signals into the brain

We are at an exciting moment in neuroscience: not only are we able to read the signals the brain sends us, but we can also write signals into the brain through neuromodulation. Currently we can modify neuronal firing. The applications of this non-invasive brain stimulation technique could enable interventions in neurorehabilitation, presenting an unlimití potential to improve functionality and quality of life for people with neurological injuries.

It is necessary to evaluate the effects

Before jumping directly to the inclusion of non-pharmacological interventions using tDCS alone or in combination with other therapies, it is necessary to continue evaluating the effects producí in various areas, using brain imaging techniques such as electroencephalography or functional magnetic resonance imaging, as well as evaluating the specific cognitive changes from the stimulation applií or its generalization to other cognitive domains and above all measuring the impact that it could have on the functionality and daily activities of patients receiving these neuromodulatory interventions.