Waveforms
Noninvasive brain stimulation uses gentle electrical currents applied to the scalp to reversibly modulate brain function. The little ‘t’ stands for transcranial, and the shape of the waveform determine how neural activity is modified. Learn the lingo below.
tDCS
tPCS
tACS
tIFS
tDCS stands for transcranial direct current stimulation. Positive currents enter the head and negative currents leave the head.
tPCS stands for pulsed current stimulation. Currents in tPCS are brief but repeat over and over.
tACS stands for transcranial alternating current stimulation, where currents oscillate over time.
tIFS stands for transcranial interferential stimulation and is derived by combining two AC waves.
Electrodes
Definitions
The materials that deliver the stimulation, such as stainless steel or carbon rubber. But don’t confuse the electrode with the sponge that is the interface placed between the electrode and scalp to reduce skin sensations.
The electrodes that output (positive) current and are thereby represented with a plus sign. An anode can become a cathode if the sign of the current is reversed, for example, during tACS.
The electrodes that input (negative) current and are thereby represented with a minus sign. A cathode can become an anode if the sign of the current is reversed, for example, during tACS.
Montages describe how the electrodes are positioned on the scalp. There are a number of montages available for different wellness applications. Although we do not prescribe any specific montage, we can provide you with resources so that you can make an informed decision for you own wellness needs.
Anodes enhance
Cathodes calm
sinusoids coordinate
Positive currents enhance brain activity. These currents are weak and don’t directly modulate the brain. Rather, they promote enhanced activity by increasing the probability of neural firing.
Negative currents counter and complement the positive currents. The negative electrode is called the cathode, which serves to calm or quiet brain activity.
Sinusoidal currents have a push (positive) and pull (negative). These currents help coordinate brain activity, so they act like a metronome to keep a rhythm or beat.