— melanie segado (@sciencelaer) August 29, 2016
Dr. Williams at SpeakWisdom takes a look at the new focus electrodes as well as new Caputron Amrex-style electrodes. Electrode Wars! (Well Not Quite)
foc.us (famous for the foc.us V2 brain stimulation device and the new Go Flow tDCS device) is just releasing a new sponge electrode system for the V2 and Go Flow that is very interesting! It consists of a rubber-like shell (about 2×2) and sponges that when inserted result in a 1.25 x 1.25 inch sponge contact area. To connect to the foc.us sponge electrodes, you need a special V2/Go Flow cable that attaches magnetically to the electrode shell. That means the problem of having an electrode jerked off of your head should you become tangled somehow goes away. This is a vastly better connection technology than the banana plug and socket used by many manufactures.
Many of the leading tDCS researchers contribute to this Open Access article on clinical application of transcranial electrical stimulation (tES) techniques. Read it online, or download the pdf. (HatTip to Reddit user gi67)
- 1. Introduction
- 2. Transcranial direct current stimulation
- 2.1. Selecting and preparing electrodes and contact medium
- 2.2. Selecting and preparing electrode placement
- 2.3. Selecting a stimulation protocol
- 2.4. Use of blinding and sham
- 2.5. Safety versus tolerability
- 2.6. Considerations for transcutaneous spinal DC stimulation (tsDCS)
- 2.7. Considerations for cerebellar tDCS
- 2.8. Selecting a stimulator
- 3. Transcranial alternating current stimulation (tACS)
- 4. Monitoring physiological effects of tES
- 4.1. Monitoring physiological effects of tES with TMS
- 4.2. Monitoring physiological effects of tES with electroencephalography (EEG) and event-related potentials (ERPs)
- 4.3. Monitoring physiological effects of tES with magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS)
- 5. Monitoring functional effects of tES
- 6. tDCS/tACS/tRNS in animal preparations
- 7. tDCS and models of electric current through the brain
- 8. tES ethics
- 9. Concluding remarks
This instructional video demonstrates the correct way to measure and place electrodes. In a clinical setting, with a medical grade tDCS device (Soterix), a subject is measured for electrode placement on the primary motor cortex. The dorsolateral prefrontal cortex region is also shown. This is the first time I’ve seen the video on Youtube (making it easy to share). Previously it could only be found here, where an associated pdf which includes illustrations is also made available.
[Note (updated 8/9/15): Alex is using a research version of the mindGear device. The device as available to the general public does not include a tDCS program.]
The folks at the Neural Engineering Group (associated with Marom Bikson’s NY City College Neural Engineering Lab) are producing a series on tDCS. Here is their first episode!
My Notes: Could you force an action potential with tDCS? (TMS does)
Visual memory improved by non-invasive brain stimulation (paywall)
Richard P. Chi, Felipe Fregni, Allan W. Snyder
Dosage: mA x time, i.e. 30 mA minutes could be 1.5mA for 20 minutes.
Memory improvement montage: Anode between T8 & FT8, Cathode between T7 & FT7
Foc.us recently released a new set of electrodes that addresses many of the issues customers and reviewers had with previous releases.
Also very impressed to see this on their website.
Coming soon… foc.us+
Connect and share with others like you
Using foc.us+ you can find experts who can help tailor the perfect program for your neuro-modulation needs. Track your progress, monitor your improvements. take charge
Foc.us is definitely listening and doing their best to stay one step ahead of everybody else.
Update 9/6/12: Found for the first time, a study which equates electrode placement directly with the 10/20 positioning system. The study, Modulating activity in the motor cortex affects performance for the two hands differently depending upon which hemisphere is stimulated, was published in the European Journal of Neuroscience in 2008 and is available to download as a pdf or read in Quick View.
On each day, there was one session for anodal and one for cathodal tDCS, administered while the participants sat in an office chair. On the first day, participants also underwent one session of sham tDCS. For the anodal and cathodal sessions, 1 mA tDCS was applied for 20 min. On one of the testing days, the active electrode was positioned over the participant’s left- hemisphere motor region, centered on C3 of the 10–20 international electroencephalogram system; on the other day, the active electrode was positioned over the motor region of the right hemisphere (centered on C4 of the 10–20 electroencephalogram system). The correspon- dence between C3, C4 and the primary motor cortices of the left and right hemispheres, respectively, has been confirmed by neuroimaging studies (Homan et al., 1987; Herwig et al., 2003; Okamoto et al., 2004)
While the 10/20 positioning system (wikipedia, pdf) does seem straight-forward and easy to understand, most of the electrode sites mentioned in the publications I’m reading don’t refer to it in describing where electrodes are being placed. You’re more likely to see something like: “…after bifrontal tDCS with the anode over the right and the cathode over the left dorsolateral prefrontal cortex (DLPFC).”
But if laypeople are going to be experimenting on themselves, wouldn’t they need some sort of standard reference to enable sharing of specific electrode sites? Wouldn’t you like to be able to say something like, I placed the anode over the right dorsolateral prefronal cortex at F3 and the cathode over the left at F7? In that way it would be easy for someone else to replicate. I was looking for a diagram that would map the 10/20 system over brain regions, but didn’t find exactly what I was looking for. If you have any ideas about this please share in the comments.
Soterix is the company Marom Bikson is part of. As far as I can see, Soterix is the only company currently pursuing the idea of HD tDCS, where multiple anodes allow for a more clearly defined flow of current. Both these videos are simply demonstrating how to set up the Soterix brand electrodes.