Robin at Caputron dropped me a note to let me know they are now carrying the Foc.us V2 device. Purchased alone, it does not include electrodes, but there is an option to add their ‘starter kit’ which includes the Caputron Universal Strap, Caputron Banana Adapter Cable for Focus Device, and Choice of 2×2 or 3×3 Electrodes. (Use diytdcs at checkout for generous discount). Foc.us V2 Device at Caputron.
If what attracted you to tDCS is all the news (and hype) around the possible benefits, cognitive and otherwise, that tDCS may provide, then I recommend the Foc.us V2 device. It’s had a thorough going over, and apart from the (then included) electrodes, proved to be an amazing piece of gear. tDCS, tACS, tRNS, tPCS in a single sub $300 unit with a software interface!
Banana Plug for Foc.us
Elsewhere on the blog I’ve stated that I recommend the ActivaDose ll device. This is an FDA approved device – it’s NOT FDA approved for tDCS – it’s approval is for use as an Iontophoresis device. The point is that the electronics and workmanship have attained an FDA level of approval. It’s simple and straightforward to use.
The only reason I haven’t recommended other tDCS devices on the market is because I’m not in a position to analyze the quality of their workmanship myself. I recommend the Activadose ll because people looking to experiment with tDCS for the treatment of depression can’t be assumed to have a toolset for determining the mechanical workmanship of an electrical device they’re going to be attaching to their heads! The Activadose ll, an FDA approved device, at least assures the buyer the device itself is of high quality. It’s also more likely to retain some resale value in the event someone decides later on to sell it.
I recommend the Foc.us V2 because of it’s variety of stimulation modes. Folks who are sophisticated enough about neurostimulation to be experimenting with cognitive enhancement would obviously benefit from having the option to test other forms of stimulation that frequently come up in the scientific literature.
When you use code diytdcs at checkout at Caputron you get a discount, and I get a small commission.
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)
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
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.
In the meantime here are a couple of basic brain info sites I found. These tend toward more basic information. Healthline Brain Map
Cold Springs Harbor 3d Brain Map
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.