Subdermal EEG/CES/tDCS Implants

Well, this idea first came up in a discussion on brain overclocking.My first thought was creating a device that can actively adjust brain condition based on the user's brain condition and provide real time data about brainwaves without an external sensor array. Any thoughts or suggestions about other functions to incorporate into the device, the device's design, and the implant location? Also, in terms of the technology, how feasible is it at this time?  


  • In all three of the applications you mentioned the location and position of the electrodes on the subject is critical. How would one replicate even a relatively narrow range of electrode configurations with a single implant area?
  • edited October 2013
    My first thought was to use multiple, smaller implants that were linked via Bluetooth or a similar mechanism implanted in the proper locations. Not sure how you would supply power to the devices, unless you wore a hat with an induction device. And that would defeat the purpose of the implant, because you could contain the entire device in the hat... 

    In regard to using a single implant area, you could implant a single device near one of the arteries that supply the scalp with blood, like the Supratrochlear or Supraorbital, and run electrode leads through the arteries to the appropriate locations. 
  • @Cassox
    How risky/invasive would this be in terms of surgery?
  • Well, for electrodes alone easy as pie. All you need is a touch of some conductive metal and such, but the real issue remains what drives the electrodes. Why were you thinking of placing it near an artery? I'd pretty much get as far from an artery as I could. It's true that procedures like angiograms run some pretty hefty hardware through arteries, but we're talking major vessels like the femoral and only for the period of time needed for a procedure. If you left anything in a vessel you'd inevitably have to be on an anticoagulant or you'd end up with a stroke or blocked vessel.

    Now I'm assuming since you said tDCS etc. you mean implanting subdermally, not like intracranial? Intracranial comes with its own issues but isn't as out of reach as some think. Give me a specific application... what are you looking to accomplish here? There are a lot of other answers such as pharmo, transcranial, transdermal, etc.

    As soon as I get caught up on the IR vision project stuff, I really would like to continue on another project that I was working on with ThomasEgi. It was a simple circuit implant. Very small, but incorporating all the basic needs for an implant. I think it would be a good step towards this type of implanted stuff approach to transhumanism. I would argue though that if something doesn't need to be implanted to work... then why? Not at all trying to be a downer, but function and purpose should drive these things in my opinion. If I can wear a tDCS, then why implant it? Perhaps the idea would be to have it active more often, like all the time, or perhaps activate it in certain regions at certain times... Cool yes, but I would still say start with a nice tDCS array doing what it is you want to occur... see if it works out.. and then work towards an implant.

    Anyhow, one thing to consider TGK is the use of accupuncture needles. You can poke em through the skin and they conduct no problem. If you wanted to test the difference between a subdermal vs transdermal electrode, you can totally stick em in your head nearly painlessly and then run some small signal through em. Oh, and don't worry too much about hitting some magick dragon chi point or anything. I really looked into accupuncture... and it unfortunately seems to be entirely entirely bogus. Kind of dissapointing really.

  • One thing to consider is that we might try to create a wearable version of this before trying to make it implantable.  It could, with some effort, be made to cover the 10-20 map of the brain, and still be compact enough to fit into a cap, so that it could be worn nearly constantly.  It would almost be like...a Thinking Cap.

    In fact, this is exactly what I'm trying to accomplish in the near future.  I think it would be much easier to do this wearable version to get the technology perfected, and possibly talk about making it implantable after that.
  • edited October 2013
    In regard to tDCS, how much does electrode placement influence the effects of the device? Also, does the frequency of the current have any effect? 

    Would tDCS have significant or useful affects if used on areas of the brain governing movement and reaction time?

  • @TheGreyKnight: It depends on how much you're varying the placement.  If you stay within a certain region, it shouldn't vary too much, as it's targeting the same function.  If you place the electrodes on a completely different region, then you're essentially targeting a different brain function.  Also, switching anode and cathode will switch whether you're inhibiting or exciting the function in question.

    DC doesn't have any frequency.  If we start talking about CES, then there are theoretical benefits for each frequency, but I don't know if those have been replicated.  My suspicion would be that yes, different frequencies have different effects.

    If you can target the relevant brain regions, it's theoretically possible.  The problem is that if the region is too deep in the brain, tDCS can't really reach it.
  • I was thinking about the viability of using a handful of conductive microdermals around the scalp for tDCS, where you can clip your wiring of choice onto the external ball of the microdermal. Any thoughts on that as a viable option? It wouldn't change anything performance-wise from using something like your Thinking Cap or a headset, but it would mean the electrodes are always in the correct place and you just pick which ones to connect, which at least for me would be a nice convenience.
  • Bumping as this is something i've been thinking about.

    First of all:
    Do not do tDCS via small metal electrodes, the current density will be way too high and you'll get skin burns.

    EEG electrodes are what i've been thinking about - get a bunch of microdermals placed on the standard ten20 points and attach wires to them for use in EEG.

    My problem with this is that i'm absolutely paranoid of infection risks, this is what scared me off going for it:

    That wiki article contains a horror story about someone with forehead microdermals who had an infection eat through the skull - naturally this is not something i'd want to risk.

    On the other hand, having the exact same placement every single time would be extremely reliable for training an EEG-based BCI.

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