422 replies to this topic

[Absent]

I just put together a ghetto device until I can get some proper parts from radio shack tomorrow.

The resistor I used brought the mA down to 2.7ma. I did 9 minutes, with the anode on the left temple and the cathode over the right eyebrow - connected to the sponges of course.

I had no alligator clips so I had to hold the wires in place the whole time, and this was tiresome. There were times when my left temple felt a slight burning sensation - this was not placebo because as I was trying to relax I would become distracted by the intermittent burning on my temple. Due to me holding the wires there may have been times my hand was in contact with the sponge which could throw results off.

I definitely feel in a different headspace as I am typing this...more spacey. I feel MORE distracted, but I do feel an alteration in my focus. It feels enhanced, but not unified. More chaos in it. Got distracted like 10 times trying to type this and couldn't hit the right keys lol. This probably isn't due to my device, as I know the current is correct, but is probably caused by my technique. My connects were not consistent, I kept interrupting it, and adjusting the sponges, checking my stopwatch, etc.

I'm going to try tomorrow when I get proper parts and so that the connectivity to my forehead can be consistent for 15 minutes straight. I do feel like my mind is quieter, in a good way... though that could also be because I had to sit still when I was doing this, and I was resting my eyes for about 10 minutes.

Will try again tomorrow with better technique and report.

Edited by Siro, 08 May 2013 - 04:01 AM.

[Godof Smallthings]

Just FYI, the safety limit is set to 2 mA. Admittedly I can not give you the rationale behind it, but I would be careful with using 2.7 mA stimulation as less may well be more.

Does anyone have clear data on the reasoning behind 2 mA max as the upper safety limit?

There were times when my left temple felt a slight burning sensation - this was not placebo because as I was trying to relax I would become distracted by the intermittent burning on my temple

This is my experience too, even with proper electrodes (AMREX), and also why I think the suggestion to meditate during tDCS does not work so well; the presence of the electrodes and the burning/tingling makes it difficult to relax to the level required for successful meditation.

[soulfiremage]

They say research shows it is more effective if there is less neuronal activity.

Has anyone tried right pfc a nodal stimulation?

[ATA]

Please read something about tDCS and how to use it /bulid it before using it . Some my notes and links http://brmlab.cz/pro...in_hacking/tdcs

If stimulation is done right way you feel nothing maximali slight tingeling . If you feel burning sensation something is wrong.
Sponge with wire is bad choice the current distrubution good . You need consductive ruber pads inserts and put them into the sponge or you may buld id from polyimide conductive foil (much cheaper)

Current limit is not figed in paxe depend on may things like configuration of electrodes its size matrial almout in any study is recomandet limit 2mA recomandet curremt density is about 50uA max about 80uA/cm2 HD-tdcs use higher current density with smaller electrodes i test about 300uA/cm2 without problem (EEG gel) and 200uA/cm2 with sponges but in sponges is fealing inconsistent and technologi need some improvements.

Use OZ as reference is not very good idea .Depend od its size but may compromise vision .Curent path aslo is not optimal.

Unfortunetly gyrification in prefronatal cortex very vary among the people so its gard targeting right area ( optimalize current path ,use radial or tangental fields)
Witch standart TDCS electrodes you probably target DLPFC but also amyn others areas .

[soulfiremage]

It is quite tricky to be objective about the effects-there may be placebo most definitely. I've avoided "tests" because (life is too short...) I would be simply training for tests and most do not cross over. Even dual n back is heavily questioned as to any potential crossover.

Emotionally I'm perhaps a little calmer, slightly more focused and precise of thought. I've done two 30 minute sessions, reference on right arm, 5x5 cmabove left eye. Second session was a little more to the left. I couldn't be sure of mental effects during stimulation as of course I'm expecting "something" so would get observer effect.

Mental arithmetic like 37x37 whilst driving seemed a little easier and I got it right (1369) - this is a test I do just once a day as I'm not very good at it. It's hardly objective and cannot avoid learning effect.

I don't know why the manual clearly states the need to do nothing during stimulation, I find that a limitation I could live without. Does anyone have any evidence to the contrary? I'm at work so can only search a little bit.

[greyarate]

I don't understand how some of you guys think you are getting an accurate current regulated stimulation using just a 9V battery and some resistors. Taking Ohms law of V=IR, or Current I = Voltage/Resistance. The resistance in that circuit is going to be (connecting wires + resistor + electrode resistance + resistance between the electrodes). Aka the current delievered is going to be heavily dependent on the resistance of and between the electrodes. This could vary quite a bit person to person, if the person was warm/sweating for example skin conductivity would be larger due to the salty nature of sweat. Also when placing both of these electrodes on the forehead as mentioned I would imagine a good chunk of the current could just travel through the skin from electrode to electrode. Electrical current will always take the easiest path after all and I can't imagine a path of skin-bone-brain-bone-skin is easier than skin-skin (especially if wet).

If you actually want to use a specific current level you need to build a current regulated device. One such option was mentioned in this very thread. That uses a special diode to limit the current delivered. Another option is to build a circuit using a constant current source - something like an LM334. With that kind of circuit the voltage delivered would be adjusted automatically by the IC to provide the desired current.

[soulfiremage]

This is my kit: http://www.trans-cra...lation-kit.html

My resistance hovers under 3ohms

[ATA]

3ohms ? probably you ment 3Kohms 3000 ohms

[Absent]

I don't understand how some of you guys think you are getting an accurate current regulated stimulation using just a 9V battery and some resistors. Taking Ohms law of V=IR, or Current I = Voltage/Resistance. The resistance in that circuit is going to be (connecting wires + resistor + electrode resistance + resistance between the electrodes). Aka the current delievered is going to be heavily dependent on the resistance of and between the electrodes. This could vary quite a bit person to person, if the person was warm/sweating for example skin conductivity would be larger due to the salty nature of sweat. Also when placing both of these electrodes on the forehead as mentioned I would imagine a good chunk of the current could just travel through the skin from electrode to electrode. Electrical current will always take the easiest path after all and I can't imagine a path of skin-bone-brain-bone-skin is easier than skin-skin (especially if wet).

If you actually want to use a specific current level you need to build a current regulated device. One such option was mentioned in this very thread. That uses a special diode to limit the current delivered. Another option is to build a circuit using a constant current source - something like an LM334. With that kind of circuit the voltage delivered would be adjusted automatically by the IC to provide the desired current.

Have you ever heard of a little tool called a multi-meter. Can be used to measure current flow.

[soulfiremage]

3ohms ? probably you ment 3Kohms 3000 ohms

Probably. There's a reason I didn't make my own box....

Now can anyone shed some light on right pfc stimulation? I use arm reference as I did not wish to inhibit right pfc at least not yet. I'm after focus, memory yet creativity you see. My piano playing was more varied this morning after left pfc stim.

[greyarate]

Have you ever heard of a little tool called a multi-meter. Can be used to measure current flow.

Sure but this will lead to you having electrodes connected to your head while you change resistors or trim a potentiometer to get the desired current. I have seen a few projects where people got their 2ma or whatever by touching the two electrodes together before application but this would obviously drop after applying to the head. No real danger there as such but people may not be getting the current they think they are if they don't monitor it during the process which makes it difficult for others to repeat the experiment with similar conditions.

The other problem is many cheaper multimeters may not be all that accurate in the range of 1-2mA or may even have a minimum displayed value of 1mA.

[renfr]

Are the effects permanent? I mean if you use tdcs for 1week or 1 month then stop using it is cognition still enhanced.
Is there any tolerance to it?

[formergenius]

So just an update of my tDCS set-up:


Essentially identical to the one I used as referance. Only difference is in the CRD, supposedly some other model but still 1.5mA I was told.
Only problem is, I get a 5.8mA output when I test with a multi-meter. Now I don't know what I'm doing wrong, so perhaps the CRD is too different, my multi-meter is shit, or I fried something by testing it with the meter (closing the circuit)?

I really don't know, I'm shit with electronics. I'm consulting with the electronics store this Friday, but untill then, any advice would be appreciated.

In the meantime: Decided that making electrodes is going to be even more above my abilities, so I've decided to order the Amrax sponge electrodes. However, I can't find any good info on which size to get? I'll do some more research into that, but it would be nice to get some advice on that.

Oh well, if this fails, I have a professional tDCS session planned for next month. I'm just being impatient

I suppose indeed Oz would be to far from the PFC. However, cathodal Oz, and neck/shoulder anode.... wonder what that would do?
Vision altered is exactly what I need.

Edited by formergenius, 08 May 2013 - 07:14 PM.

[greyarate]

Your diode has probably failed if you are reading 5.8mA. Either that or it's not a CRD and is just a normal diode. A regular diode will just act like a short circuit in this case and it will have a forward voltage drop of ~0.7V. If we take V=IR, I=V/R = (12-0.7)/2000 = 5.65mA. Allowing for inaccuracies in the resistor values and the calibration of the multimeter that's pretty much what you are getting.

One way to check this for sure is to set your multimeter to the diode test / beep test mode. This is the mode where the thing beeps when you touch the probes together. Usually has a diode and/or a kind of beep symbol. Take the diode out of the circuit and probe it with the black lead on the side where the black band is and the red lead on the other. It should beep. Now turn the diode around and put the red lead on the side with the black band and the black lead on the other. If it dosen't beep here the diode is probably just a regular diode and not a CRD. If it beeps in both cases it may have been a CRD but is now broken. A diode should only conduct current in one direction hence the test.

Btw I don't think you really need that capacitor in there and I'm pretty sure you have it wired backwards anyway. It's electrolytic and polarized so the side with the light coloured strip needs to go to the negative of the battery. It looks like you have the positive side connected to the resistor going to the negative side of the battery.

[formergenius]

Wow thanks for the detailed response! Let me see.. I have a cheap multimeter, so idk about the beep test... So.. I read the instructions, it says switch to Ohm mode, select "2000 -|>-|-" Hard to explain the symbol, but it's an arrow and a vertical line, with a horizontal line passing thru them. I get a steady 547 reading with the black cathode lead wire connected to the black strip end (cathode) of the diode, and the red lead wire to the other side (anode). Let's see what happens if I switch it around.

So there was a 1 on the screen before connecting anything. I connect, and it still reads 1. Let me check the manual.
"The meter will display the approximate forward voltage drop. If the lead connection is reversed, the meter will display 1; if the diode is shortcircuited, the display shows 0mV."

Hmm.. You can really see why I need tDCS cause I can't extrapolate wheter it is what I need or not from this information.
I presume it means it's a regular diode? I told the guy I needed a CRD, and he didn't know what the hell it was, so I came back with the product number/code, and he gave me this thing and told me it was similar.

Perhaps if I would know the Dutch name, but I translated it literally and he told me Diodes don't regulate current, that's impossible. He does seem rather interested though, when I told him "AND THAT, is where my head goes" so perhaps he'll help me out, with a LM334 build if necessary.

I double-checked when installing, and checked again just now. It is installed correctly. I was told the long pin is positive, the short piece is negative. So accordingly the long pin (anode) is the most forward capacitorwire in the picture, and the short pin (cathode) the other. I checked myself, and there's a "-" on above the short pin.

The capacitor apparently smooths startup and shutdown current.. or something. Makes it build up slowly instead of jolt, is what I understand from it.

Would you know another name for a CRD? Or would you suggest using an LM334 Voltage Regulator?
In that regard, does a CRD regulate current? Because that's what the kind sir at the shop didn't understand.
Again, thanks for your reply.

[greyarate]

It does sound like a normal diode. Chances are your meter does have a beep mode. The symbol you are describing is the circuit symbol for a diode. Sometimes you need to press a select button or similar to make it beep. It's a very useful feature for tracing wires / circuits. Dosen't matter anyway, the fact that you are getting a reading in one direction and not the other and that your meter was reading 5.8mA earlier does suggest that this is a normal diode and not a CRD. Diodes like this are used for things like reverse polarity protection and rectifying signals.

It is true that diodes are not normally used for regulating current hence the reaction you got in the store isn't that surprising. It's actually a pretty novel component and I honestly didn't know it existed until I saw your link! Little wikipedia entry here. You may need to order one of these online.

Tbh if you have come this far you should have no problem building an LM334 based circuit. See the circuit used in the goflow here. You don't need the LED or the bank of switches/resistors. You can just use one resistor to set a fixed current.

[soulfiremage]

Just having a bit of a scary, odd experience here. I was sitting here typing on keybr.com whilst tdcs'ing the right pfc with a left cheek reference.

NO shock or burn or injury or pain....

But as the session ended a sudden shifting of vision/balance or something a flash and a feeling of something throughout my body that is still going on now. I'm typing with both hands to you now, seeing with both eyes, face muscles are ok and coordination etc seems to be normal. Just unsettling.

Now I'm debating whether to quit it for tonight (20 mins of right pfc) or do what I planned which was continue back on the left pfc with a cheek reference again. I'm not in pain or anything - and I know the precautionary principle of course would be stop; except I can't help feeling that I'd be slightly better off doing the left pfc regardless.

Anyone had this odd, body/head/world shifted physical sense before? Nothing mystical I rush to add, just an in the body sensation that was quite a shock.

[formergenius]

greyarate:
Nope, no beep mode, skimmed the manual and the surface of the device thoroughly.
I found a seller on eBay who sells both 1mA and 1.5mA CRD's, the exact same model.
However, there was some confusion on whether they would ship to the Netherlands.
Apparantly only 50+ product orders go outside the UK, but when I try to buy it, it seems as if I can just order it.
I sent them a message inquiring about this contradiction, so I await answers. However, if it would turn out impossible..
Well let's just say I would be very grateful if anyone in the UK would be willing to forward it to me. I'll order an extra CRD for the effort.
But I won't get ahead of myself. Alternative is ordering from Mouser, which is $20 shipping.

Thanks for the info, I'll forward it to the person at the electronics store. Perhaps he would then know what it is. Apparantly it's a "discrete halfgeleider" in Dutch.
Also, the 954 prefix seemed to be from Mouser, and the actual model # is E-152, so that might help finding it.
Regarding the LM334 build: I wouldn't have a problem building it, as it is indeed similarly simple. However, it would require a fuse, which I read was about $20.
Also, if the electrodes would meet, it would blow? Apparantly with a CRD those problems aren't present.
If I were to do the LM334 build, I would go all the way and request the help of the people at the electronics store to build it, Digital mA meter and everything, put neatly into a box, soldering etc.

soulfireimage:
I wouldn't worry too much about it. Was it some kind of phosphene activity? I suppose if it doesn't hurt, it can't hurt.
Also it wouldn't be unnatural for your body to react to your brain being stimilated I suppose. It's all connected essentially. If changes occur in one place, others are effected too. If it was unpleasant/uncomfortable, then you should perhaps reconsider.

[Absent]

formergenius,

Why do you have that set up, seems unnecessarily complicated. Why do you have 3 resistors and a capacitor?

Keep it simple
If you want 2mA:
1 9v Battery + Battery cap connector(cheap)
1 4.5k Ohm Resistor
Pack of Wires
Sponges
Multiple alligator clips - not nessisary but make it easy.


Just have the resistor tied into the anode + path and have the cathode - hooked directly to the other sponge.

For those who don't know, the consensus seems to be anode sponge over left prefrontal coretex/left temple, and the cathode sponge directly above your right eye.

[formergenius]

For various reasons. One of them is to keep voltage spike low; using a 12V battery is safer (from what I've read). Have a look at my source in the previous posts.
The main reason is that I don't know the first thing about electronics, besides that I want to do it right if I connect the stuff to my head. Other than that, there's a limited amount of schematics available online. And, there's no fuse/crd in your version.

Sponge density/conductivity apparantly varies like crazy between type/brand.. I presume making a proper electrode is more complex than the tDCS itself.
Are you referring to the anodal DLPFC stimulation?

[Ben]

This is my kit: http://www.trans-cra...lation-kit.html

My resistance hovers under 3ohms

What's that machine like comfort / ease of use wise? Easy getting the pads into place between uses?

[soulfiremage]

formergenius,

Why do you have that set up, seems unnecessarily complicated. Why do you have 3 resistors and a capacitor?

Keep it simple
If you want 2mA:
1 9v Battery + Battery cap connector(cheap)
1 4.5k Ohm Resistor
Pack of Wires
Sponges
Multiple alligator clips - not nessisary but make it easy.


Just have the resistor tied into the anode + path and have the cathode - hooked directly to the other sponge.

For those who don't know, the consensus seems to be anode sponge over left prefrontal coretex/left temple, and the cathode sponge directly above your right eye.

If one wants some cathodal stimulation of the right pfc of course? I've avoided that so far, using reference electrodes instead on the cheek or upper arm.

I carried on with further left pfc stim last night. No problems there.

I'm moulding a placer to press the pads down more evenly out of poly morph plastic, ill post the results.

This is my kit: http://www.trans-cra...lation-kit.html

My resistance hovers under 3ohms

What's that machine like comfort / ease of use wise? Easy getting the pads into place between uses?

Easy to use. Decent quality. Read the manual on their website, it's fairly clear and decent. Pads are very good, they arrive pre soaked. Unit packed has a strong smell. Import tax is £73! Five days inc bank holiday shipped from Hong Kong.

Expensive but works well and I've done three sessions with it.

[ATA]

to Siro

your advice is not so good is work and its relatively safe but you never know exact current trought the head
aligator clips is not good idea for electronic is unreiable and for sponge is to small area and the corode very fast .

I build my last TDCS for about 5 dolars (multimetr cost about 4-8 i recomad buy it too)

my design is based on LM 334
trimmer to set up current 0.8-2,1 mA

you dont need the fuse in worst case scenario still not harm you maybe you get slight schock or burning and put device off .Its do nothing harmful in the brain the pain is only reaction in the skin (nerve endings)


I higly recomant use constant current source but for infomation intreindividual variability of gyrification , skull thickness may change the effect to specific area even 2x so is very individual find right value .

[Psionic]

Hi ATA! good to see you here again

I would like to ask if you already looked a little into LLLT - low level laser stimulation? It looks like it can remove depression in a few minutes similarly like tDCS does and can be targeted also to LDLPFC (F3). I would like to hear any explanation/comparison to tdcs how a laser works, Lostfalco reported increased energy, clarity and other positive set of experiences. Thanks for your answer..


"Psychological benefits 2 and 4 weeks after a single treatment with near infrared light to the forehead: a pilot study of 10 patients with major depression and anxiety"
http://www.ncbi.nlm....les/PMC2796659/

At 2-weeks post treatment 6 of 10 patients had a remission (a score ≤ 10) on the HAM-D and 7 of 10 achieved this on the HAM-A. Patients experienced highly significant reductions in both HAM-D and HAM-A scores following treatment, with the greatest reductions occurring at 2 weeks. Mean rCBF across hemispheres increased from 0.011 units in the off condition to 0.043 units in the on condition, for a difference of 0.032 (95% CI: -0.016, 0.080) units, though this result did not reach statistical significance. Immediately after treatment the PANAS improved to a significantly greater extent with NIR "on" relative to NIR "off" when a hemisphere with more positive HEV was treated than when one with more negative HEV was treated. We observed no side effects.

[Godof Smallthings]

Just having a bit of a scary, odd experience here. I was sitting here typing on keybr.com whilst tdcs'ing the right pfc with a left cheek reference.

NO shock or burn or injury or pain....

But as the session ended a sudden shifting of vision/balance or something a flash and a feeling of something throughout my body that is still going on now. I'm typing with both hands to you now, seeing with both eyes, face muscles are ok and coordination etc seems to be normal. Just unsettling.

Now I'm debating whether to quit it for tonight (20 mins of right pfc) or do what I planned which was continue back on the left pfc with a cheek reference again. I'm not in pain or anything - and I know the precautionary principle of course would be stop; except I can't help feeling that I'd be slightly better off doing the left pfc regardless.

Anyone had this odd, body/head/world shifted physical sense before? Nothing mystical I rush to add, just an in the body sensation that was quite a shock.

Yes, I experienced exactly what you describe (loss of balance, uneasiness, slight blackout) once when having the anode over the left intraparietal sulcus/superior parietal cortex (a substrate of selective attention) and the cathode over the right inferior parietal cortex (a substrate of orienting). I got the placement idea from this study:

http://www.ncbi.nlm....pubmed/22265704

I thought it sounded like a potentially interesting modality. But something went wrong, and the power ramped up to over 2 mA and then seemed to self-abort, to go back down to 0 again, and then up just above 2 mA again... Luckily the device I am using has an abort button, so I pressed that. Then I checked all wires and connection and tried again with the electrodes in the same position, but the power set to 1.5 mA. The session proceeded normally.

[soulfiremage]

Well I am unsure if I should use right pfc anodal again - my mood today hasn't been that great; yesterday I was pretty good.

The one setup I haven't played with is the more standard left pfc anodal, above right eyebrow cathodal.

[Godof Smallthings]

Well I am unsure if I should use right pfc anodal again - my mood today hasn't been that great; yesterday I was pretty good.

You are not the first person to note negative mood effects from stimulating the right prefrontal cortex. Personally I steer well clear of that.

Left DLPFC anodal and above right eyebrow cathodal has produced no negative effects in me, but then again no pronounced positive effects either.

[formergenius]

Just a quick update here.
I've ordered two 1.5mA CRD's model E-152, they should be here around Monday seeing as I ordered from the UK. Could also be Friday.
I'm still having trouble buying electrodes. Amrex electrodes look perfect for the job, and were also used with the same design I adopted.
However, extensive searches lead to nowhere, and the only place I can buy it from is from the US. Amazon lists 3 weeks dispatch, and all other sites don't send to the Netherlands. I consider making 2"x2" copper plated sponge electrodes. One guy mentioned it in the tDCS subreddit, and it looked decent. Here's a pic:


Now all I have to do is find some copper, which I'm sure they'll have at the electronics store.
Any arguments on the practicality/safety/effectiveness of this idea would be welcome.
It will make this device enitrely homemade, something which would be quite cool, however not a prerequisite.

Cleaning' class='bbc_url' title='External link' rel='nofollow external'>http://sourceforge.net/p/openbrainstim/wiki/Electrodes/']Cleaning sponges typically make poor electrodes because they do not absorb enough water to provide good paths between the metal current distributor and the skin. However, if the considerable pressure is applied to the entire surface of the electrode, cleaning sponges will usually suffice).

→ source (external link)

Hmm it all seems very inconclusive.. I'll continue my search, but in the meantime any ideas for electrode manufacturing are welcome. Preferably step-by-step instructions... Really feel like my cognition has been declining even further lately.

[Absent]

Has anyone experienced any lasting concentration/attention enhancements from stimulating the Left prefrontal coretex? I'm intending to make my setup more durable and reliable today and I'm gonna try again at 2mA to see what my results are.

Also

If anyone is interested I found electrodes on this site.
http://bio-medical.c...CFcyf4AodfDoARw

They have a bunch of other stuff for EEG and other things like that. These electrodes look as if they could work for TDCS though I am not entirely sure.

Edited by Siro, 09 May 2013 - 08:08 PM.

[soulfiremage]

Well I am unsure if I should use right pfc anodal again - my mood today hasn't been that great; yesterday I was pretty good.

You are not the first person to note negative mood effects from stimulating the right prefrontal cortex. Personally I steer well clear of that.

Left DLPFC anodal and above right eyebrow cathodal has produced no negative effects in me, but then again no pronounced positive effects either.

I'm going with left anode right cathode right this minute. I think I may need a smaller cathode pad next time mind. I'm doing 30 mins now and another tomorrow early before I go to work as I've a day on modafinil ahead of me. 9 hours drive plus delivering training.