Kewl new TDCs device plans

I have the most basic device - 2 resistors, a regulator & a battery. But http://www.diytdcs.com/ has discovered a nice little circuit with ramping (via a potentiometer) and an analog meter.


I would prefer auto ramping with on/off and a digital meter but for now I will build this new circuit.

I will build this as an intermediate device until I design a proper digital one with a micro controller.

Anti Humour - Killed by a 9 volt Battery

From: http://www.darwinawards.com/darwin/darwin1999-50.html

Resistance is Futile

(1999) A US Navy safety publication describes injuries incurred while doing don't's. One page described the fate of a sailor playing with a multimeter in an unauthorized manner. He was curious about the resistance level of the human body. He had a Simpson 260 multimeter, a small unit powered by a 9-volt battery. That may not seem powerful enough to be dangerous… but it can be deadly in the wrong hands.

The sailor took a probe in each hand to measure his bodily resistance from thumb to thumb. But the probes had sharp tips, and in his excitement he pressed his thumbs hard enough against the probes to break the skin. Once the salty conducting fluid known as blood was available, the current from the multimeter travelled right across the sailor's heart, disrupting the electrical regulation of his heartbeat. He died before he could record his Ohms.

The lesson? The Navy issues very few objects which are designed to be stuck into the human body.

August 2000 Dan Wilson elaborates:

I'm a former Navy petty officer, enlisted for six years as an electrician aboard a US Submarine. I got a lot of training. This story was used frequently during my training in the US Navy as an example of what can happen when procedures and safety measures are not followed. I considered the story an urban legend until I found the incident report referenced in the official Navy electrical safety guidelines. I now know it is true.

The actual event is slightly different than described above, and even more deserving of a Darwin award. This sailor stuck the sharpened ends of the probes through his thumbs intentionally. You see, he had just taken a course that taught a critical concept called "internal resistance."

Internal resistance is resistance to electrical power flow that exists inside any power source. It causes the terminal voltage to drop when load (current) increases. You can demonstrate this concept, if you're careful, by monitoring your car battery's terminal voltage, while someone starts up the engine. The reading will be ~13 volts while the engine is off, but during the period where the starter is cranking it will drop to 8-9 volts. The voltage drop is due to the internal resistance of the battery.

This sailor, like all other electricians in training, had already been through a safety class in which one of the excercises is to measure your body's resistance by simply holding the probes between your fingertips. (Most people read 500Kohms to 2Mohms.) Evidently, adding information from the internal resistance class, this sailor wanted to determine his own body's "internal resistance.". So he intentionally pushed the sharpened probe tips through the skin to elimate the rather high skin resistance and get only the "internal resistance". This, of course, caused his death.

How, you might ask, with only a 9V battery? Easy. One of the "rules of thumb" that the Navy teaches is the 1-10-100 rule of current. This rule states that 1mA of current through the human body can be felt, 10mA of current is sufficient to make muscles contract to the point where you cannot let go of a power source, and 100mA is sufficient to stop the heart. Let's look at Ohm's law. Ohm's law (for DC systems - I will not discuss AC here) is written as E=IR, where E is voltage in volts, I is current in Amps, and R is resistance in Ohms.

When we did the experiment in the electrical safety class to determine our body's resistance, we found a resistance of 500K Ohms. Using 9V and 500K Ohms in the equation, we come up with a current of 18 microAmps, below the "feel" threshold of 1mA. However, removing the insulation of skin from our curious sailor here, the resistance through the very good conducting electrolytes of the body is sharply lower. Around 100 ohms, in fact, resulting in a current of 90mA - sufficient to stop our sailor's heart and kill him.

As my electrical safety instructor said, "The reason we now have to teach the electrical safety course to all electricians at least twice per year is because some joe was bright enough to be the one person in the world who could figure out how to kill himself with a 9V battery."

Day 7 TDCs Maths Protocol

I just finished the 7th day math reinforcement. So this was my 3rd math training hooked to the electrodes. The session went well with no electrode problems or sensitivity.

I will do the tinnitus session in a day or two.

Cautious Opinion on TDCs

I do not wish to be seen to be encouraging people with no scientific background to perform unsafe experimentation so I am including a link to a cautious blog post below. Despite this many FDA approved CES devices are available to the general public. 


So while this post is clearly discouraging I am including it as a matter of caution rather than vitriol. Personally I think TDCs is safe enough to do at home. But you must have some back ground knowledge.


http://blog.zocdoc.com/can-electrical-stimulation-tdcs-enhance-your-brain-performance-fact-vs-myth/

 While the acute effects of tDCS only last about 75 percent of the time of application (e.g. If you stimulate for 20 minutes, the effects will last only about 15 minutes after the current is removed), any enhanced learning that is achieved during the session could potentially last months, just as learning a task without stimulation would. The difference is that you can potentially acquire that new task (i.e. learn) faster, and better.

For this reason, the task you choose is just as important as the tDCS current. Without a learning task, little is likely to be achieved with electrical stimulation. Similarly, the stimulation has to be in the area of the brain that is performing the task. Stimulation in the wrong part of the brain would have no effect or could potentially impair the task, if you happen to stimulate in an area that negatively regulates the area being used.

Safety is another concern. Most of the studies to date have suggested that tDCS is safe at least in a laboratory setting and for short-term use. The few reported side effects such as itching and headache appear to be mild. However, the safety has not been assessed very rigorously, and the results of long-term and repeated use are unknown. Though the effective voltage used in most of the studies is only around two milliamps, caution must be used to ensure that higher voltages are not accidentally applied.

Needless to say, tDCS should never be tried at home because of these potential risks. Scientists using tDCS in a laboratory setting have the expertise and high-quality equipment to assure the safety of their participants. They also have equipment like EEG and MRI that can help them localize the appropriate brain region for stimulation, as well as the training to understand how and when tDCS could be safe and effective. If you’re curious about tDCS your best bet is to find a local university that studies tDCS and volunteer for an experiment.

I don't encourage Joe Blogg's to read my blog and stick a battery onto his drunk mates head. 

I know enough about Electronics & Neuroscience to do this experiment. I would not ever experiment with neuro magnetics. At 1-2mA I feel its reasonably safe taking the large amount of research data into account. I am also limiting my exposure to the procedure to only four initial sessions per protocol. If I feel its worth it at the end of my foray I may do more sessions.

The good news is this - You are regulating an electrical parameter of your nervous system, the current between certain parts of the brain. So the same protocols can be used for BIOFEEDBACK.

Biofeedback eliminates any risk from the application of electricity. By studying and experimenting with TDCs for some time I hope to progress to using a suitably amplified & isolated Ammeter to regulate the protocols by a more natural & safe means. I certainly do not intend to do TDCs for an extended period of time.


So let me spell it out : I have studied Electronics & Neuroscience for many years - that is why I feel comfortable performing these experiments at home. Also my ultimate objective is to develop biofeedback protocols that are more effective & less invasive than TDCs.


I do not intend to use TDCs for an extended period of time. Maybe for a few months at the most.


Also clearly there are various cognitive trainings that can be taken advantage of while applying TDCs, such as speed reading & photo reading, eidetic training, mental calculation, artistic visualisation and so on. I am interested to see the improvement that TDCs offers in these area's.


I also want to add with respect to the post excerpt above from the other persons blog. 


The objective with TDCs - as with working memory training is "Cognitive Enhancement". 
This does not refer to the short term affect during or immediately after the training. It refers to the training of actual cognitive neurological patterns. 


These patterns are reinforced during TDCs and are long term or permanent. The learning of these patterns does not wear off in 20 minutes. This is why I am using the "curve of forgetting". Neurological patterns can be reinforced permanently or with infrequent retraining if it is done correctly. This is also why Biofeedback is probably a superior approach once an intitial familarization has been established with TDCs.

Session 5 - Further electrode problems above right eye

This was my seventh day reinforcement of the "working memory" protocol. Again I had an issue with the electrode above my right eye. This nerve is sensitive because of a dental abscess in my right upper molar.

Again I could feel a mild but sharp pain in the nerve and see a white flash in my right eye. I removed the electrode and placed a new one slightly to the left by a few mm which resolved the problem.

This time it also happened immediately when I started the device which strongly suggests I need to build a better circuit with current ramping to avoid any micro trauma to the nerves involved.

I will look into that.

So this was an initial distraction. Apart from that the session seemed to go OK. I have seemed to notice an improvement in my cognition over all during the last couple of days but perhaps it is placebo.

Here are photos of the electrode placement...

Tinnitus Protocol will be my Next Experiment

I have had Tinnitus since I was 15. Its really very annoying and of course very easy for me to judge subjectively as I can hear it. I will know unequivocally if TDCs has worked or not in this case.


Unfortunately TDCs does not offer a 100% cure for tinnitus.


I need to spend 2-3 days studying the research papers before I decide upon the electrode placements.


Also thanks to http://www.diytdcs.com for linking to this blog. They have quite a good blog with general information on TDCs. You also will come across www.mindalive.com who sell light and sound devices and have many links to research on TDCs.


You may also come across the goflow device - seriously do you need to shell out $100 when a TDCs device has two resistors and a regulator ?


If you really must buy a device you may as well go the whole hog and get a medical device.

Fourth Session Complete

Did the fourth session & second math session this evening. Nothing to report subjectively. Right electrode site stung a little after fresh scalp shave.

Subjective Observations After Three Sessions

 I will need to do 10 - 20 different protocols over an extended period of time - maybe 4x each or more. I am using the curve of forgetting so I do 2 consecutive days then 7 days and a month later per protocol.

I would expect this to give a noticeable result. Doing a couple of protocols once or twice wont achieve much.

So far I have done 2 working memory sessions and a maths session. 

Today I feel that something has perhaps changed. An event happened that would normally make me very stressed & angry. But it didn't. I remained calm and thoughtful. Rather than worrying I calmly considered my options without negative emotion.

Was this linked to the TDCs ? I don't know but it was not how I would normally respond to the event.

TDCs Circuit Breadboards

The pictures speak for them selves - there is very little to the circuit.

My First TDCs Math Session

I used the online vedic maths software. Prior to the session I shaved my head & fresh disposable ECG electrodes were used on P3 & P4

I did the session for 20 minutes and will repeat tomorrow. There was a mild tingling at the begining. I have not done extensive training with the Vedic Maths software yet so I have no subjective opinion on the experience.

My electrode placements were approximated from illustrations.

The TDCs Math Protocol

The electrode placements for the math protocol are illustrated in a previous post. For this protocol I will be using Vedic Math software.
Vedic Math is a very detailed Indian system of mental calculation. A wonderful skill if you are interested in mathematics. I will be doing basic arithmetic problems initially but with vedic math that means adding very substantial figures rapidly in ones mind.


I will brush up on my technique first then perform the TDCs protocol for 20 minutes.
For this session I will shave my head - which is largely bald anyway.
There are many sources for Vedic Math software and I did an extensive search some time ago. 


A Mental Math trainer you can download is available here http://www.jimmyr.com/blog/Speed_Math_Trainer_Program_126_2006.php


There are other superior applications also but the above will suffice for most people initially.
I dont recommend you do this using normal math techniques - its a waste of time. Best to take advantage of the TDCs to learn advanced mental arithmetic methods.


A better online trainer that is specifically for Vedic Techniques:
http://mastermindvedicmaths.com/vedic.php?pro=2


Once you get a taste for mental calculation it becomes very rewarding.

Electrode effects on second session

An interesting session tonight - first up it seems to work. My N-Back score while not out of the ball park is much easier and faster to progress. There is no doubt of that.  I don't know if its placebo. Plenty of other people have done studies that prove it is not.


What was interesting tonight is the electrodes. I am bald on the front and have very short hair so I wont need foam electrodes - I am using disposable ECG electrodes.


Tonight I shaved the fine hair from the left hemisphere electrode position.  As soon as I switched the device on there was a mild tingly sting at the electrode site.


I was stingy and used one of yesterdays electrodes for the position above my right eye. It had a tiny tear and part way through the session I felt my nerve above my eye in the forehead. At the same time there was a white flash in my right eye. This happened several times and I removed the old electrode and replaced it with a new one.


No harm done but very interesting. I will use fresh electrodes and shave the sites for every session now.

My first TDCs session went fine

My first session went fine - I did the working memory protocol

Subjectively it worked initially very well but them my WM session went to custard

I used the N-Back software off sourceforge Brain Workshop

Really the second half went like a normal session - at first I stomped through 4 levels though - easier than normal.

What was different and important ...

I am an artist and can have a very lucid imagination - well all night I could not sleep - I had 3D images flashing through my mind all night - It actually becomes a pain in the ass if they are not of stuff you want to see but its always a buzz to have vivid visualizations.

So I will do the Working memory session again tonight - tomorrow I will do maths.

I am using the curve of forgetting to determine reinforcement dates.

After that I will try visual stimulation & tinnitus protocols

Curve of Forgetting to Reinforce Conditioning

The Curve of Forgetting describes how we retain or forget information that we learn/memorize. This example is based on memorizing that occurs during a one-hour lecture.

On day one, at the beginning of the lecture, you go in knowing nothing, or 0%, (where the curve starts at the baseline). At the end of the lecture you know 100% of what you know, however well you know it (where the curve rises to its highest point).

By Day 2, if you have done nothing with the information you learned in that lecture, didn't think about it again, read it again, etc. you will have lost 50%-80% of what you learned. Our brains are constantly recording information on a temporary basis: scraps of conversation heard on the sidewalk, what the person in front of you is wearing. Because the information isn't necessary, and it doesn't come up again, our brains dump it all off, along with what was learned in the lecture that you actually do want to hold on to!

By Day 7, we remember even less, and by Day 30, we retain about 2%-3% of the original hour! This nicely coincides with midterm exams, and may account for feeling as if you've never seen this before in your life when you're studying for exams - you may need to actually re-learn it from scratch.

You can change the shape of the curve! A big signal to your brain to hold onto a specific chunk of information is if that information comes up again. When the same thing is repeated, your brain says, "Oh-there it is again, I better keep that." When you are exposed to the same information repeatedly, it takes less and less time to "activate" the information in your long term memory and it becomes easier for you to retrieve the information when you need it.

Here's the formula, and the case for making time to review material: Within 24 hours of getting the information - spend 10 minutes reviewing and you will raise the curve almost to 100% again. A week later (Day 7), it only takes 5 minutes to "reactivate" the same material, and again raise the curve. By Day 30, your brain will only need 2-4 minutes to give you the feedback, "Yup, I know that. Got it."

Often students feel they can't possibly make time for a review session every day in their schedules - they have trouble keeping up as it is. However, this review is an excellent investment of time. If you don't review, you will need to spend 40-50 minutes re-learning each hour of material later - do you have that kind of time? Cramming rarely plants the information in your long term memory where you want it and can access it to do assignments during the term as well as be ready for exams.

Depending on the course load, the general recommendation is to spend half an hour or so every weekday, and 1½ to 2 hours every weekend in review activity. Perhaps you only have time to review 4 or 5 days of the week, and the curve stays at about the mid range. That's OK, it's a lot better than the 2%-3% you would have retained if you hadn't reviewed at all.

Many students are amazed at the difference reviewing regularly makes in how much they understand and how well they understand and retain material. It's worth experimenting for a couple weeks, just to see what difference it makes to you!

TDCs electrode positioning

Anode Electrode Positioning	Cathode Electrode Positioning	Observations	Caveats
Primary Motor cortex (M1)	Supra-Orbital	This is the most used montage. It has been proven that the cortical excitability can be changed up to 40%6 (Figure 6). Anodal stimulation results in neuronal depolarisation and increasing neuronal excitability while cathodal stimulation has opposite results6.	Only one motor cortex is stimulated – might be a problem for bilateral pain syndromes. Also the confounding effect of the supra-orbital electrode needs to be considered.
Primary Motor cortex (M1)	Primary Motor cortex	- Interesting approach when there is a bi-hemispheric imbalance between motor cortices (such as in stroke) - Can be used with two anodal stimulation electrodes (see sixth row), where cathodal electrode is placed in the supraorbital area for instance.	Electrodes might be too close to each other- issue of shunting. A decrease of the area of the electrodes will increase the degree of shunting along the skin 19 Therefore shunting might be related not only to electrode positioning but also to electrode size. The relative resistance of the tissues is dependent upon the electrode position and size- the overall resistance on which the current flows is dependent upon the electrode properties19.
Dorsolateral Prefrontal Cortex (DLPFC)	Supra-Orbital	Most used for DLPFC stimulation – positive results for treatment of depression20 and also chronic pain3.	Only unilateral DLPFC stimulation situation is possible with this montage.
Dorsolateral Prefrontal Cortex	Dorsolateral Prefrontal Cortex	- Interesting approach when there is a bi-hemispheric imbalance. - Can be used for a two anodal stimulation situation (see sixth row), where cathodal electrode is placed in the supraorbital area for instance.	Electrodes might be too close to each other- issue of shunting 19. (Please see second row, fourth column).
Occipital	Vertex	Interesting active control for chronic pain trials or for modulation of visual cortex.	When used as active control, reference electrodes are placed in different locations- problem of comparability between intra- and inter- experimental approaches.
Two anodal electrodes, e.g. both Motor cortices	Supra-Orbital	Simultaneous change in cortical excitability	Transcallosal inhibition might add a confounding factor21
One electrode over a cortical target, e.g. Primary Motor cortex (M1)	Extra-Cranial	Avoid the confounding effect of two electrodes with opposite polarities in the brain7.	Depending on intended target, current distribution might not be optimal and therefore induce ineffective stimulation22

Table 2. Electrode Positioning

Images Of Several Protocol Placements:

Demonstration of 4 typical electrode locations on the skull surface when using tDCS. The four figures illustrate the typical placement of anode and cathode during stimulation of the primary motor cortex (A), somatosensory cortex (B), primary visual cortex (C), anterior language cortex (D). Note that in (C) one electrode is placed at the back of the head (see small image of the head), while the other electrode is placed at the right supra-orbital area. One electrode is placed on the area of the skull covering the target structure and the other electrode is typically placed either over the supraorbital area of the other hemisphere or over the corresponding area of the contralateral hemisphere. Note, that other stimulation positions have been used as well .
Figure d is that used for "Working Memory" enhancement. The Anode is placed on the Dorsolateral prefrontal cortex of the left hisphere, the cathode on the supra orbital above the right eye.

Software for TDCs training

There is a great N-Back program on source forge for working memory training called Brain Workshop

I will use that for the working memory protocol & have been using it anyway

I also will be training with Vedic Math software for mental calculation - this also utilizes working memory but I will use the Math protocols with this software.

As for the protocols them selves there is a great deal of scattered information.

This PDF lists several relevant electrode sites

http://www.mindalive.com/1_0/article%2011.pdf

Great care must be taken in selecting the placement areas and the polarity of the electrodes.

My Transcranial Direct Current Device

This is the circuit I eventually chose to build my device. It cost very little to make.

I tested it on a breadboard first. I would consider this to be a bare minimum circuit.

I stuck it into an old TENS machine case.

My TDCs Experiment

My name is Gareth Morgan Thomas. I am an electronics engineer amongst many things and am interested in cognitive enhancement.

To this end I have built a TDCs device and am awaiting my disposable electrodes which I will have in 2 days.

I will initially use the protocols for math improvement and working memory.

I also want to use drawing and art to improve my visual memory and imagination so I will use TDCs to this end also.

My objective is general intelligence enhancement.

At some point I will test my IQ and then again after various protocols.

I will utilize the curve of forgetting to reinforce the TDCs rather than just using a protocol once.

This blog is to be the journal of my experimentation.