An introduction to neurostimulation
The nervous system consists of the brain, the spinal cord and lots and lots of the nerves that connect throughout the body. Many people refer to the brain as a computer because it both processes and stores all the information delivered to it through the nervous system. But how does this nervous system get going? With a little neurostimulation.
For example… your wife passes you a cup of coffee saying ‘be careful, thats quite warm’. Without actively thinking about, it your hand will delicately and accurately pick up the cup, by the handle, and you take a drink.
This ‘simple’ action happens through the coordination of vision from your eyes and several sources of feed back in your arm and hand – such as the sense of ‘position’ and sense of touch. It also relies on the memory of what coffee is, and how to even hold a cup!
As you take a drink your mouth and lips will open, just the right amount and time, so as not to spill anything. As the temperature sensors on your tongue register something akin to the surface of the sun, you will immediately move the cup away and proceed to cry a little inside. To conclude, your brain stores this entire event in the ‘bank’ of memory, so that next your wife makes the comment of ‘quite warm’ you understand that’s actually a metaphor for approximately 10,000 degrees Celsius.
So although drinking coffee seems simple, there is a whole system working away in the background choreographing the complete process. And that’s just coffee… what about walking or running or playing a musical instrument?
Electricity & the Brain
Another thing that fits quite well with the ‘computer model’ is that the nervous system works through electricity! The actual decision to wiggle your toes starts off in the brain. In the ‘movement area’ a very very small electrical current is generated which zooms down through the spinal cord eventually reaches the muscles in your foot – leading to the aforementioned ‘wiggle’.
Given that this entire process runs off of electrical impulses, it’s not surprising that for years doctors have been using ‘electricity’ to treat problems! That, ladies and gentlemen, is what we call neurostimulation. Using electricity (and occasionally magnets) to make the nervous system better!
Although this all seems a bit sci-fi, don’t forget that a cardiac pacemaker is pretty routine these days and it uses electrical pulses to cause the heart to beat regularly – it’s also been around for over 100 years.
To talk about the actual uses of neuromodulation in detail would make for a very long post, so other than two common examples listed below, we will leave that for another time!
Example 1: Deep Stimulation Stimulation
Deep Brain Stimulation (DBS) is used for treatment of Parkinson’s Disease. (Search on Youtube – the effect of this can be very dramatic). Most people associate PD with tremors, however there are many other symptoms such as stiffness, slow movements and reduction of balance. The aim of neurostimulation in the case of Parkinson’s is not to provide a cure, but to improve the symptoms and hopefully make living with the disease a little easier. In some cases it can lead to a reduction in the amount of medication needed.
Tiny electrodes are placed deep inside the brain, with the main body of the device placed under the skin of the chest. When activated the electrodes stimulate the target area of the brain with a high frequency pulse.
Example 2: Vagus Nerve Stimulation
Vagus Nerve Stimulation (VNS) for epilepsy has been around for about 30 years. Although the device is placed in the chest (like the Parkinson’s treatment) the electrodes only go up as far as the neck. Here they wrap around one of the cranial nerves called the Vagus nerve (AKA Cranial Nerve 10). No brain surgery required. The nerve in the neck acts like a wire and carries the signal up to the brain stem, meaning that the risky surgery is a nice distance from the brain. VNS for epilepsy has shown promising results for difficult epilepsy cases that aren’t responding fully to medication.
In principle these devices are all very similar – they act on the area of the nervous system known to cause a problem and ‘fix’ it with electrical pulses. Also, the devices above are all implants – so require fairly risky surgery to have them fitted.
In the last few years there has been a big shift towards ‘non-invasive’ neurostimulators i.e. devices that don’t need any surgery. One of these stimulators happens to be my area of research at UCSD… so fear not, there will be much much more to discuss on this topic!
Dr Jason McKeown
In a previous life I was a doctor - now I make medical devices.
A lover of all things health and fitness, particularly if linked to neurology, neurophysiology or anything brain related.
Mostly, I write about the neuroscience of weight loss, but occasionally I just give little snippets into my busy life.
I travel a lot. If not in Belfast I’m usually in San Diego. Happy to connect with anyone who is keen to improve their health & wellness!