TMS stands for transcranial magnetic stimulation. It is a method of using magnets to stimulate the brain through the skull. So what do magnets have to do with the brain and depression? Let’s start with reviewing electrons, they are negatively charged particles. When you see a classical illustration of an atom, electrons are the little things orbiting the nucleus. Electrons are constantly spinning and each one can only spin up or down. Normally in any given time, half the electrons are spinning up and the other half are spinning down. They are in balance and we say this is not magnetic. But when more electrons in one area are all spinning the same direction, then it is magnetic. Around a magnetically charged object is a magnetic field, basically an area of influence where other magnetically charged things can be attracted or repelled.
Now in the brain, brain cells called neurons communicate with each other by using a code on or off. A neuron turns on by producing a burst of electricity. Electricity is due to the movement of electrons. So magnets and electricity are both properties that result from the behavior of electrons. Just like how magnets are surrounded by magnetic fields, electrically charged objects are surrounded by electric fields. These different types of fields can interact with each other.
TMS works because magnetic objects can disrupt electrical fields. Assuming the thoughts running through one’s head are due to very coordinated electrical activity of neurons, what would happen if that was disrupted by a magnetic field? That is the principle behind TMS. A magnetic field can be used to alter the electrical activity in the brain. In those struggling with seizure disorders, TMS can help reduce seizures. In patients who have depression or OCD, TMS can be used to reduce some of the symptoms as well.
What is really positive about TMS is that not only does it allow for various ways to stimulate the brain, but it is non-invasive.