Transcranial Magnetic Stimulation (TMS) therapy relies on a simple principle: Neurons that fire together, wire together. Just as constantly practicing a free-throw shot in basketball will train those muscles and neurons to fire in just the right way, other parts of our brain will become primed to fire in certain ways when they are repeatedly used.
Research has shown that MRI brain scans of patients with depression consistently show decreased activity in the dorsolateral prefrontal left area of the brain (the top front left side of your brain straight up and to the side from your eye). This part of the brain is highly associated with mood, motivation, and pleasure, which explains why those with depression feel the way they do; the part of their brain that's in charge of those things isn't as active as it should be. If we can help that part of the brain return to normal activity, depressive symptoms will go away.
In TMS therapy, two coils forming a figure eight shape, are placed on the surface of the head. Then, when a current is sent through the coil, it creates a focused magnetic field that extends down into the brain. This magnetic field then interacts with the electrical nature of brain neurons, causing them to fire. The nature of this magnetic field isolates the stimulation to the area of a golf ball, allowing doctors to target just the area that needs help, without affecting other areas in the brain.
This process essentially teaches them how to be active again. Just like with learning a new language or math in school, TMS therapy is most effective when applied each day for short periods of time instead of for a long period of time once of twice.
As we help these neurons repeatedly fire, they eventually learn how to fire properly on their own, and the stimulation from TMS therapy is no longer needed. Unlike, medications, TMS fixes the problem by treating the dysfunction instead of just helping the body cope with the dysfunction. Treatment is short term and the benefits continue beyond the treatment time. The only reported side effects are mild headaches after treatment, and minor hearing damage due to the clicking of the coil right by the ear. It's essentially a workout for your brain, and your brain gets a little tired and sore after the first couple of treatments, just like you would feel sore after your first few workouts at the gym. Just like with working out, these headaches can be minimized by eating well and drinking plenty of water. To avoid any hearing damage, patients simply wear earplugs.