Transcranial magnetic stimulation (TMS) has been shown to be helpful for many brain disorders such as depression, schizophrenia and migraines. The basic idea behind this technology is using an electromagnetic pulse which passes the skull and generates an electric current inside the brain. Depending on the frequency of the electromagnetic pulse being used, it can either selectively increase or decrease activity in specific brain areas. The main problem with existing TMS is that it can only penetrate about 1-2 cm into the brain, thus it is limited to activating/deactivating areas in the brain's outer layer (the neocortex). Researchers have developed a new deep transcranial magnetic stimulation that can reach further into the brain and inhibit or excite more areas that were previously out of reach. It can reach almost any brain area. Many disorders have brain areas that are either overactive or underactive compared to a normal brain. So this technology will allow scientists to normalize acitivty in disturbed brain regions.

Currently researchers are testing the new deep TMS to treat people who are overweight or obese. To do this they will target the hypothalamus which is a deeper brain structure involved in the various metabolic process of the body. By non-invasively stimulating this area, it may allow people to lose weight without actually having to do any work. Researchers are also using it to improve symptoms in alzhiemer's patients. Alzhiemer's patients often experience a decline in cognitive symptoms over the course of the illness and current treatments leave a lot to be desired. Researchers using deep TMS were able to improve an alzhiemer patient's spatial memory. So this treatment may have some beneficial effects for these people.

Scientists are using this new device to treat the symptoms of depression. They are targeting deeper prefrontal brain areas. They are also targeting regions of the brain that are directly related to reward, like the brain's pleasure center the nucleus accumbens. Often depressed patients experience anhedonia, the inability to experience pleasure. The researchers of deep tms are working on targeting the nucleus accumbens directly to relieve these symptoms. They have already performed studies with this device on over 100 depressed patients and have found deep tms can induce relief from anhedonia in over 50% of them. So this treatment may allow people to get more enjoyment out of life than they normally would. In bipolar depressed patients, they found that 80% of the patients responded to the treatment and 50% of them experienced a significant improvement in depressive symptoms. They have even tested the device on normal healthy volunteers and have claimed that it improved their mood.

Another method to influence the brain is through Deep brain stimulation (DBS). DBS involves implanting a small electrode device deep within the brain. This device can deliver controlled jolts of electricity to inner brain regions. These devices have been used to improve a number of brain disorders. For mood improvement, researchers have targeted an area of the brain called Broadman Area 25. In healthy patients, feelings of extreme sadness are associated with increased activation of the area. In depressed patients this area is overactive and is associated with many of the common symptoms that occur in these patients. So a DBS device implanted in this area can potentially reduce overactivity and improve specific symptoms.

A final method of brain manipulation I want to talk about is called Transcranial direct current stimulation (tDCS). The general idea behind this technology is using a 9 volt battery connected to wires that have sponge electrodes attached to them. You place the sponge electrodes on specific areas of your head and then pass a small 2 milliamp current between them. This may remind people of the more drastic electroconvulsive therapy (ECT), but it is really very different from that procudure. ECT always requires a person to undergo anaesthesia and jolts the brain with 400 to 900 millimps of electricity causing a seizure. ECT profoundly alters the entire brain and can have negative side effects such as memory loss. tDCS, however, is a much more selective tool with fewer negative effects. It really only alters brain activity in the region directly underneath the electrode, so it can have a much more selective targeting ability. It doesn't require anaesthesia and can be done while a person is fully conscious. The sponge electrode connected to the anode part of the battery can increase brain activation, while the sponge electrode connected to the cathode can decrease brain activity underneath it. Transcranial direct current stimulation has several benefits when compared to transcranial magnetic stimulation. For one thing, tDCS does not have the same risk as a causing a seizure so it has an even better safety record than TMS. It is also much less expensive than TMS. tDCS has already been used for a number of different disorders including depression, migraines and schizophrenia. So it may be a cheap and effective alternative to transcranial magnetic stimulation.