**3. Equipment**

There are several companies producing TMS-related equipment. The basic requirements of TMS service include a transcranial magnetic stimulator and coils. The examples of stimulators and coils are shown in **Figures 2** and **3** [11, 12]. Circular coils are the basic type of coils. Figure-of-eight coils, or also known as butterfly coils, consist of two sets of coils arranged in a figure-of-eight fashion to make the strength of the magnetic field generated more focused when compared with traditional circular coils [13]. They are commonly used for treatment. **Figure 4** shows the magnetic field strength induced by circular coil and figure-of-eight coil, respectively. Double-cone coil has two large cup-shaped windings positioned side by side. It is used

#### **Figure 1.** *TMS machine invented by Dr. Anthony Barker [4].*

*Transcranial Magnetic Stimulation, Connectome and Its Clinical Applications DOI: http://dx.doi.org/10.5772/intechopen.109963*

**Figure 2.** *Example of a transcranial magnetic stimulator [11].*

**Figure 3.** *Different types of commonly used coils [12].*

to stimulate deep-seated structure. H-coil is a special designed coil that is also used to stimulate deep seated target. Apart from the appearance of the coils, treatment coils may also be equipped with specific cooling system for heat dissipation. Heat dissipation is particularly important in more aggressive treatment protocol like theta burst stimulation (TBS) protocol. Liquid cooling system and forced-air cooling system are the commonest cooling systems employed.

Some adjuncts can be used during TMS. Devices recording motor-evoked potential and electroencephalography (EEG) are frequently utilized. For navigated TMS (nTMS), sensor, localizers and software for MRI navigation are essential components on top of the basic requirements.

**Figure 4.** *Magnetic field strength induced by circular coil and figure-of-eight coil, respectively [13].*

**Figure 5.** *Mechanism of action for TMS [13].*
