sentences:  TMS research in animal studies is limited due to its early FDA approval for treament-resistant depression, limiting development of animal specific magnetic coils.Nexstim obtained 510(k) FDA clearance for the assessment of the primary motor cortex for pre-procedural planning in December 2009 and for neurosurgical planning in June 2011.In 2008, the US Food and Drug Administration authorized the use of rTMS as a treatment for depression that has not improved with other measures.