Disclosed are methods, devices, and systems for inducing neuromodulation by focusing a source of stimulation through a skull/brain interface in the form of an aperture formed in the skull, a naturally occurring fenestration in the skull, or a transcranial channel. Further disclosed are methods, devices, and systems for identifying where to locate skull/brain interfaces, accessories that can be used with the interfaces, and features for controlling stimulation delivered through the interfaces. Multiple indications for the skull/brain interfaces are also disclosed, including diagnosis and treatment of neurological disorders and conditions such as epilepsy, movement disorders, depression, Alzheimer's disease, autism, coma, and pain.