A form of neuromodulation is conveyed from an external source to an interior of the skull to modulate neural activity. One or more apertures are formed through or partially through the skull to provide an interface for neuromodulation delivery. Parameters of one or more states of the brain may be sensed through an interface formed with one or more apertures extending all or part of the way through the skull. A device provides an interface between the exterior of the skull and the brain that includes a channel of a length sufficient to traverse the entire thickness of the skull or at least a part of the thickness of the skull. The channels may be configured for ion conduction of electrical signals, enabling DC or near DC stimulation of target neurons.
