Devices, methods and systems for transmitting signals through a device located in a blood vessel of an animal for stimulating and/or sensing activity of media proximal to the devices. The media can include tissue and/or fluid. A method of controlling an apparatus in communication with a brain machine interface. The method can include measuring a first neural activity in a first neural area and measuring a second neural activity in a second neural area. The first neural activity can be associated with a first intent. The method can include creating and delivering, via the processor, one or more first control signals to the apparatus upon comparing the second neural activity with the first neural activity, and confirming, based on this comparison, that the second neural activity is associated with the first intent.