Lumen-traveling biological interface devices and associated methods and systems are described. Lumen-traveling biological interface devices capable of traveling within a body lumen may include a propelling mechanism to produce movement of the lumen-traveling device within the lumen, electrodes or other electromagnetic transducers for detecting biological signals and electrodes, coils or other electromagnetic transducers for delivering electromagnetic stimuli to stimulus responsive tissues. Lumen-traveling biological interface devices may also include additional components such as sensors, an active portion, and/or control circuitry.