Disclosed herein are devices including a substrate, one or more regions of electrically active material, and optionally at least one electrode. Also disclosed herein are devices or systems including a substrate, one or more regions of electrically active material including muscle cells and neuronal cells, and optionally at least one electrode. In some embodiments, the muscle cells and neuronal cells form one or more neuromuscular junctions at defined locations on the electrically active material. Also disclosed are methods of using the devices and systems for analyzing the effect of compounds on neuronal cell, muscle cell and/or neuromuscular junction activity.
