Wireless-controlled cubic neural stimulator for free-moving animals

An electrical stimulator transmitting information into selected neural circuits is a promising approach for neural prostheses or animal robots. However, traditional stimulators are based on rigid printed circuit board (PCB) technology; technological limitations hindered the development of stimulators, especially for experiments involving free-moving subjects. Here we described a small (1.6 × 1.8 × 1.6 cm), lightweight (4 g, including a 100 mA h lithium battery) and multi-channel (eight unipolar or four bipolar biphasic channels) cubic wireless electrical stimulator exploiting flexible PCB technology. In comparison with the traditional stimulator, an appliance of both flexible PCB and cube structure makes it smaller and lighter, and enhances its stability. Stimulation sequences can be constructed with 100 selectable current levels, 40 selectable frequency levels and 20 selectable pulse-width-ratio levels. Moreover, the distance of wireless communication can reach approximately 150 m. Both in vitro and in vivo results have demonstrated functionality of the stimulator. The feasibility of remote pigeon's navigation using the proposed stimulator was successfully verified.