A low-cost configurable multichannel cortical stimulator prototype

The recording and decoding of intracranial neural signals for brain-computer interfaces (BCIs) and neural prosthetics is rapidly evolving. These devices have the objective of augmentation and restoration of lost or impaired function for the disabled. While much work has been done in terms of electrical stimulation of muscles, nerves, and the cochlea for prosthetics, comparatively little work has been done to explore the possibility of direct cortical stimulation of the human brain. It has been shown that simple bipolar, biphasic cortical stimulation can induce a wide range of sensory percepts (i.e., visual, auditory, and tactile sensations). It is envisioned that more sophisticated multichannel stimulation using configurable waveforms may produce predictable and controllable percepts, thus paving the way for the next generation of neural prosthetics. Such sophisticated stimulation could be useful in future bi-directional BCIs, which would allow the user to control a device and receive feedback via the same neural interface, e.g., control and proprioception in a prosthetic limb. This paper presents the preliminary design of an 8-channel configurable cortical stimulator prototype based on the compact and low-cost Raspberry Pi® single-board computer. Promising results from initial non-tissue tests are shown.