An FPGA platform for generation of stimulus triggering based on intracortical spike activity in brain-machine-body interface (BMBI) applications

Brain-machine-body interfaces (BMBIs) aim to create an artificial connection in the nervous system by converting neural activity recorded from one cortical region to electrical stimuli delivered to another cortical region, spinal cord, or muscles in real time. In particular, conditioning-mode BMBIs utilize such activity-dependent stimulation strategies to alter the strength of synaptic efficacy between remote regions of the nervous system and promote functional recovery after injury by exploiting mechanisms underlying neuroplasticity. This paper presents a reconfigurable, field-programmable gate array (FPGA)-based platform that incorporates digital spike discrimination based on user-set thresholding and time-amplitude windowing, as well as decision-making circuitry to generate multichannel stimulation triggers derived from intracortical neural spike activity. The algorithm has been synthesized on a Cyclone II FPGA using Altera´s Quartus II design software and validated with prerecorded intracortical neural spike activity from an anesthetized laboratory rat.