The benefits of modular brain-machine interface system design

Construction of a brain-machine interface system for neuroprosthetic purposes is at the forefront of many current neural engineering thrusts. Due to recent breakthroughs in device technology and implantation techniques, a basic framework is now sufficiently developed to allow design of systems level interface strategies producing robust, scalable BMIs that adapt quickly to optimize information transfer at the interface. It is useful to develop brain-machine interface systems in a modular fashion, enabling individual component research and development. This study investigates cortical microstimulation as a mode of operation for a sensory encoding component of a brain-machine interface system. It has previously been shown that cortical stimulation of sensory cortical areas produces sensations. In this report we compare behavior induced by either natural auditory cues, or cortical microstimulation of the primary auditory cortex. Five rats were implanted with multi-channel microwire arrays in auditory cortex and required to discriminate cortical microstimulation separated by 1.75 mm. The behavior was compared to auditory discrimination of tones separated by four octaves. The microstimulation resulted in 17% faster response times across the five rats.