Discriminability of Single and Multichannel Intracortical Microstimulation within Somatosensory Cortex

Area of Science:

• Neuroscience
• Biomedical Engineering
• Rehabilitation Robotics

Background:

• Restoring sensory feedback in neuroprosthetic limbs is crucial for improving device control.
• Intracortical microstimulation (ICMS) of the somatosensory cortex offers a promising avenue for delivering this feedback.
• Previous research primarily focused on single-point stimulation for intensity discrimination, neglecting the need for complex, multi-stream sensory encoding.

Purpose of the Study:

• To evaluate the capacity of an awake, behaving non-human primate to discriminate ICMS stimuli delivered across multiple cortical locations.
• To investigate the feasibility of encoding multiple, simultaneous sensory information streams using ICMS for advanced neuroprosthetic applications.

Main Methods:

• Utilized an awake, behaving non-human primate (*Macaca mulatta*) model.
• Delivered serial ICMS on single electrodes to assess discriminability of sensations from distinct cortical sites.
• Implemented trains of multichannel ICMS, synchronized with tactile sensor data, across multiple electrodes.

Main Results:

• Discrimination of multiple ICMS stimuli presents a significant challenge.
• However, discriminable sensory percepts were successfully elicited using both single and multichannel ICMS.
• Stimulation was delivered via electrodes spaced within the somatosensory cortex.

Conclusions:

• The study demonstrates the potential of ICMS for encoding complex sensory information necessary for advanced neuroprosthetic limbs.
• While challenging, multichannel ICMS can evoke distinct sensations, paving the way for more intuitive and functional prosthetic control.