Creating a neuroprosthesis for active tactile exploration of textures

Area of Science:

• Neuroscience
• Biomedical Engineering
• Sensory Feedback

Background:

• Intracortical microstimulation (ICMS) of the primary somatosensory cortex (S1) can evoke sensations.
• ICMS holds potential for sensorizing prosthetic limbs.
• The ability of ICMS to support active texture exploration remains uninvestigated.

Purpose of the Study:

• To investigate if ICMS can convey information about spatial frequencies during active tactile exploration.
• To determine if monkeys can use ICMS patterns to discriminate virtual textures.

Main Methods:

• Two rhesus monkeys performed a texture discrimination task using a hand avatar controlled by joystick and brain-machine interface.
• Virtual gratings with varying spatial frequencies were presented.
• ICMS pulses were delivered to S1 upon crossing grating ridges, signaling texture information.

Main Results:

• Monkeys successfully discriminated between virtual gratings using ICMS patterns.
• Discrimination accuracy followed Weber's Law, consistent with normal tactile sensation.
• One monkey integrated avatar velocity with ICMS pulses for enhanced texture interpretation.

Conclusions:

• ICMS of S1 can convey spatial frequency information during active tactile exploration.
• This approach could enable neuroprosthetic devices to acquire texture features from natural objects.