Encoding and Decoding of Multi-Channel ICMS in Macaque Somatosensory Cortex.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Sensory Feedback Systems

Background:

• Naturalistic control of brain-machine interfaces (BMIs) necessitates artificial proprioception.
• Intracortical microstimulation (ICMS) is a potential method for delivering this artificial sensory feedback.
• Previous research demonstrated ICMS's ability to guide reaching movements in monkeys.

Purpose of the Study:

• To investigate how monkeys decode ICMS signals into target angle and distance.
• To analyze the impact of degraded ICMS feedback on reaching performance.
• To understand the neural decoding strategies employed by the brain for artificial sensory input.

Main Methods:

• A monkey performed a reaching task in a planar workspace with multi-channel ICMS feedback.
• The ICMS feedback was systematically degraded to observe its effect on performance.
• Analysis of error patterns was used to infer the decoding strategy employed by the monkey.

Main Results:

• The monkey's estimate of target direction aligned with a weighted circular-mean strategy.
• This decoding strategy was found to be near-optimal given the ICMS encoding.
• Degraded ICMS feedback led to predictable patterns of errors in target estimation.

Conclusions:

• Animals can efficiently learn to interpret and utilize artificial sensory feedback from ICMS.
• The brain employs effective decoding strategies for integrating ICMS into motor control.
• These findings support the feasibility of using ICMS for naturalistic BMI control.