Implications of shared motor and perceptual activations on the sensorimotor cortex for neuroprosthetic decoding

Area of Science:

• Neuroscience
• Biomedical Engineering
• Rehabilitation Technology

Background:

• Neuroprostheses aim to restore communication for individuals with paralysis by decoding speech motor movements from the sensorimotor cortex (SMC).
• The SMC is involved in both motor control and perceptual processing (visual, auditory), raising questions about potential interference with speech decoding.
• Understanding shared neural activations is critical for developing reliable speech neuroprostheses for daily activities like reading and listening.

Purpose of the Study:

• To develop and evaluate an online electrocorticography (ECoG)-based speech-decoding system for individuals with vocal-tract paralysis.
• To assess the system's accuracy and specificity during common daily tasks, including reading and listening.
• To investigate the neural characteristics and spatial distribution of attempted speech, reading, and listening responses in the SMC.

Main Methods:

• Developed an online ECoG-based speech-decoding system in two participants with anarthria.
• Tested the system's performance during 63.2 minutes of attempted speech and perceptual tasks.
• Conducted offline analysis of spectrotemporal characteristics and spatial distribution of neural responses.

Main Results:

• The speech-decoding system demonstrated zero false-positive activations, maintaining high accuracy and specificity to volitional speech attempts.
• Shared neural populations responding to attempted speech, listening, and reading were identified, primarily in the middle precentral gyrus.
• These shared populations utilized distinct neural representations with differentiable spectrotemporal responses, suggesting a role in speech-motor planning.

Conclusions:

• The developed decoding framework enables speech neuroprostheses to maintain specificity to volitional speech during daily activities.
• This research advances the understanding of how shared perceptual and motor activity in the SMC is managed by neuroprosthetic systems.
• Reliable speech neuroprostheses that retain specificity during everyday tasks are essential for improving the quality of life for individuals with communication impairments.