High-gamma electrocorticography activity represents perceived vibration intensity in human somatosensory cortex

Area of Science:

• Neuroscience
• Biomedical Engineering
• Human-Computer Interaction

Background:

• Haptic feedback is crucial for rehabilitation and brain-computer interfaces (BCIs).
• A key challenge is objectively measuring perceived haptic sensation intensity during real-world use.
• Current methods often rely on subjective user reports or controlled experimental settings.

Purpose of the Study:

• To investigate if neural signals in the somatosensory cortex can represent perceived haptic intensity.
• To explore the relationship between neural activity and subjective haptic perception.
• To determine if this neural representation is independent of stimulation amplitude.

Main Methods:

• Recorded electrocorticography (ECoG) signals from a participant with chronic implants.
• Applied controlled haptic vibrations to the participant's fingertips.
• Analyzed high-gamma (HG) band activity (70-170 Hz) in the somatosensory cortex.
• Correlated HG activity with both vibration amplitude and perceived intensity.

Main Results:

• Perceived haptic vibration intensity was represented in the HG band of the somatosensory cortex.
• Distinct cortical channels corresponded to individual fingers.
• HG activity showed a stronger correlation with perceived intensity (rs = 0.45, p < 10^-6) than with vibration amplitude.
• This neural representation was independent of the stimulation amplitude.

Conclusions:

• High-gamma neural activity in the somatosensory cortex reflects perceived haptic intensity.
• This finding offers a potential method for passively quantifying haptic feedback.
• It could lead to more effective and reliable haptic systems in rehabilitation and BCIs.