Review of Brain-Machine Interfaces Used in Neural Prosthetics with New Perspective on Somatosensory Feedback through Method of Signal Breakdown

Table 1

Skin in the native hand contains multiple types of low-threshold mechanoreceptors that contribute to tactile sensation. This table lists physiological characteristics and response properties from four canonical sensory mechanoreceptor afferents that could be utilized to process signals for sensory feedback. The optimal stimulus is the stimulus shown to result in the response shown. Table values adapted from [12, 13].

Receptor	Optimal stimulus	Response properties	Frequency range	Sensitivity	Receptor field size
SA I Merkel disk	Indentation, points, curvature		0–100 Hz	5 Hz	9 mm^2
SA II Ruffini ending	Skin stretch, hand proprioception		0-? Hz	0.5 Hz	60 mm^2
RA I Meissner corpuscle	Skin movement		1–300 Hz	50 Hz	22 mm^2
RA II Pacinian corpuscle	Vibration		5–1000 Hz	200 Hz	Entire hand/finger