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

Figure 4

A schematic demonstrating possible filter designs and subsequent processing that could be used to replicate signals from native sensory afferents [13]. The proposed filters for band selection and processing are derived from the properties of sensory afferents from Table 1. SA I signals are shown being replicated by low-pass filtering to 100 Hz; then processing would be applied to replicate as close to 5 Hz steps of sensitivity applicable. RA I shows filtering followed by processing to replicate rapid adaptation as well as the sensitivity levels. RA II signals are shown being replicated by a hypothetical wavelet transform, showing the coefficients for a particular frequency range represented by a wavelet at a particular resolution. Since not much is known about the particular frequency range of SA II signals, it is listed blank. All filter designs and processing methods shown in the figure are hypothetical.