Figure 1.

Experimental setup. A: three 4 × 8-electrode Blackrock arrays (photograph) were implanted into the C6, C7, and C8 dorsal root ganglia (DRG) of monkey M, and four 8-contact Modular Bionics probes (not pictured) were implanted in the C7 and C8 DRG of monkey B. B: seven textures were used as tactile stimuli: three natural textures (sandpaper, cotton, and silicone) and four synthetic textures (evenly spaced raised dots). The colored dots next to the name of each texture are the color that will be used to represent that texture in all of the figures. C: each texture was attached to a force probe containing motion tracking markers and a force transducer. The force probe was brushed over different regions of the finger-pads and palm while neural responses were recorded. Fx, shear force in direction of stimulus movement; Fy, shear force orthogonal to stimulus movement; Fz, normal force.