FIG. 6.
Effect of vibratory amplitude on spatial modulation. Each trace corresponds to a vibratory frequency. The orientation of the gratings was parallel to the axis of the finger and their spatial period was 6 mm. The intensity levels are expressed in decibels relative to the amplitudes matched for subjective intensity (0dB re: max corresponds to the amplitudes denoted by · · · in Fig. 7). Increasing the stimulus amplitude had no effect on the spatial modulation of SA1 responses. On the other hand, RA modulation decreased with amplitude (NSA = 9, NRA = 5).