Experimental conditions at a glance
| Experimental (change) condition | Pulse | Stimulus levels | Trials* | Participants | |||
|---|---|---|---|---|---|---|---|
| Rate (Hz) | Amplitude (μm) | Width (ms) | Yes | No | |||
| Stimulus Range I | Reference stimulus: 90-Hz pulse rate, 5.882-ms pulse width, 40-μm amplitude | ||||||
| Pulse shape | |||||||
| Iso-feature-line a | 90 | 40 | 5.882–4.167 | 14 | 420 | 420 | 10 |
| Iso-feature-line b | 40–33.6 | ||||||
| Iso-feature-line c | 40–31.9 | ||||||
| Iso-feature-line d | 40–28.3 | ||||||
| Iso-feature-line e | 40–23.9 | ||||||
| Iso-feature-line f | 40–22.4 | ||||||
| Iso-feature-line g | 40–20 | ||||||
| Pulse rate | 90–135 | 40 | 5.882 | 9 | 270 | 270 | 9 |
| Pulse rate-and-shape | |||||||
| Iso-feature-line d’ | 105 | 40–28.3 | 5.882–4.167 | 14 | 420 | 420 | 9 |
| Iso-feature-line d’’ | 33.5–24.5 | ||||||
| Stimulus Range II | Reference stimulus: 30-Hz pulse rate, 28.571-ms pulse width, 100-μm amplitude | ||||||
| Pulse shape | |||||||
| Iso-feature-line a | 30 | 100 | 28.571–15.385 | 10 | 300 | 300 | 10 |
| Iso-feature-line b | 100–74.3 | ||||||
| Iso-feature-line c | 100–65.7 | ||||||
| Iso-feature-line d | 100–52.8 | ||||||
| Iso-feature-line e | 100–40 | ||||||
| Iso-feature-line f | 100–35.7 | ||||||
| Iso-feature-line g | 100–29.3 | ||||||
Within the stimulus Range I, the reference stimulus was identical for the pulse shape change, pulse rate change, and pulse rate and shape change experimental conditions; in the stimulus Range II, only pulse shape change conditions were implemented, which all had the same reference stimulus. The values across the table for each condition refers to the comparison stimulus (i.e., the “yes” change trials), which were 500 ms long; in the no-change trials, the reference stimulus is presented for the complete stimulus duration (i.e., 1000 ms). *Total change trials can be calculated by multiplying 30 to the number of stimulus levels; equal number of no-change trials were presented during each experimental condition session.
A comparison of performance between pulse rate change and pulse shape change (iso-feature-line d) is shown in Figure 2. A comparison of performance between pulse shape change (iso-feature-line d) and pulse rate-and-shape change (iso-feature-lines d’, d’’) is shown in Figure 3. A comparison of performance between pulse shape change (all iso-feature-lines a–g) in stimulus Ranges I and II, is shown in Figure 4.