Table 1

Experimental conditions at a glance

Experimental (change)
Rate (Hz)Amplitude
Stimulus Range IReference stimulus:
90-Hz pulse rate, 5.882-ms pulse width, 40-μm amplitude
Pulse shape       
Iso-feature-line a90405.882–4.1671442042010
Iso-feature-line b40–33.6
Iso-feature-line c40–31.9
Iso-feature-line d40–28.3
Iso-feature-line e40–23.9
Iso-feature-line f40–22.4
Iso-feature-line g40–20
Pulse rate90–135405.88292702709
Pulse rate-and-shape       
Iso-feature-line d’10540–28.35.882–4.167144204209
Iso-feature-line d’’33.5–24.5
Stimulus Range IIReference stimulus:
30-Hz pulse rate, 28.571-ms pulse width, 100-μm amplitude
 Pulse shape       
Iso-feature-line a3010028.571–15.3851030030010
Iso-feature-line b100–74.3
Iso-feature-line c100–65.7
Iso-feature-line d100–52.8
Iso-feature-line e100–40
Iso-feature-line f100–35.7
Iso-feature-line g100–29.3
  • 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.