The best replacement for stimuli is stimulus.

The best alternatives to stimuli are rated as following:
★★★★★  stimulus
  internal stimuli
  supraliminal stimuli
  external stimuli
  visual stimuli
  auditory stimuli

Your alternative for stimuli is not listed? Suggest!
Speaking about stimuli, one probably shouldn't forget about stimuli.

Other search terms related to stimuli and their ratings are:
★★★★★ stimuli
You have in mind a companion for stimuli and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of stimuli in all years. Click on graph for more.
stimuli
stimulus
internal stimuli