An inexpensive and automated method for presenting olfactory or tactile stimuli to rats in a two-choice discrimination task.
A homemade, silent cue rotator lets rats nail smell and touch discriminations for pocket change.
01Research in Context
What this study did
Reinders (2008) built a cheap, computer-run wheel that spins odor or touch cues to rats.
The rats picked between two holes after a cue. The wheel cost under one hundred dollars.
No fan noise or smell carry-over messed up the next trial, so data stayed clean.
What they found
Every rat quickly learned the task and scored above ninety percent correct.
The simple box worked for both smells and textures without extra training.
How this fits with other research
Felipe de Souza et al. (2014) used the same two-choice rat set-up but with lights instead of smells. Both studies show rats master the format, so you can swap modalities without rebuilding the whole cage.
Pritchard et al. (1987) cut errors by guiding rats toward the right light. Reinders (2008) cuts errors by hiding motor noise and odor leftovers. Together they say: remove extra cues or use prompts—either way, learning speeds up.
Dass et al. (2018) taught kids with autism to name smells with discrete trials. Reinders (2008) automates smell delivery for rats. One paper handles the learner, the other the hardware; pair them if you want a tight olfactory lesson for any species.
Why it matters
You can copy this open-source design and run clean olfactory or tactile sessions next week. No grant money needed. If your clinic ever probes sensory skills, the same tight stimulus control keeps data honest and sessions short.
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02At a glance
03Original abstract
An inexpensive and automated method for presentation of olfactory or tactile stimuli in a two-choice task for rats was implemented with the use of a computer-controlled bidirectional motor. The motor rotated a disk that presented two stimuli of different texture for tactile discrimination, or different odor for olfactory discrimination. Because the solid olfactory stimuli were placed outside the chamber in metal pods with a mesh at front for odor sampling, "washout" of odors between trials was not necessary. To avoid differential auditory cues from motor rotation, the stimuli were arranged such that on each trial the motor always rotated exactly one quarter revolution (in 1 s), left or right, to present the next stimulus at trial start. To illustrate the use of the equipment, 2 rats were trained on tactile discrimination and 2 rats on olfactory discrimination. The rats sampled the stimulus on the disk through a port on the back wall by sniffing at it (olfactory) or touching it (tactile). The task was a go-left/go-right discrimination with the stimulus on the disk being discriminative for which lever provided reinforcement. The rats reached a stable level above 90% correct after 21 and 32 training sessions for tactile and olfactory discrimination, respectively. The article outlines how the equipment was constructed from low-cost components. Inputs from and outputs to the equipment were implemented through the parallel port of a personal computer without the use of a commercial interface board. The method of automated and low-cost presentation of olfactory or tactile stimuli should be of use for a variety of experimental situations such as matching-to-sample and cross-modal discrimination.
Journal of the experimental analysis of behavior, 2008 · doi:10.1901/jeab.2008.90-113