Discrimination Training
Overview
Discrimination training teaches an animal to respond in the presence of a specific discriminative stimulus (SD) and withhold responding in the presence of a different stimulus (S-delta). For example, a tone might signal that lever presses will be reinforced (SD), while silence signals extinction (S-delta). Successful discrimination is demonstrated when response rates are high during SD and low during S-delta.
This paradigm is foundational for studying stimulus control, attention, and sensory processing. The degree of stimulus control can be quantified using the discrimination ratio (SD responses / total responses). Discrimination training is a prerequisite for many advanced paradigms including reversal learning, conditional discrimination, and interoceptive drug discrimination.
ConductMaze automates discrimination training with configurable stimulus modalities (tone, light, compound), randomized trial sequences with programmable SD/S-delta presentation ratios, and real-time discrimination ratio calculation. The software supports multiple stimulus dimensions and generates psychometric functions for sensory threshold determination.
Trial Flow
Session Start
House light ON, session timer begins
Stimulus Presented
SD or S-delta presented according to randomized sequence
Response Window
Subject responds or withholds during stimulus
Contingency Check
Was stimulus SD and response emitted?
Reinforcer Delivery
Pellet dispensed if correct SD response
Inter-Trial Interval
ITI before next stimulus presentation
Session End
All trials completed or time limit reached
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
| SD Stimulus | enum | Tone 4kHz | Discriminative stimulus signaling reinforcement availability |
| S-delta Stimulus | enum | No Stimulus | Stimulus signaling extinction (no reinforcement) |
| SD Duration | seconds | 30 | Duration of each SD presentation |
| S-delta Duration | seconds | 30 | Duration of each S-delta presentation |
| SD Probability | float | 0.5 | Proportion of trials presenting SD vs. S-delta |
| Number of Trials | integer | 40 | Total SD + S-delta presentations per session |
| Reinforcement Schedule | enum | FR1 | Schedule in effect during SD (FR1, FR5, VI30) |
| ITI Duration | seconds | 10 | Inter-trial interval between stimulus presentations |
Metrics
| Metric | Unit | Description |
|---|---|---|
| Discrimination Ratio | ratio | SD responses / (SD + S-delta responses) — 0.5 = no discrimination, 1.0 = perfect |
| SD Response Rate | presses/min | Rate of responding during SD presentations |
| S-delta Response Rate | presses/min | Rate of responding during S-delta presentations |
| Trials to Criterion | count | Number of trials to reach discrimination criterion (e.g., ratio >= 0.80) |
| Total Reinforcers | count | Total reinforcers earned during SD periods |
| Latency to First SD Response | seconds | Mean time from SD onset to first lever press |
Sample Data
| Block | SD_Rate_ppm | Sdelta_Rate_ppm | Disc_Ratio | Reinforcers | SD_Latency_s |
|---|
Representative data for illustration purposes. Actual values will vary by species, strain, and experimental conditions.
Applications
- 1Sensory processing — determining auditory, visual, or olfactory discrimination thresholds
- 2Drug discrimination — training animals to report interoceptive drug states as discriminative stimuli
- 3Cognitive flexibility — establishing baseline discrimination before reversal learning assessment
- 4Attention research — measuring stimulus control under distracting conditions
- 5Neurotoxicology — detecting subtle sensory deficits from environmental or pharmacological exposure
Related Protocols
Compatible Products
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