Progressive Ratio Protocol

Summary

The test animal is required to respond using the specified lever on a progressively increasing ratio schedule, which may be set to increase after each reward or after multiple rewards, and the subject is rewarded when the ratio is met.

A time out (TO) following the reward can be implemented
The session ends based on time
Correct and incorrect lever presses are counted
- NOTE: Percent correct/incorrect are calculated at the end of the session
Reward is typically a pellet, dipper presentation, or drug infusion
The type of progressive ratio (PR) may be specified as:
- Step: The ratio starts with the start PR value and is incremented by the step value each time the PR frequency is met
- List: Pulls the ratio values from the “X” list, which can be in any sequence
Required Hardware
- Med Associates operant chamber
- Input (lever, nose poke, etc.)
- Stimulus (light, tone generator, etc.)
- Reward delivery (pellet dispenser/receptacle, liquid dipper, etc.)