Proprioceptive stimuli and habit formation: Interresponse time mediated behavior in CD-1 mice

Area of Science:

• Behavioral neuroscience
• Animal behavior

Background:

• Habit formation involves stimulus-response associations, typically using external stimuli.
• Internal proprioceptive cues, like time between responses (interresponse time, IRT), are hypothesized to play a role in habit formation.

Purpose of the Study:

• To investigate if interresponse times (IRTs) function as stimuli controlling sequential choice behavior in mice.
• To determine if mice utilize IRTs to structure their behavior in a two-choice environment.

Main Methods:

• Two experiments were conducted with CD-1 mice using free-operant concurrent variable-interval reinforcement schedules.
• Experiment 1 examined correlations between switch/stay responses and IRT durations.
• Experiment 2 directly reinforced stay/switch responses based on IRT durations, manipulating reinforcement probability.

Main Results:

• Switch and stay responses were differentially correlated with IRT durations in Experiment 1.
• Mice learned to adjust their switching behavior to match reinforcement contingencies based on IRT durations in Experiment 2, regardless of whether the contingency was proportional or inversely proportional.
• All subjects demonstrated IRT-mediated switching behavior.

Conclusions:

• Interresponse times (IRTs) can serve as effective stimuli that control sequential choice behavior in mice.
• This provides the first evidence that IRTs can mediate habit formation and guide complex behavioral sequences.