Pavlovian Autoshaping

Pavlovian autoshaping (sign-tracking versus goal-tracking) measures individual differences in Pavlovian conditioned approach behavior by presenting a retractable lever-CS that predicts food delivery to an adjacent magazine. Sign-trackers (STs) approach and engage the lever-CS itself, while goal-trackers (GTs) approach the food magazine during CS presentation. This behavioral variation maps onto distinct neurobiological phenotypes: STs exhibit elevated dopamine release in the nucleus accumbens core during CS presentation and show greater incentive salience attribution, while GTs rely more on model-based reward prediction. The ST/GT distinction has emerged as a powerful individual differences framework for addiction vulnerability research.

The Pavlovian Conditioned Approach (PCA) index integrates lever contacts, magazine entries, and their respective latencies into a composite score ranging from -1 (pure goal-tracker) to +1 (pure sign-tracker). Intermediate scores classify subjects as intermediates (IN). Response probability (proportion of trials with lever contact versus magazine entry), contact number, and latency measures contribute independently to the PCA index. The distribution of PCA scores typically shows bimodal or trimodal clustering across outbred populations, enabling phenotype-based group assignments for subsequent addiction-related testing.

ConductMaze controls lever extension/retraction timing, pellet dispenser activation, and simultaneous monitoring of lever contacts and magazine head entries via infrared beam detection. The software computes PCA indices in real time across sessions, classifying subjects into ST, GT, and IN phenotypes using configurable threshold criteria. Trial-by-trial acquisition curves for both lever-directed and magazine-directed behaviors reveal the developmental trajectory of conditioned approach. The platform supports downstream testing of sign-tracker versus goal-tracker subjects in self-administration, reinstatement, or impulsivity paradigms.