Conditioned Place Aversion

Conditioned place aversion (CPA) measures the aversive properties of stimuli by pairing them with a distinct environmental context and quantifying subsequent avoidance of that compartment. Common aversive unconditioned stimuli include lithium chloride (LiCl, inducing visceral malaise), naloxone (precipitating opioid withdrawal), or kappa-opioid agonists (inducing dysphoria). The neural substrates of CPA involve the insular cortex for interoceptive processing of malaise, the central amygdala for negative valence encoding, and the habenula-interpeduncular pathway for aversion signal transmission to midbrain monoamine systems.

The CPA score is calculated as pre-conditioning time in the to-be-paired compartment minus post-conditioning time in that compartment, with positive values indicating aversion-driven avoidance. This is the inverse calculation of CPP, so that positive values always indicate the expected direction of conditioning. The magnitude of aversion can be compared across doses, compounds, and genotypes. Transition counts and latency to first entry into the aversive compartment provide complementary measures of avoidance motivation versus general locomotor changes.

ConductMaze tracks compartment dwell times with identical precision to the CPP protocol, with the scoring polarity inverted for CPA analysis. The software supports automated LiCl injection-to-session timing, ensuring consistent pharmacokinetic profiles across subjects. Compartment avoidance heat maps visualize the spatial distribution of time spent, revealing whether subjects actively avoid the aversive compartment or simply prefer the safe side. The platform generates dose-response CPA curves when multiple aversion doses are tested across cohorts.