The balance between reward and aversion is central to adaptive behavior, yet the neural mechanisms orchestrating this balance remain incompletely understood. Recent progress in behavioral neuroscience suggests that decision-making and emotional regulation are shaped by dynamic interactions between dopaminergic, glutamatergic, and peptidergic signaling systems distributed across cortico-limbic networks.

This study integrates functional neuroimaging, behavioral modeling, and molecular profiling to dissect the reward–aversion circuitry underlying motivated behavior. Using a cohort of 120 healthy adults and 40 individuals with maladaptive reward processing (subclinical addiction and anxiety traits), we applied fMRI with dynamic causal modeling (DCM) and diffusion-weighted tractography to map directed connectivity between the ventral tegmental area (VTA), amygdala, and prefrontal cortex. Concurrent saliva cortisol and blood metabolomics provided peripheral biomarkers of stress-linked modulation.

The data reveal that reward expectancy enhances VTA–prefrontal coupling via dopamine-mediated glutamatergic pathways, while aversive cues increase amygdaloid inhibition of orbitofrontal regions, attenuating behavioral flexibility. Elevated peptide signaling (notably neuropeptide Y and dynorphin) correlated with impaired decision speed and heightened emotional reactivity. Machine learning classifiers achieved 88% accuracy in distinguishing adaptive versus maladaptive responders based on neural–biochemical signatures.

These findings delineate a multi-scale model of behavioral regulation, in which cross-talk between reward and aversion networks predicts individual differences in emotional control and cognitive bias. Targeting neuromodulatory peptides and stress circuits could thus inform new interventions for compulsive and affective disorders.