Answer :
Final answer:
The mesolimbic pathway (b) is the projection from the VTA to the NA that rewards drug users, playing a central role in the development of addictive behaviors by enhancing the motivation to seek drugs.
Explanation:
The pathway that refers to the projection of dopaminergic neurons from the VTA (Ventral Tegmental Area) to the NA (Nucleus Accumbens) and rewards drug users is known as the mesolimbic pathway. This operational aspect of the dopaminergic system is highly involved in controlling incentive salience, which plays a critical role in the motivational aspect of drug-seeking and drug-taking behaviors. Through processes including sensitisation of incentive salience, the mesolimbic pathway promotes behaviors critical for survival but is also implicated in the pathological pursuit of drug rewards seen in addiction. Furthermore, the mesolimbic dopamine pathway's dysfunction or overactivation by addictive substances can lead to increased motivational drive to consume the drug ('wanting'), without necessarily increasing the pleasure ('liking') derived from drug intake. This divergence explains why, even as the direct pleasure from drug use decreases over time, the motivation to engage in drug-seeking behavior can intensify, contributing to the cycle of addiction.
