Final Report Summary - ADDICTIONCIRCUITS (Drug addiction: molecular changes in reward and aversion circuits)
Our affective and motivational state is important for our decisions, actions and quality of life. Many pathological conditions affect this state. For example, addictive drugs hyperactivate the reward system and trigger a strong motivation for continued drug intake, whereas many somatic and psychiatric diseases lead to an aversive state, characterized by loss of motivation. We have studied specific neural circuits and mechanisms underlying aversion and reward with a particular focus on sickness-induced aversion and drug addiction. We identified a pathway by which inflammation induces feelings of discomfort and aversion. This pathway involves prostaglandins and in the end leads to a dampened signalling in the dopaminergic reward system. We have also identified a mechanism important for pain-induced discomfort and characterized parts of the neurotransmittors essential for aversive signalling on a more general level. Finally we have found an important contribution of cholinergic signalling in the reward system for addiction-like behaviors in mice.