Negative Valence System:

A negative valence system is a neural network in the brain’s amygdala that processes and responds to something unpleasant or potentially threatening. These aversive situations (fear, anxiety, loss, trauma) potentially trigger avoidance behaviors or defensive responses. Negative valence system is one of six domains in the Research Domain Criteria (RDoC) framework. In contrast to a positive valence system (handles positive stimuli and rewards), negative valence reacts to harmful stimuli:

• Acute threat causing an immediate fear response to a perceived danger. 
• Potential threat causing anxiety-like state triggered by a potential danger. 
• Sustained threat is a prolonged feeling of threat or unease. 
• Loss is being deprived of something desired. 
• Frustrative non-reward is disappointment in the lack of expected positive outcome.