<qa>  What is the role of predictability of aversive states and conditioning on threat appraisal?One important determinant of contextual fear in both humans and animals is predictability: contextual fear increases when aversive events e.g., electric shock are unpredictable, as opposed to when they are predictable. The present protocol will examine the role of predictability of aversive states and of conditioning on threat appraisal in individuals with mood and anxiety disorders.. 