 Valence could be assigned a number and treated as if it were measured, but the validity of a measurement based on a subjective report is questionable.Measurement based on observations of facial expressions, using the Facial Action Coding System and microexpressions (see Paul Ekman) or muscle activity detected through facial electromyography, or on modern functional brain imaging may overcome this objection.Emotional valence is represented in right posterior superior temporal sulcus and medial prefrontal cortex.