The amygdala participates in the hedonic or emotional processing of olfactory stimuli. Hedonic Regression methods are used to estimate these price differentials. Nociception is the opposite of beneception and is concerned with consequences and negative hedonic motivation. Hedonic and utilitarian motivation are, however, different between geographic regions. When testing MDMA for medium and high doses, it showed increased hedonic and arousal continuum. Cognitive functions, such as learning and hedonic tone, are impaired with zinc deficiency. Both theorists explain a person's arousal potential in terms of his or her hedonic tone. Characteristic method, relaxes this assumption, based on the usage of fitted prices from hedonic regression. They include contingent valuation, revealed preferences, and hedonic pricing. The hippocampus volume can affect mood, hedonic setpoints, some forms of memory. Emotion is defined as any mental experience with high intensity and high hedonic content. Sosis (2014) has argued the "hedonic treadmill" interpretation of twin studies depends on dubious assumptions. Hedonic adaptation is also relevant to resilience research. Price changes that are due to substitution effects are subject to hedonic quality adjustments. Hedonic adaptation can occur in a variety of ways.