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. Author manuscript; available in PMC: 2022 Jan 1.
Published in final edited form as: Neurosci Biobehav Rev. 2020 Nov 2;120:417–430. doi: 10.1016/j.neubiorev.2020.10.015

Figure 1. Opioid-Induced Plasticity of the Nucleus Accumbens in Relation to Addiction Behavior and Corresponding Affective Experience.

Figure 1.

A schematic depiction of the cycle of addiction in relation to both behavior and affective experience. This figure represents the combination and adaptation of a diagram from Koob and Le Moal (2001) and a diagram by Russell and Feldman Barrett (1999). The circumplex at the center of the figure represents the affective experiences that tend to correspond to the two discrete behavioral phases of addiction: acute involvement with a substance or activity and acute/protracted abstinence. These affective experiences tend to vary with respect to valence (horizontal axis) and intensity (vertical axis), depending on the substance or activity of involvement, the duration of involvement, and the duration of abstinence. The arrows constituting the outer circle represent the cyclical nature of the addictive experience, which coincides with both behavior and affective states. The individual affective states that are indicated within the circumplex are not meant to be exhaustive, but rather representative of the types of states that characterize a given quadrant (e.g., high intensity, negative valence). The paradigms indicated beneath the circumplex refer to the types of experimental designs that correspond to either the involvement or abstinence phase of the addiction cycle. Abbreviations: SA = Self-administration; Sensi = Sensitization; CPP = Conditioned Place Preference; CPA = Conditioned Place Aversion. Beneath these experimental paradigms are the structural plasticity changes that that have been found in the preponderance of studies within the nucleus accumbens.