title: Optogenetic excitation of central amygdala amplifies and narrows incentive motivation to pursue one reward above another.
abstract: Choosing one reward above another is important for achieving adaptive life goals. Yet hijacked into excessive intensity in disorders such as addiction, single-minded pursuit becomes maladaptive. Here, we report that optogenetic channelrhodopsin stimulation of neurons in central nucleus of amygdala (CeA), paired with earning a particular sucrose reward in rats, amplified and narrowed incentive motivation to that single reward target. Therefore, CeA rats chose and intensely pursued only the laser-paired sucrose reward while ignoring an equally good sucrose alternative. In contrast, reward-paired stimulation of basolateral amygdala did not hijack choice. In a separate measure of incentive motivation, CeA stimulation also increased the progressive ratio breakpoint or level of effort exerted to obtain sucrose reward. However, CeA stimulation by itself failed to support behavioral self-stimulation in the absence of any paired external food reward, suggesting that CeA photo-excitation specifically transformed the value of its external reward (rather than adding an internal reinforcement state). Nor did CeA stimulation by itself induce any aversive state that motivated escape. Finally, CeA stimulation also failed to enhance 'liking' reactions elicited by sucrose taste and did not simply increase the general motivation to eat. This pattern suggests that CeA photo-excitation specifically enhances and narrows incentive motivation to pursue an associated external reward at the expense of another comparable reward.
authors.affiliation: Psychology Department, University of Michigan, Ann Arbor, Michigan 48109, and Psychology Department, Wesleyan University, Middletown, Connecticut 06459 mjrobinson@wesleyan.edu.
authors.forename: Mike J F
authors.identifier: http://orcid.org/0000-0002-4028-2167
authors.initials: MJ
authors.lastname: Robinson
authors.affiliation: Psychology Department, University of Michigan, Ann Arbor, Michigan 48109, and.
authors.forename: Shelley M
authors.identifier: http://orcid.org/0000-0003-3926-7741
authors.initials: SM
authors.lastname: Warlow
authors.affiliation: Psychology Department, University of Michigan, Ann Arbor, Michigan 48109, and.
authors.forename: Kent C
authors.identifier: http://orcid.org/0000-0002-6031-2626
authors.initials: KC
authors.lastname: Berridge
mesh_terms: D000818:Animals; D066274:Central Amygdaloid Nucleus / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D009042:Motivation / Q000502:physiology*; D062308:Optogenetics / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward; D012646:Self Administration / Q000379:methods; D013395:Sucrose / Q000008:administration & dosage
chemical_list: D013395:Sucrose
keywords: central amygdala; motivation; optogenetics; reward