Drug and behavioral addictions are characterized by focused pursuit of a single reward above all others. Excessive motivation to pursue reward leads to persistent addictive-like decisions that often undermine an individual’s best interests, and prevail despite adverse consequences. The amygdala plays a key role in reward processing and generating motivation. In the following studies, we explored how optogenetic stimulation of the central amygdala (CeA) modulates decision-making and reward choice, causing specific rewards to be almost compulsively preferred in manners that model many of the DSM criteria for addiction. Rats were trained to choose between a reward paired with CeA laser stimulation or an otherwise unpaired identical or alternative reward. Rats developed a nearly exclusive preference for the CeA laser-paired reward over the unpaired reward. This was true whether the reward was a sucrose pellet or an infusion of cocaine. For sucrose, this preference persisted even when a much larger sucrose reward was offered as an alternative, or when the preferred reward was paired with an electric footshock. CeA laser stimulation also produced persistent pursuit of a flavored reward paired with conditioned taste aversion. For cocaine, CeA laser stimulation produced an escalation of cocaine intake, and compulsive nibbling of the nose port paired with laser-associated cocaine, as though seeking more. For both cocaine and sucrose, CeA stimulation dramatically increased an animal’s motivation for the laser-paired reward over an otherwise identical unpaired reward. In each case, these effects were not the consequence of any independently rewarding properties of optogenetic activation of the CeA alone. These findings suggest that the CeA is involved with assigning increasing value to reward and directing decision-making by generating narrowly focused motivation to seek out reward that may persist in the face of more rewarding alternatives and adverse consequences.

Venue: Venables A-wing Briefing Room, The Open University, Walton Hall, Milton Keynes

Please email questions for the speaker either before or during the event to christopher.heath@open.ac.uk