Basolateral amygdala supports the maintenance of value and effortful choice of a preferred option

• Published in: The European journal of neuroscience 2017-02, Vol.45 (3), p.388-397
• Main Authors: Hart, Evan E., Izquierdo, Alicia, Dalley, Jeffrey
• Format: Article
• Language: English
• Subjects: Amygdala; Amygdala - drug effects; Amygdala - physiology; Animals; Appetite loss; Appetitive behavior; Baclofen; Baclofen - pharmacology; Cannulae; Choice Behavior; cingulate cortex; cost‐benefit; devaluation; food preference; Food preferences; GABA-B Receptor Agonists - pharmacology; Male; Motivation; Muscimol; Muscimol - pharmacology; Pellets; progressive ratio; Rats; Rats, Long-Evans; Reward; Rodents; Satiety; Sucrose
• ISSN: 0953-816X; 1460-9568
• DOI: 10.1111/ejn.13497

The basolateral amygdala (BLA) is known to be involved in appetitive behavior, yet its role in cost‐benefit choice of qualitatively different rewards (more/less preferred), beyond magnitude differences (larger/smaller), is poorly understood. We assessed the effects of BLA inactivations on effortful choice behavior. Rats were implanted with cannulae in BLA and trained to stable lever pressing for sucrose pellets on a progressive ratio schedule. Rats were then introduced to a choice: chow was concurrently available while they could work for the preferred sucrose pellets. Rats were infused with either vehicle control (aCSF) or baclofen/muscimol prior to test. BLA inactivations produced a significant decrease in lever presses for sucrose pellets compared to vehicle, and chow consumption was unaffected. Inactivation had no effect on sucrose pellet preference when both options were freely available. Critically, when lab chow was not concurrently available, BLA inactivations had no effect on the number of lever presses for sucrose pellets, indicating that primary motivation in the absence of choice remains intact with BLA offline. After a test under specific satiety for sucrose pellets, BLA inactivation rendered animals less sensitive to devaluation relative to control. The effects of BLA inactivations in our task are not mediated by decreased appetite, an inability to perform the task, a change in food preference, or decrements in primary motivation. Taken together, BLA supports the specific value and effortful choice of a preferred option. The basolateral amygdala (BLA) is involved in appetitive behavior, yet its role in choice of qualitatively different rewards is not well understood. Rats could lever press under a progressive ratio schedule for preferred sucrose pellets while chow was concurrently and freely available. In the absence of free chow, BLA inactivation had no effect on lever pressing for sucrose pellets. However, BLA was required to maintain the specific value and the relative choice of the preferred option.