Amygdala-Prefrontal Cortical Circuitry Regulates Effort-Based Decision Making

Abstract

The basolateral amygdala (BLA) and the anterior cingulate cortex (ACC) region of the prefrontal cortex form an interconnected neural circuit that may mediate certain types of decision-making processes. The present study assessed the role of this pathway in effort-based decision making using a cost-benefit T-maze task. Rats were given a choice of obtaining a high reward by climbing a 30-cm barrier in 1 arm (4 pellets; high-reward [HR] arm) or a small reward in the other arm with no barrier (2 pellets; low-reward [LR] arm). In Experiment 1, bilateral inactivation of the BLA via infusion of bupivacaine impaired decision making, reducing the preference for the HR arm. This effect was not due to spatial or motor deficits because BLA inactivation did not alter behavior when the amount of effort required to obtain either reward was equalized by placing a 2nd barrier in the LR arm. In Experiment 2, disconnection between the BLA and ACC, entailing a unilateral BLA inactivation combined with a contralateral ACC inactivation also impaired decision making. These data suggest that the serial transfer of information between the BLA and ACC guides response selection when evaluating the value of an expected outcome relative to the costs of performing a particular action.

Dissociable Contributions of Anterior Cingulate Cortex and Basolateral Amygdala on a Rodent Cost/Benefit Decision-Making Task of Cognitive Effort

“…Without intact functioning of the BLA, workers 'slacked off' and slackers 'worked harder', whereas loss of ACC function caused all animals to reduce their choice of high-effort trials. These results are in contrast to physical effort decision-making tasks, where loss of either BLA or ACC decreased choice of high-effort options in rats (Floresco and Ghods-Sharifi, 2007;Walton et al, 2003b). The dissociation of these two regions in this study extended beyond choice: BLA inactivations had no effect on motor impulsivity and lengthened the latency to choose between LR and HR options; conversely, ACC inactivations increased motor impulsivity but had no effect on choice latency.…”

“…Surgery and microinfusion procedures were modeled after Floresco and Ghods-Sharifi (2007) and Ghods-Sharifi et al (2009). When baseline performance was deemed statistically stable (30-35 sessions), animals were implanted with 22-gauge stainless steel guide cannulae (Plastics One; Roanoke, VA, USA) bilaterally into the BLA or ACC using standard stereotaxic techniques.…”

“…Excitotoxic lesions and pharmacological inactivation of either the basolateral nucleus of the amygdala (BLA) or ACC shifts rats' behavior away from high-effort, high-reward (HR) options (GhodsSharifi et al, 2009;Rudebeck et al, 2006b), as does contralateral disconnection of these regions (Floresco and Ghods-Sharifi, 2007). Thus, the BLA and ACC are necessary to overcome aversive work requirements and select the maximally rewarding option, although their unique contributions remain unclear.…”

Intra-accumbens injections of the adenosine A2A agonist CGS 21680 affect effort-related choice behavior in rats

“…Furthermore, studies involving choice behavior have shown that rats administered DA receptor antagonists or rats with accumbens DA depletions reallocate their behavior away from food-reinforced tasks that have high response requirements and instead select less-effortful types of foodseeking behavior (Salamone et al , 1997(Salamone et al , 2003. Some of these studies utilized maze tasks to assess effort-related choice Cousins et al 1996;Denk et al 2005;Floresco et al 2007). In addition, several studies have employed a concurrent fixed ratio 5 (FR5)/chow-feeding procedure .…”

“…Several lines of evidence indicate that, in addition to nucleus accumbens DA, other brain areas and transmitters are involved in effort-related processes, including prefrontal cortex, amygdala, and ventral pallidum (Walton et al 2002(Walton et al , 2003Schweimer et al 2005;Schweimer and Hauber 2006;Floresco and Ghods-Sharifi 2007;Farrar et al 2008). Recent studies also have highlighted the involvement of the purine nucleoside adenosine in this type of function .…”