Effort-Based Decision Making in the rat: An [18F]Fluorodeoxyglucose Micro Positron Emission Tomography Study

Abstract

Decision making refers to the process by which subjects choose between competing courses of action based on the expected costs and benefits of their consequences. Lesion studies in rats suggest that the anterior cingulate cortex and the nucleus accumbens are key structures of a neural system that subserves effort-based decision making. Little is known about brain activation associated with effortbased decisions in intact rats. Using an open hypothesis approach, we used 2-deoxy-2[ 18 F]fluoro-D-glucose positron emission tomography (FDG-PET) to assess regional metabolic changes in two conditions of an effort-based decision making task. In the "same effort" condition, male rats could choose between two response options associated with the same effort but different reward sizes, i.e., decision making was simply a function of reward size. By contrast, in the "different effort" condition, an integration of different efforts and reward sizes associated with the two response options was necessary before making a decision. Separate PET scans were performed from each condition. Subtractive analysis revealed that metabolic activity was increased in the different effort relative to the same effort condition in the left anterior cingulate, left orbitofrontal and prelimbic cortex region. Metabolic activity was decreased in the infralimbic cortex and septum region. Our findings suggest that making decisions on how much effort to invest to obtain greater rewards evokes changes of metabolic activity in multiple brain areas associated with cognitive, limbic, motor and autonomic functions. This study demonstrates that FDG-PET provides a tool to determine in rats regional brain metabolic activity in cognitive tasks.

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

“…In non-human primates, ACC neurons preferentially track action-outcome vs stimulus-outcome associations (Luk and Wallis, 2013) and appear to encode the subjective sensitivity to reward value following its delivery (Cai and PadoaSchioppa, 2012); this is in contrast to BLA neurons which, as mentioned above, likely represent the subjective value of given options before reward delivery. In rats, the ACC shows greater metabolic demands when integrating effort costs and reward magnitude vs when effort costs are held constant and only reward magnitude varies (Endepols et al, 2010). Similarly in humans, functional imaging studies suggest that ACC activity at choice and feedback correlates with the option that maximizes reward over the long term (Boorman et al, 2013), and ACC activation is greater when rejecting highly valued options vs rejecting less preferred options (Izuma et al, 2010).…”

SPECT-imaging of activity-dependent changes in regional cerebral blood flow induced by electrical and optogenetic self-stimulation in mice

“…An unpaired t-test was made when comparing animals in the combined group (mfb-microstim plus vta-optostim) under self-stimulation versus no-stimulation conditions. Following previous studies in small-animal radionuclide imaging (Endepols et al, 2010;Marx et al, 2012;Thanos et al, 2013;Wyckhuys et al, 2010) uncorrected p-values were used.…”

Profiling coping strategies in male and female rats: Potential neurobehavioral markers of increased resilience to depressive symptoms

“…The anterior cingulate and medial prefrontal cortical areas have been implicated in the detection of environmental parameters associated with the prediction error (Ragozzino and Rozman, 2007; Rushworth and Behrens, 2008; Matsumoto and Tanaka, 2004; Alexander and Brown, 2011). Additionally, the insular cortex has been associated with processing the negative consequences associated with prediction errors–likely motivating the animal to avoid the prediction error in the future (Endepols et al, 2010) as well as promoting adaptive decisions in the uncertainty context (Rebola et al, 2012). Another cortical area, the retrosplenial cortex, is involved in the initiation of behavioral shifts necessary to complete tasks involving the balancing of emotional processing when completing demanding cognitive tasks (Vann et al, 2009).…”