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Separate prefrontal-subcortical circuits mediate different components of risk-based decision making.

Abstract

Choosing between smaller, assured rewards or larger, uncertain ones requires reconciliation of competing biases toward more certain or riskier options. We used disconnection and neuroanatomical techniques to reveal that separate, yet interconnected, neural pathways linking the medial prefrontal cortex (PFC), the basolateral amygdala (BLA), and nucleus accumbens (NAc) contribute to these different decision biases in rats. Disrupting communication between the BLA and NAc revealed that this subcortical circuit biases choice toward larger, uncertain rewards on a probabilistic discounting task. In contrast, disconnections between the BLA and PFC increased choice of the Large/Risky option. PFC-NAc disconnections did not affect choice but did increase choice latencies and trial omissions. Neuroanatomical studies confirmed that projection pathways carrying axons from BLA-to-PFC transverse a distinctly different route relative to PFC-to-BLA pathways (via the ventrolateral amydalofugal pathway and ventromedial internal capsule, respectively). We exploited these dissociable axonal pathways to selectively disrupt bottom-up and top-down communication between the BLA and PFC. Subsequent disconnection studies revealed that disruption of top-down (but not bottom-up) information transfer between the medial PFC and BLA increased choice of the larger, riskier option, suggesting that this circuit facilitates tracking of actions and outcomes to temper urges for riskier rewards as they become less profitable. These findings provide novel insight into the dynamic competition between these cortical/subcortical circuits that shape our decision biases and underlie conflicting urges when evaluating options that vary in terms of potential risks and rewards.

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  • Authors

    St Onge JR, Stopper CM, Zahm DS, Floresco SB

    Source

    The Journal of neuroscience : the official journal of the Society for Neuroscience 32:8 2012 Feb 22 pg 2886-99

    MeSH

    Amygdala
    Analysis of Variance
    Animals
    Biotin
    Brain Mapping
    Choice Behavior
    Conditioning, Operant
    Corpus Callosum
    Decision Making
    Dextrans
    Discrimination (Psychology)
    Functional Laterality
    Male
    Neural Pathways
    Nucleus Accumbens
    Phytohemagglutinins
    Prefrontal Cortex
    Probability
    Rats
    Rats, Long-Evans
    Reaction Time
    Reward

    Pub Type(s)

    Journal Article
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    22357871