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.

Links

Publisher Full Text

Authors

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

Institution

Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada.

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