Abstract
Normalization is a common cortical computation widely observed in sensory perception, but its importance in perception of reward value and decision making remains largely unknown. We examined (1) whether normalized value signals occur in the orbitofrontal cortex (OFC) and (2) whether changes in behavioral task context influence the normalized representation of value. We record medial OFC (mOFC) single neuron activity in awake-behaving monkeys during a reward-guided lottery task. mOFC neurons signal the relative values of options via a divisive normalization function when animals freely choose between alternatives. The normalization model, however, performed poorly in a variant of the task where only one of the two possible choice options yields a reward and the other was certain not to yield a reward (so called: “forced choice”). The existence of such context-specific value normalization may suggest that the mOFC contributes valuation signals critical for economic decision making when meaningful alternative options are available.
Highlights
Normalization is a common cortical computation widely observed in sensory perception, but its importance in perception of reward value and decision making remains largely unknown
To investigate the direct link between normalized values signals and choice behavior, we focused on the medial orbitofrontal cortex[4,7]. medial OFC (mOFC) is a subdivision of the OFC medial to the medial orbital sulcus (Brodmann’s area 14, 13a, 13b, and 11m), and reciprocally connected to both medial and orbital prefrontal network areas
We found that a common cortical computation, divisive normalization, is implemented in the activity of mOFC neurons representing reward values under these conditions
Summary
Normalization is a common cortical computation widely observed in sensory perception, but its importance in perception of reward value and decision making remains largely unknown. A growing body of evidence indicates that value signals distributed in the brain shape decision-making behavior[1,2,3] Such value signals are especially prominent in the orbital and medial areas of prefrontal cortex[4] and the parietal cortex[5,6] where neural activity represents value information in a diverse array of paradigms[7]. A pioneering finding in orbitofrontal cortex (OFC) indicates that OFC neurons signal the relative values of food items among the alternatives monkeys have recently encountered in a block of trials[16] This finding implies that value signals identified in the OFC may reflect comparative computations such as “divisive normalization”, a common cortical computation for relative information coding proposed to explain nonlinear response properties in sensory cortices[17]. Dashed colored lines indicate where risky and safe options have equal expected value
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
