Bilateral Orbital Prefrontal Cortex Lesions in Rhesus Monkeys Disrupt Choices Guided by Both Reward Value and Reward Contingency

Alicia Izquierdo, Robin K. Suda, Elisabeth A. Murray

Journal of Neuroscience • 2004

DOI PMC

Reinforcer Devaluation Task

behavioralrhesus monkey

Objective: Assess monkeys' abilities to alter choices of objects when the value of the underlying food has changed to test whether the orbital prefrontal cortex is necessary for guiding behavior based on expected reward value

Materials & Equipment Checklist

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Gather these items before starting the experiment. Check off items as you prepare.

Materials1

Food reinforcers

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Protocol Steps

Reinforcer Devaluation Task

Monkeys are tested on their ability to alter choices of objects when the value of the underlying food has changed. This task assesses whether monkeys can adjust their behavior based on changes in reward value.

Two separate assessments - one shortly after surgery and another approximately 19 months after surgery

Note: This is the primary experimental task measuring orbital prefrontal cortex function in reward-based decision making

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“a task that assesses the monkeys' abilities to alter choices of objects when the value of the underlying food has changed”

Object Reversal Learning Task

Standard test of flexible stimulus-reward learning where monkeys must learn to reverse their choices based on changing stimulus-reward associations

Note: Comparison task to assess flexible learning abilities

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“a standard test of flexible stimulus-reward learning, namely object reversal learning”

Object Discrimination Learning

Monkeys are tested on acquisition of object discrimination learning problems to assess basic learning abilities

Note: Control task to verify basic learning capacity is intact

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“unimpaired in acquisition of object discrimination learning problems”

Food Preference Test

Monkeys are allowed to choose foods alone among six different foods to assess their ability to assign value to familiar foods

Note: Tests satiety mechanisms and value assignment to foods

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“responded like controls when allowed to choose foods alone, either on a food preference test among six different foods”

Selective Satiation Test

Monkeys are tested after selective satiation to assess their ability to adjust food preferences based on satiety state

Note: Tests whether satiety mechanisms are intact

View evidence from paper

“or after selective satiation”