Experimental Setup:

Results:

Control Group (AB-AB):

• The monkey prefers A over B.
• Block 1: Neuron 1 maps to A, Neuron 2 maps to B
• Block 2: Neuron 1 maps to A, Neuron 2 maps to B

Experimental Group (AB-CD):

• The monkey prefers A over B, C over D.
• Block 1: Neuron 1 maps to A, Neuron 2 maps to B
• Block 2: Neuron 1 maps to C, Neuron 2 maps to D
• Remapping consistent with preference order!
• The neural responses in the AB-CD design was indistinguishable from the control, AB-AB design.

2nd Experimental Group (AB-CA):

• The monkey prefers A over B, C over A.
• Block 1: Neuron 1 maps to A, Neuron 2 maps to B

• Block 2: Neuron 1 maps to C (!), Neuron 2 maps to A

• Remapping consistent with preference order, even when previously preferred option was still available!
• Strong evidence indicating that OFC neurons do not encode sensory features of rewards, but the evaluation of the reward in the context of the current decision.
• OFC neurons seem to be tuned to decision parameters, rather than the specific properties of the goods under consideration.

In relation to ‘cognitive map theory’:

• Cognitive map theory suggests that the OFC constructs internal models of the environment, or ‘task structure’, in order to determine optimal decisions.
• Previously, it was thought that OFC neurons can encode arbitrary variables related to the task.
• However, this study shows that there are constraints to which variables OFC neurons can represent! In this experiment, researchers showed that some neurons only encode more preferred rewards, and vice versa.