Bottom-up but not Top-down Attention Dominates the Value Representation in the Orbitofrontal Cortex

The orbitofrontal cortex (OFC) is essential for value-based learning and decision making. Understanding the attentional modulation of the representation of value in the OFC provides us key information on its functional roles and links the OFC to other cognitive processes. We examined how top-down and bottom-up attention modulates the value encoding in the OFC. Two macaque monkeys were trained to detect a luminance change at a cued location between a pair of visual stimuli, which were over-trained pictures associated with different amount of juice rewards and, thus, different salience. While the monkeys behavior and the DLPFC neuronal activities indicated that the monkeys actively directed their attention toward the cued location during the task, the OFC neurons value encoding, however, was dominated by the bottom-up attention based on stimulus salience and only reflected the top-down attention weakly. The disassociation between the top-down and bottom-up attention signals in the OFC indicates that the OFC occupies an early stage of value information processing in the brain.