Orbital Prefrontal Cortex

The orbital prefrontal cortex (PF) receives inputs from the olfactory, gustatory, somatosensory, visceral, and visual cortex. It is also interconnected with the amygdala which represents the current value of the resources, given the internal state of the animal. The worth of the different foods is compared in a ‘common currency’ of value. The central sector of the orbital prefrontal cortex uses vision to predict the value of the resources. These changes depend on the extent to which the animal has already become satiated on a particular food, and an interaction between the amygdala and the orbital PF cortex supports the ability to choose a new food, rather than the one on which the animal has become satiated. The lateral sector of the orbital PF cortex supports the ability to change behaviour depending on the outcome.

Dorsal Prefrontal Cortex

The dorsal prefrontal (PF) cortex generates and plans the goals or targets for foveal search and manual foraging. The goals are conditional on the relative recency of prior events and actions, and the connections of areas 9/46 and 46 explain how these areas can support the ability to generate the next goal. Area 9/46 can generate sequences of eye movements because it has visuospatial inputs from the cortex in the intraparietal sulcus and outputs to the frontal eye field and superior colliculus. Area 46 can generate sequences of hand and arm movements because it has inputs from the inferior parietal areas PFG and SII and outputs to the forelimb regions of the premotor areas and thence to the motor cortex. Both areas get timing and order information indirectly from the parietal cortex and hippocampus, and colour and shape information from the ventral prefrontal cortex. Inputs from the orbital prefrontal cortex enable both areas to integrate generate goals in accordance with current needs.

Medial Prefrontal Cortex

In primates, the medial prefrontal cortex (PF) supports sequences of self-generated actions that are performed spontaneously and without external cues to instruct the action that is appropriate. Instead, the actions are performed on the basis of memories of previous events and their outcomes. Inputs from the parahippocampal and hippocampal cortex provide information about the scene or context; and inputs from the amygdala and orbital prefrontal cortex specify the outcomes. In ancestral anthropoids the hippocampal system for navigation was co-opted to support the retrieval of sequences of actions performed with the hand and arm, as in foraging. Outputs to the medial premotor areas influence the choice of actions, either for exploiting current resources or for exploring so as to find new ones. In anthropoids, visual and auditory inputs also convey the actions of conspecifics and predators so that the animal can predict what others are going to do.