What the orbitofrontal cortex does not do

Abstract

The number of papers about the orbitofrontal cortex (OFC) has grown from 1 per month in 1987 to a current rate of over 50 per month. This publication stream has implicated the OFC in nearly every function known to cognitive neuroscience and in most neuropsychiatric diseases. However, new ideas about OFC function are typically based on limited data sets and often ignore or minimize competing ideas or contradictory findings. Yet true progress in our understanding of an area's function comes as much from invalidating existing ideas as proposing new ones. Here we consider the proposed roles for OFC, critically examining the level of support for these claims and highlighting the data that call them into question.

Figure 1

The (lateral) OFC across species. The figure illustrates the OFC in humans and monkeys and the approximate analogous area in rats. The OFC in humans and monkeys is defined as the lateral orbital network (dark blue) and related intermediate areas (light blue) proposed by Price and colleagues. Note that this region is distinct from the medial network, ventromedial prefrontal cortex or what has more recently been called medial OFC. An analogous area has been identified in rats based on connectivity with mediodorsal thalamus, striatum and amygdala, as well as functional criteria.

Figure 2

Taxonomy of proposed OFC functions. The diagram shows possible relationships between the various ideas for orbitofrontal function discussed in the review. Although many of these ideas explain some of the data, they generally fail to explain all of the data. Thus, they are no longer viable freestanding explanations for OFC function. However, as illustrated, they may still be viewed as subfunctions of larger or more general concepts, as they are able to explain subsets of the experimental findings. S-O, stimulus-outcome.