Human prefrontal cortex: Processes and representations

The purpose of this chapter is to familiarize you with a variety of contemporary approaches that place the function(s) of the prefrontal cortex in a cognitive context. Obviously, without a context, interpreting findings from single research studies can be difficult. In addition, without a context, it can be difficult to know whether a specific line of research is clearly verifying or rejecting a proposed prefrontal cortex (PFC) function. Finally, as with posterior cerebral cortex functions, it is much easier to see how a particular cognitive component functions within a system if you have an overall context to place that component in. The broad cognitive context that needs to be articulated is one that explains the cognitive commonality between, and the neural mechanisms shared by, higher cognitive functions. Through evolution, humans have acquired “higher” cognitive skills such as language, abstract reasoning, planning, and complex social behavior. Evidence from lesion and neuroimaging research indicates that the PFC mediates the key components composing these higher cognitive skills. A number of theories have been proposed for how the PFC might achieve this. Although many of these theories focus on the types of “processes” that the PFC carries out, an alternative point of view emphasizes the nature of long-term representations stored in the PFC. This chapter reviews both of these approaches although I place more weight on the representational approach, partly because it has been dominated by the process approach to date and partly because it is the view I espouse.