'Theory of mind' and the prefrontal cortex.

Ten years ago there was little knowledge of the functions of the subregions of the human prefrontal cortex (see Fuster, 1989). Over the last 10 years there has been a great change in the amount of information available on the topic. The major source has been functional imaging. The journals now contain a flood of studies on a variety of different types of task where there are significant differences in activation in complex patterns across prefrontal regions. Thus, a process such as episodic memory (autobiographical memory), previously thought not to be strongly related to frontal functions, now seems to involve five, if not six, anterior regions, which are differentially involved depending on subtle variations in the tasks (see Henson et al ., 1999; Lepage et al ., 2001). This suggests that a large number of different types of subprocesses are frontally localized. This flood of information has not, however, led to much closure on the nature of the individual processes involved. The difficulties involved in interpretation may be at least twofold. The first is that the subprocesses involved may be much too abstract to map simply onto the perceptual input or motor output. Secondly, the tasks which activate prefrontal cortex effectively may often involve a number of such subprocesses and …