Localization of function all over again.

In this special issue of NeuroImage, five leading groups of investigators of human brain function have addressed a key issue of cerebral cortical functional organization, an issue that has been raised and settled in different ways at different times in the history of the brain sciences. The pendulum has swung from localization in the time of Gall and Spurzheim through Fritsch and Hitzig to equipotentiality in the time of Lashley. What is notable about the five sets of studies in this special issue is their focus on both localization issues in the prefrontal cortex and the interaction between noninvasive studies in humans and experimental research at the cellular level traditionally carried out in nonhuman primates. The cooperation between these fields is an extremely positive development providing stimulation and challenge for both fields. Studies in nonhuman primate models benefit from a testing ground for extrapolating findings and theories to the human condition. And conversely, cellular neurophysiology can provide an experimental testing ground for theories of human cognition based on patterns of areal activation under manipulated behavioral conditions. Indeed, the articles in this issue have been forthright about the limitations of fMRI with respect not only to the issue of spatial resolution but also to the sophistication of experimental and analytic procedures, particularly well exposited in the articles by Nystrom et al. and by Postle et al. in this volume. When the findings from both endeavors concur, science advances. An excellent example of concordance between nonhuman primate and human studies is D’Esposito et al.’s adaptation of the experimental design of Quintana and Fuster (1992). Perhaps because the cognitive operations enforced in the monkey study were easily translated to humans, the results and conclusions of the human study turned out to be congruent not only with Quintana and Fuster but also with a large number of electrophysiological studies in nonhuman primates and also with cognitive and neuropsychological research in humans subjects. When imaging results in cognitive neuroscience can be bolstered by neurophys-