Frontal cortex as the central executive of working memory: time to revise our view

For historical reasons (Bianchi, 1895; Harlow, 1968; Luria, 1966; Shallice, 1982), a specific link between the central executive of working memory and the frontal cortex was originally suggested by Baddeley (1986). This review discusses the evidence against such a univocal link. Two executive processes investigated in neuropsychology are discussed: inhibition (WCST, Stroop, proactive interference, go-no go, Stop signal and the Hayling test) and dual-task management. The evidence reviewed demonstrates (i) that executive processes involve links between different brain areas, not exclusively with the frontal cortex, (ii) that patients with no evidence of frontal damage present with executive deficits, and (iii) that patients with frontal lesions do not always show executive deficits. In conclusion, this review suggests that it is time for a more dynamic and flexible view of the neural substrate of executive processes to be considered. It also confirms, as recently suggested by Baddeley (1996, 1998a, 1998b), that the study of frontal patients cannot be used as a primary source of evidence to understand CE functions.