Supervisory attentional system in patients with focal frontal lesions

The aim of this study was to re-examine the hypothesis of a link between fr ontal cortex and the Supervisory Attentional System (SAS; Shallice, 1988). Contrary to previous studies that examined patients with lesions extending beyond the frontal lobes (Shallice, 1982; Burgess & Shallice, 1996a, 1996b) , SAS or executive functions were evaluated in a group of patients with str ict frontal lesions. Three tasks (Tower of London TOL-, Hayling and Brixton tests) designed to assess specific SAS processes (planning, inhibition and abstraction of logical rules respectively) were administered. In the TOL t est, although frontal patients were slower than control participants, the t wo groups did not differ in their ability to solve problems. Furthermore, t he two groups did not differ in terms of performance in the Hayling and Bri xton tests either. These results are discussed in terms of the SAS model an d are compared to those observed by Shallice (1982) and Burgess & Shallice (1996a, 1996b). Additionally, the issue of the neural subtract of executive functions is addressed.