P.C.Fletcher and R.N.A.Hensor (A)Typical Verbal Maintenance Task Maintenance BHR☐b 阿□丽 (B)Typical Spatial Maintenance Task Maintenance 口可□□0 .□可9□ C)Typical Object Mainte Task Maintenance 回□￥ ✉回☐啊 D)n-back Task 2-hack Task 0-back Task(target=X) BHCRC... BHC RX Alphabetize BHC2H Fig.2 Schematic representation of working memory tasks. vell as the ventral FC in the m WM.Howe ver the differ (Smith and Jonides,1995a.b).The areas more active in the object and spatial information appears more likely to reflect spatial task k were the right VLFC and the right posterior a left-right lateralization than a ventral-dorsal one.spatial tasks (Belger).the spatial task activated the righ arise when the objects are faces.for which obiect tasks tend to produce VLFC activation and spatial tasks DLFCactivation ry si (e.g.Courtney er )One possit that face the partici nsiomainainmoreha1gdhni2o ical studies suggest that face-selective sha pes,which is beyond the normal visuospatial memor neurones are restricted to ventral FC regions (O'Scalaidhe span)(MeCa rthy et al.,1996).Finally,in a study compar etal,19971. esp 【a objec has proved difficul to isolate storage activation was observed in the former and left DLFC in the latter.These studies suggest a role for the dorsal as movements has little support.because activations of frontal854 P. C. Fletcher and R. N. A. Henson Fig. 2 Schematic representation of working memory tasks. task were the left posterior parietal cortex and left inferior well as the ventral FC in the maintenance of information in temporal cortex, a subset of the areas implicated in the study WM. However, the difference between the maintenance of (Smith and Jonides, 1995a, b). The areas more active in the object and spatial information appears more likely to reflect spatial task were the right VLFC and the right posterior a left–right lateralization than a ventral–dorsal one, spatial parietal, right anterior occipital and right premotor cortices. tasks activating the right FC and object tasks activating the In another study comparing spatial and object Sternberg left or bilateral FC. One exception to this pattern appears to tasks (Belger et al., 1998), the spatial task activated the right arise when the objects are faces, for which object tasks tend DLFC, whereas the object task activated bilateral DLFC and to produce VLFC activation and spatial tasks DLFC activation left VLFC. A very similar pattern was reported by McCarthy (e.g. Courtney et al., 1996). One possibility is that faces and colleagues (though in this case the memory task required constitute a special class of visual objects [e.g. the participants to maintain more than 18 different locations/ electrophysiological studies suggest that face-selective FC shapes, which is beyond the normal visuospatial memory neurones are restricted to ventral FC regions (O’Scalaidhe span) (McCarthy et al., 1996). Finally, in a study comparing et al., 1997)]. a spatial delayed response task with an object delayed It has proved difficult to isolate storage from rehearsal matching task (Baker et al., 1996a), greater right DLFC processes in spatial and object maintenance tasks. The hypo￾activation was observed in the former and greater left DLFC thesis that visuospatial rehearsal corresponds to planned eye in the latter. These studies suggest a role for the dorsal as movements has little support, because activations of frontal