Of the different selection methods described in the introduction, space-based attention has been the focus of the vast majority of neuroimaging studies directed at the control network to date. This line of research has been facilitated by a clear understanding of spatial representations within higher-order cortex [5]. Importantly, there is a great amount of overlap between the attention-related activations in frontoparietal cortex RAD001 mw and the topographically organized frontal and parietal areas (see Figure 1 and Box 1), which permits the systematic study of attentional control systems in individual subjects. This approach holds the promise to yield a more complete understanding

of the neural underpinnings of cognitive control processes

related to selective attention. Topographic representations are ubiquitous in the brain and reflect the spatial layout of the sensory receptors; in the case of the visual system, retinal locations are PF-02341066 cost organized in multiple retinotopic maps (Figure 1a,b). The advent of neuroimaging mapping techniques used to define these topographic representations in individual subjects has greatly facilitated the study of functional specialization of visual areas. This approach has been successfully extended in recent years to higher-order cortex. Using a cognitive mapping approach that utilizes periodic memory-guided saccade or spatial attention tasks, topographic organization has been found in a number of areas in parietal and frontal cortex. To date, seven topographically organized areas have been described in bilateral posterior parietal cortex (PPC): six of these areas form

a contiguous band along the intraparietal sulcus (IPS0-IPS5), and one area extends medially into superior parietal lobule (SPL1) (Figure 1c,d; 5, 45 and 46]). Each of these Edoxaban topographic areas contains a continuous representation of the contralateral visual field and is delineated from neighboring areas according to alternating representations of the upper and lower vertical meridian (Figure 1a,b). Topographic maps have also been identified in frontal cortex 47 and 48]. One such map is located in the superior branch of precentral cortex (PreCC), in the approximate location of the human frontal eye field (FEF), and a second one in the inferior branch of PreCC (Figure 1c,d). Utilizing such advanced mapping techniques, a recent functional magnetic resonance imaging (fMRI) study (see Figure 2a for an illustration of the task) found attention signals (see Figure 2b) in topographic frontal and parietal areas to be spatially specific: response magnitude was significantly greater when attention was directed to objects in the contralateral, relative to the ipsilateral, visual field [6••]. With the exception of an area in the left superior parietal lobule, known as SPL1, each topographic area in frontal and parietal cortex individually generated this contralateral spatial bias that was on average balanced between the two hemispheres (Figure 2c).