(2010) found symmetrical interactions between temporal and spatial judgments in monkeys, so see more clearly more work is needed on this

issue. Symmetrical or not, the spatial and temporal domains clearly interact in perceptual decisions in both humans and monkeys. Although both imaging and psychophysical studies have suggested a domain-general representation of magnitude, a different organizational principle has emerged from the present findings. We found domain-specific perceptual processing at the single-cell level, with the intermixing of these neurons leading to domain generality at the regional level (Genovesio et al., 2011). The finding of cell-level domain specificity in the caudal and dorsolateral PF cortex does not rule out the possibility of domain-general mechanisms elsewhere in the brain or in tasks that require magnitude judgments across domains. However, in the parts of PF sampled and in the present tasks, we found no coding of abstract magnitude in individual neurons. The finding of domain specificity at the single-cell level is consistent with the imaging findings, which describe activations

in voxels comprising thousands of synapses and neurons. VX770 Nearby domain-specific cells would probably create a domain-general signal at the voxel level, and domain-general coding of goals could also contribute to the imaging results. So our findings do not conflict with imaging results, but they seem to clash with the psychophysical findings showing perceptual interactions between the spatial and temporal domains. Perhaps the cells that encode nonspatial goals can help resolve this apparent discrepancy. These domain-general neurons

are intermixed with cells that encode relative magnitude in each domain: spatial and temporal. Goal representations have been reported previously in the PF cortex, where they have been linked to the concept of prospective coding (Kusunoki et al., 2009, Rainer et al., 1999 and Saito et al., 2005). The terminology of Schall (2001) might prove helpful here. He distinguished between decisions, which involve the analysis of sensory inputs for Ketanserin perception, and choices among goals or actions. Our findings suggest that the psychophysical interaction across cognitive domains occurs at the level of goal choices, not at the level of perceptual decisions. The cell population that encodes response goals could serve as a shared resource that generates interference. Domain specificity at the level of perceptual decisions and domain generality at the level of goal choices could account for the neuronal, imaging, and behavioral data. Our results also bear on theories of the PF cortex that appeal to a global workspace, domain generality, or multiple cognitive demands (Baars et al., 2003, Duncan, 2010 and Wilson et al., 2010).