“…The reason for this is that a salient event can induce multiple, simultaneously active, regionally overlapping, and functionally separable responses which add to existing neuronal background activity, in other words, event-related processes are spatially and temporally mixed across the brain. The scalp EEG samples a volume-conducted, spatially degraded version of the responses, where the potential at any location and latency can be considered a mixture of multiple independent timecourses that stem from large-scale synchronous field potentials (Makeig, et al, 2004a;Onton, et al, 2006). Similarly, the neurovascular transformation of the distributed neuronal activity into hemodynamic signals (Lauritzen, et al, 2003;Logothetis, 2003) affords detection of blood oxygenation level dependent responses (BOLD, Ogawa, et al, 1990) that are temporally degraded and spatially mixed across the fMRI volume (Calhoun, et al, 2006a;McKeown, et al, 2003).…”