The surface-rendered brains show fMRI BOLD activations and deactivations relative to when subjects are fixating in an otherwise blank field (i.e., the baseline, left panel), when searching through letter distracters of an RSVP display (middle panel, ventral network is deactivated, dorsal network is activated), and when detecting a digit target in the display (right panel, both networks are activated along with other regions) (Shulman et al., 2003). The bottom panel shows spiking activity in monkey locus coeruleus neurons during analogous periods: an inattentive period in which a task is poorly performed and tonic activity is high, an attentive period in which the task is performed well and tonic activity is decreased, and target detection, which produces a phasic increase in activity (Usher et al., 1999). The inset trace shows event-related potentials recorded from the scalp of a human when a target is detected in a completely separate experiment, with the large positive deflection indicating the P300.