In particular, we examined activity in the rTPJ, which previous studies identified as a key region for stimulus-driven this website orienting of spatial attention (Corbetta et al., 2008). This targeted ROI analysis revealed that rTPJ activated more for attention grabbing than non-grabbing characters

(T = 2.02; p < 0.028; see signal plot in Figure 3A). We further confirmed the link between rTPJ activation and spatial attention by covarying BOLD activation for the attention grabbing characters with the corresponding attention-related parameters (processing time and amplitude of visuo-spatial orienting; see Figure 2D). This revealed a significant modulation of the transient rTPJ response by the timing parameter (A_time: T = 2.42; p < 0.017; see Figure 3B, left). Specifically, we found that characters requiring longer processing times activated rTPJ more than characters that required less time. At the whole-brain level, the peak of modulation was located in the right pMTG (see right panel in Figure 3B and Table 2). The amplitude parameter was also found to modulate

activity in rTPJ (A_ampl: T = 2.22; p < 0.024). At the whole-brain level, Trichostatin A nmr modulation by amplitude was found in the right MFG that also exhibited an overall response to the characters’ onset (see Figure 3A); also, the IFG, medial superior frontal gyrus, and supramarginal and angular gyri did not respond to the characters’ onset (see Table 2). All regions modulated by A_ampl showed greater activation for characters that were presented close to the currently attended location (i.e., larger BOLD responses for L-NAME HCl smaller amplitudes). Additional analyses using gaze position data acquired in the scanner (in-scanner indexes of orienting efficacy) confirmed the modulation

of activity in the rTPJ for attention grabbing versus non-gabbing characters (while the effect of A_time and A_ampl did not reach full significance) and revealed related effects in the right IFG (rIFG) using a more targeted ROI approach; see Supplemental Experimental Procedures. The in-scanner indexes were used also to analyze the imaging data acquired during the corresponding free-viewing fMRI runs (cf. Table S1 in Supplemental Experimental Procedures). We tested all attention-related effects in the overt viewing conditions, and directly compared overt and covert conditions when an effect was present in one condition, but not in the other. For the No_Entity video, we found activations related to mean saliency (S_mean) in occipital cortex bilaterally as well as in the left aIPS (see Table 1, rightmost column), as in the covert viewing condition.