Most importantly, in contrast to the findings in the VWFA, there is a significant linear interaction between the response to motion-dot words and the other stimulus types (t = 3.08, p < 0.001), indicative that the increasing response to higher visibility is only present for the motion-dot Selleckchem Lonafarnib words. Visibility of the motion-dot stimuli is tied to motion coherence. Depending on stimulus parameters, hMT+ responses may increase simply due to motion coherence (Braddick et al.,

2001). To test whether the increase in hMT+ responses with word visibility is caused by the increase in coherence alone, we separately measured responses to coherent and incoherent moving dots that did not define a word shape. The dots’ motion direction was coherent or incoherent, and their other motion parameters were matched to those of the motion-dot words. There is no significant hMT+ response difference between responses to coherent and incoherent motion-dots

(Figure S1B; paired t test, t[3] = 0.59, p = 0.60). However, as in the event-related paradigm in the main experiment, there is a significant hMT+ response difference between motion-dot words and incoherent motion (paired t test, t[3] = 5.47, p < 0.05). Performance on the lexical decision task is strongly correlated (Pearson r = 0.77, p < 10−4) with hMT+ BOLD response modulation for motion-dot stimuli (Figure 4B), again suggesting the importance of hMT+ activity in correctly parsing feature patterns when stimuli are defined by motion. There is also a correlation (r = 0.54, p < this website Adenosine 0.01), although weaker, between lexical decision performance and hMT+ BOLD responses to luminance-dot stimuli. There is no significant correlation (p = 0.35) between hMT+ responses and performance on words defined by line contours. We used transcranial magnetic stimulation (TMS) to test the necessity of area hMT+ for processing word stimuli. Specifically, we identified the location of hMT+ in each individual and then used TMS to disrupt neural activity in that region while the subject performed the lexical decision task (see Experimental Procedures for

details). Subjects’ baseline performance was matched across stimulus types at 82% correct performance for each feature type (top dashed line in each plot in Figure 5). Applying TMS to left hMT+ disrupts baseline performance only for stimuli defined by motion features (Figure 5), but not for stimuli defined by other visual features. We used a linear mixed effects model, with subject intercept considered a random factor, to estimate the effect of TMS at different stimulus-pulse onset asynchronies (SOAs) on performance. A significant decrease in performance occurs only at an SOA of 87–132 ms (t[42] = −5.14, p < 0.001). These latency values are consistent with timing between stimulus onset and neural responses in area MT of the human (Prieto et al., 2007) and nonhuman primate (Raiguel et al., 1999).