Signal intensity of EPI.

<p>(A) Signal intensity maps showing EPI image quality in the calcarine sulcus. The color gradient indicates the mean signal intensity of the smoothed EPI time course data overlaid on the inflated cortex of the Talairach brain. The threshold of the color map was established at a TSNR of 40, and all the blue areas indicate a TSNR of at least 200. Simulations indicate that a TSNR of 40 (indicated in the map by light green) is the minimum necessary to reliably detect the effects between the conditions in the fMRI data <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0072728#pone.0072728-Murphy1" target="_blank">[40]</a>. (B) The signal intensities in the ROIs of V1. At the contralateral horizontal positions, the signal intensities in the 4 ROIs (0°, 16°, 32°, and 48°) were not significantly different (p = 0.06). At the upper and lower vertical positions, the signal intensities in the 3 ROIs (16°, 32°, and 48°) were not significantly different (p ≥ 0.35), but they were significant smaller than the signal intensities at the contralateral horizontal positions (p<0.05). The abbreviations are the same as those used in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0072728#pone-0072728-g003" target="_blank">Figure 3</a>.