Figure 4

Thresholding floor-effect. The dentate gyrus (A) was thresholded and the selected pixels are displayed in black (B). There are pixels that are a part of the DG (indicated in red) that should be included in the calculation of the mean GL, but have fallen below the threshold level and are therefore excluded. This biases the GL value upward, and creates a floor-effect, where no pixels below the threshold are included in the calculation of the mean GL.