Tuning width distributions. Tuning width distributions. The responses of each cell were fit with a Seung–Sompolinsky curve equation (see Materials and Methods). As the narrowness of the tuning of the cell increases, the tuning width parameter decreases. Glob cells (A-C) had lower tuning width values on average than interglob cells (D-F) for all luminance levels. Top row, Histogram for high-luminance stimuli; middle row, equiluminant stimuli; bottom row, low-luminance stimuli. Dotted line marks the median tuning width. Shading indicates the goodness of fit of the sine exponent curve: white, all cells; light gray, cells with curve fits of R2 > 0.4; dark gray, R2 > 0.6; black, R2 > 0.8. Kaitlin S. Bohon et al. eneuro 2016;3:ENEURO.0039-16.2016 ©2016 by Society for Neuroscience