Fig. S4

(related to Figure 4). Composite maps reveal a laminar and retinotopic organization of direction- and orientation-selective responses using DSI and OSI metrics. (A and B) Combined composite parametric maps that represent the spatial organization of responses across all subjects colour-coded for individual sub-populations of directionselective (direction-selective index – A) and orientation-selective (orientation-selective index - B) responses overlaid on an anatomical image (grey scale). Voxels that lie within ±20º of 9 the peak of each fitted von-Mises distribution (inset histograms) are colour-coded and mapped on the individual (inset) and combined composite maps. Within the individual parametric maps voxel brightness is proportional to the summed incidence of each functional response across all fish imaged. (C and D) The composite maps of direction-selective and orientation-selective responses respectively are rotated to enable line plots representing the summed incidence across each axis: between the yellow lines represents an approximately linear segment of the neuropil to assess lamination and; between orange lines represents visual field to assess retinotopic organization. (E) Relative histograms (normalising area under each curve) of direction-selective responses (dashed line) and orientation-selective responses across laminar of the tectal neuropil (derived from lower line-plots in C and D). Note the area of intersection between all direction-selective (solid lines) and orientationselective voxels (dashed lines) was only 16% of the total area - confirming the laminar segregation of direction- and orientation-selective responses. Orientation of each image is indicated bottom left (P=posterior, L=lateral). Scale bar=20μm in C and D.