The sizes of individual domains (12 ± 7 μm, mean ± s.d. FWHM, n=107 domains) were considerably larger than the spacing between excitatory synapses on interneuron dendrites (<1 μm)45 (Supplementary Fig. 13b, c). Nearby domains with distinct preferred orientations often overlapped (Supplementary Fig. 13b). The large size of these domains might reflect spatially clustered input with shared orientation preference. Alternatively, individual domains might be dominated by a few sparse, randomly distributed strong inputs46, amplified by local postsynaptic mechanisms47
