Applying Super-Resolution and Tomography Concepts to Identify Receptive Field Subunits in the Retina
Fig 5
Robustness of STR to model variations.
Each row demonstrates the effect on STR of one variation of the model via a sample simulation. Layout of the rows is the same as in Fig 2. Top row shows a model with increased subunit overlap (see Methods for details), apparent from the 1.5 σ subunit ellipses. In the second row, the Gaussian-shaped subunits were replaced by subunits with a cosine profile. For comparability, the ellipses in the subunit layout depiction are 1.5 σ ellipses of Gaussians fitted to the cosine subunits. Third row contains a replacement of the rectified-linear nonlinearity with a rectified-quadratic nonlinearity. Weights of the subunits in the fourth row were not all equal as in the default model, but chosen according to a large spatial Gaussian. In this example, the strongest subunit weight was roughly eight times that of the weakest weight. In the bottom row, a base activity of three expected spikes was added to all responses.