VIRTUAL RETINA allows large-scale simulations of biologically-plausible retinas, with customizable parameters, and different possible biological features:
- Spatio-temporal linear filter implementing the basic Center/Surround organization of retinal filtering.
- Non-linear contrast gain control mechanism providing instantaneous adaptation to the local level of contrast. This stage is modelled through dynamical adaptation conductances in the membranes of bipolar cells; the resulting model reproduces contrast-dependent amplitude and phase non-linearities, as measured in real mammalian retinas by Shapley & Victor 78.
- Spike generation by one or several layers of ganglion cells paving the visual field. Magnocellular and Parvocellular pathways can be modelled in the same framework according to the parameters chosen. Large-scale simulations can be pursued on up to 100,000 spiking cells.
- Possibility of a global radial inhomogeneity modeling the foveated organization of mammalian retinas. In this case, the spatial scales of filtering, and the density of spiking cells, both depend on the eccentricity from the center of the retina.
- Possibility to include a basic microsaccades generator at the input of the retina, to account for fixational eye movements.

VIRTUAL RETINA is now part of the ENAS software so that you can use it easily thank to our friendly Graphical User Interface!

VIRTUAL RETINA is under INRIA CeCill C open-source licence (IDDN number IDDN.FR.001.210034.000.S.P.2007.000.31235), so that you can download it, install it and run it on your own sequences.

Project leaders: Pierre Kornprobst and Adrien Wohrer

Contributors: Bruno Cessac, Maria-Jose Escobar, Sélim Kraria, Daniela Pamplona, Thierry Viéville.

General description of VIRTUAL RETINA

• Virtual Retina: A biological retina model and simulator, with contrast gain control, A. Wohrer and P. Kornprobst, Journal of Computational Neuroscience, 26(2):219, 2009
• Tutorial explaining both installation procedure and usage of the software in detail. Some README files in the archive also contain some information.
• Typically, the program is called under a LINUX shell, with a syntax that looks like this:
  Retina path/to/my/test_sequence*.pgm -ret my_retina.xml -r 10 -outD path/to/my/saving/directory
  with possible options:
  • test sequences can be 2d frames under any usual format (as here), or directly a .inr 3-dimensional file.
  • -ret gives the path to the retina definition file in xml format.
  • -r 10 : each input frame is presented to the retina for a duration of 10*(retinal time step) = 50 ms in this case.
  • -outD : path to the directory where all simulation files will be saved.
  • etc.
  Full list of options by typing -h.

Papers using VIRTUAL RETINA

• Microsaccades enable efficient synchrony-based coding in the retina: a simulation study, T. Masquelier, G. Portelli, and P. Kornprobst. Scientific Reports, 6:24086, April 2016.
• Modelling of a retinal ganglion cell with simple spiking models, P. Vance, S. A. Coleman, D. Kerr, G.P. Das, and T.M. McGinnity, In IEEE Int. Jt. Conf. Neural Networks, pages 1–8, 2015.
• Evaluating SPAN Incremental Learning for Handwritten Digit Recognition, A. Mohemmed, G. Lu, and N. Kasabov, In Neural Information Processing, pages 670–677. Springer Berlin Heidelberg, Berlin, Heidelberg, 2012.
• Relative spike time coding and STDP-based orientation selectivity in the early visual system in natural continuous and saccadic vision: a computational model, T. Masquelier, Journal of Computational Neuroscience, 32(3):425–441, 2012.
• Another look at the retina as an image scalar quantizer, K. Masmoudi, M. Antonini, and P. Kornprobst, In Proceedings of the International Symposium on Circuits and Systems (ISCAS), 2010.

This work was supported by the EC IP project FP6-015879 FACETS