Methods
We developed a biologically inspired neural network model of the human primary visual system, consisting of two retinas, two layers of dorso-lateral geniculate nucleus and section B and C of layer 4 of the primary visual cortex. The model was built using GENESIS (www.genesis-sim.org) and comprises about 150,000 neurons. Three different kinds of neurons were incorporated, namely thalamic relay neurons, and excitatory and inhibitory cortical neurons. The processing of input in the retina was simply modeled as random-spike units, where the average firing rate corresponds to the input intensity. The neurons consisted of a soma, an axon and two or four dendrites for relay or inhibitory and excitatory neurons, respectively. We used different ionic channels to reproduce the desired firing behaviour. Synaptic transmission was implemented using the built-in excitatory and inhibitory synaptic channels.