Figure 1.
Top, Diagram of the two-pool network model used for the simulations. All connections from the excitatory neurons (the A, B, and nonspecific pools on the right) are AMPA- and NMDA-mediated. The fast and slow models have only one inhibitory pool, in which all the neurons have the same τGABA. The connections from inhibitory neurons shown on the left are GABA-mediated. The letters or numbers next to the arrows specify the synaptic weights. Middle, left, Firing rates for all the pools for sample trials of the original model. Thick gray line, specific pool A; thick black line, specific pool B; thin gray line, nonspecific pool; dotted black line, inhibitory fast pool; dotted gray line, inhibitory slow pool. Input cues are switched on at t = 4 s (arrows). The vertical dashed line marks the moment where the decision was taken, as measured by the criterion described in the text. Bottom, left, Rastergrams for the same two trials, showing the spiking activity for 10 randomly chosen neurons from each population. Middle and bottom, right, Same as with middle and bottom, left, but with the two-pool model.