Figure 5. Similar dynamics in competitive network simulations and neural data.

A) Schematic of the competitive ensemble model used for simulations. B) Phase plane plot of the recurrent input to each ensemble. The ‘pre-target’ state as indicated by the arrow is maintained by providing a small bias current to ensemble 2. Light grey lines show individual trial simulations, with the gray circles indicating the state of the network at the offset of the transient stimulus. The dashed line reflects the boundary between two attractors (see Figure S5 for more details). In ‘miss’ trials the network returns to the pre-target node, whereas in ‘hit’ trials the network diverges to a different stable node (at the bottom right of this plot). C, D) Activity profile for two example simulations of a near-threshold stimulus; external inputs I₁ and I₂ are shown below traces. C) Recurrent activity (S, which is proportional to firing rate) of ensemble 1 in which the transient stimulus did (red) or did not (black) lead to a stable transition. D) Same as (C), except for ensemble 2, with the successful transition shown in blue. E, F) Activity profile for hit and miss trials of enhanced (E, average of n=3 units) and suppressed (F, average of n=18 units) neurons. Note that sustained transitions in ensemble 1 and hit trials in the enhanced population are both associated with a curved activity trajectory, indicated by the green asterisks (in B, C and E).