Example Trials of the Integrate-and-Fire Attractor Network Simulations

(A) Trials in which no recall stimulus was applied to S1, and spontaneous firing continued until the end of the trial in the “spontaneous” simulation condition. However, on one of the trials illustrated, the firing increased as the network climbed into one of the attractors because of the statistical fluctuations caused by the spiking dynamics.

(B) Trials in which a recall stimulus was applied to S1 at 0–500 ms, and continuing firing normally occurred until the end of the trial in the “persistent” simulation condition. However, on one of the trials illustrated, the firing decreased as the network fell out of the attractor because of the statistical fluctuations caused by the spiking dynamics. In these simulations, the network parameter is w₊ = 2.1, and the modulation of the synapses is −NMDA and −GABA. This corresponds to a reduction of 4.5% and 9% in the currents produced through these synapses, respectively. The average firing rate of all the neurons in the S1 pool is shown.