Noise can turn activity-silent and persistent firing regimes into transient WM activity.

A Bifurcation diagram for a STP rate network without LPA signaling. The grey-shaded area denotes the regime in which a stable limit cycle exists. Presenting a sufficiently strong WM cue to silent networks in the bistable regime evokes persistent WM activity. B-C Population activity for two rate network simulations in the silent and the persistent regime, with and without noise (of amplitude σy) added to the synaptic variable y. The grey shaded area denotes the cue stimulus. In the silent regime (E 56] (‘stabilizing noise’). In the regime of persistent limit cycles, noise can disrupt oscillations (‘destabilizing noise’). D-E Typical trajectories of transient limit cycles emerging from stabilizing (orange line, D) and destabilizing noise effects (magenta line,E) at baseline input levels Ibase = -3.3 (left) and Ibase = -2.9 (right). Black lines show a representative example of a noise-free trajectory (left) and the limit cycle (right). Remaining rate network parameters: see Table D in S1 Text.