Weak LPA signaling implements slow modulation of the mean transient WM duration via its influence on presynaptic calcium binding.

A-C Analysis of the STP+LPA rate model (see Models and methods and Table C in S1 Text). Parameters: ΔU = 0.1, M = 0.2(τL/10sec), Ub = 0.16, σ = 0.1, remaining parameters: Table D in S1 Text. A WM durations for 15 simulations at each of eight values of τL. Durations of transient activity slowly increase with τL. Inset: Distribution of transient WM durations of 100 simulations at τL = 10sec. B-C Two simulations at τL = 10sec. Panels as in Fig 4. D-F Analysis of a STP+LPA spiking network model (see Models and methods, Table A in S1 Text). Parameters: ΔU = 0.1, M = 0.6, Ub = 0.2, remaining parameters: Table B in S1 Text. D Transient WM durations for 100 simulations for each of 46 values of τL. The time constant of presynaptic LPA unbinding τL regulates the duration of transient active WM representations across a broad range of biologically realistic values. E-F Two simulations for τL = 38sec with different transient durations. Panels as in B and C but the subplot in the center shows a rasterplot of 50 neurons of the selective population instead.