Network states as a function of global inhibition amplitude in the lower and higher area.

<p><b>A.</b> The colour map shows the network state dependence on parameter values (other parameters set to default values except as stated, 5 repeats of 2 seconds of simulated activity for each condition), with green reflecting poor spike separation, red selective representation of a single item (F-multiplexing), and blue alternation between different items (LJ-multiplexing); see Methods for details of the indices used to measure spike separation and item representation. <b>B–E.</b> Polar plots of higher level activity, spike probability (across simulation repeats) as a function of slow oscillation phase. Colours (red, blue and green) indicate spikes driven by the high, mid and low contrast objects respectively. The different plots correspond to the different network states, as marked in panel A. <b>B.</b> Without global inhibition in either area, all items were represented but there was poor spike separation (green area in A). <b>C.</b> With global feedback inhibition only in the higher area, the network displayed F-multiplexing, with a single item repeatedly represented at gamma frequency within each slow cycle (red area in A). <b>D.</b> The inclusion of global feedback inhibition in the lower area instead yielded LJ-multiplexing, with alternation between different items (blue area in A). <b>E</b>. With global inhibition in both areas, the network tended to generate fewer spikes, skipping some of the available gamma cycles. Multiplexing tended to be LJ-style.