Figure 4. Mechanism for Formation and propagation of sequence.

The currents from the matrix J_{PINned, 8%} (red trace in the top left panel) and from its components are examined here. Band-averages of J_{PINned, 8%} cause the bump to form, as shown in the plot of the current from mean J_{PINned, 8%} to one neuron in the network (red trace in the top panel on the right, see also Figure 3C). The cooperation of the fluctuations (whose currents are plotted in red in the middle panel on the left) with the external inputs (in yellow in the bottom left) causes the bump to move. We demonstrate this by considering the currents from the fluctuations around mean J_{PINned, 8%} for all the neurons in the network combined with the currents from the external inputs. The summed currents are realigned to the t_COM of the bump and then averaged over neurons. The resulting curve, an aligned population average of the sum of the fluctuations and external inputs to the network, is plotted in the bottom panel on the right, and reveals the asymmetry responsible for the movement of the bump across the network.