Fig. 4: Network dynamics modeling of multiple heterotopic downstream regions.
A Diagram of the network model with self-projections and heterotopic projections. B Definition of heterogeneity parameter h. Within an example model encompassing four regions (N = 4), each region contains three heterotopic downstream targets. Neuron subsets, each comprising six neurons (N = 6), project to respective downstream regions. The total number of projecting neurons in an upstream region ranges from its minimum value (mmin = n) when neuron subsets completely overlap, to its maximum value (mmax = n(N-1)) when there is no overlap between subsets. Parameter h, normalized from m, scales from 0 (complete overlap) to 1 (no overlap). The diagram on the right illustrates how h and m regulate the overlap between neuron subsets, where each small circle represents a projecting neuron, and large gray contours delineate different neuron subsets. C Adjusting h changes the heterogeneity level. In simulations with N = 30 regions, the distribution function representing heterogeneity is shown for different h values (0.01, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8). An increase in h shifts the distribution P(N = i) leftward, indicating a rise in heterogeneity. D The graphs show single neuron activities (gray lines) and the mean neural activity (red lines) under a noise level of 0.05, revealing how heterogeneity influences network dynamics. In a completely non-heterogeneous scenario (h = 0), the network alternates between asynchronous and synchronous states. At h = 0.5, state alternation frequency decreases, and at h = 1, the network maintains at one state. E The duration of state transitions decreases as heterogeneity increases. Durations are normalized relative to the maximum transition duration observed at different noise levels (0.01, 0.02, 0.05, 0.1, 0.2). F, G Both the normalized strength and variability of inter-regional correlations during asynchronous phases exhibit a decline as heterogeneity increases. Source data of (C, E–G) are provided as a Source Data file.
