Multiple bumps can enhance robustness to noise in continuous attractor networks
Fig 3
Dynamics in a ring attractor network.
(A–C) Networks with 200 neurons and 3 bumps. (A) Synaptic inputs for populations L and R under drive b = 2. Snapshots taken at 150 ms intervals demonstrate rightward motion. (B) Bump velocity is proportional to drive. The connectivity shift is ξ = 2. (C) Bump velocity is largely proportional to connectivity shift. The drive is b = 0.5. (D–H) Networks with synaptic input noise. (D) Bump displacements for 48 replicate simulations demonstrating diffusion with respect to coherent motion. Networks with 200 neurons and 1 bump. (E and F) Mean bump velocity is proportional to drive and remains largely independent of network size, bump number, and noise magnitude. (G and H) Bump diffusion coefficient scales quadratically with noise magnitude, remains largely independent of drive, and varies with network size and bump number. The noise magnitude is σ = 0.5 in D, E, and G, and the drive is b = 0.5 in D, F, and H. Values for both bumps in two-bump networks lie over each other. Points indicate data from 48 replicate simulations and bars indicate bootstrapped standard deviations. Dotted gray lines indicate Eqs 8 and 10.