Multiple bumps can enhance robustness to noise in continuous attractor networks
Fig 7
Bump trapping due to connectivity noise at low drive.
(A–C) Networks with 600 neurons, 1 bump, and the same realization of connectivity noise of magnitude 0.002. (A) Theoretical values for drift velocity as a function of bump position using Eq 24. (B) Bumps drift towards trapped positions over time. The drive is b = 0. Arrows indicate predictions from vconn(θ) crossing 0 with negative slope in A. Lines indicate simulations with different starting positions. (C) Bump trajectories with smallest positive and negative drive required to travel through the entire network. Respectively, b = 0.75 and b = −0.52. The larger of the two in magnitude is the escape drive b0 = 0.75. Note that positions with low bump speed exhibit large velocities in the opposite direction in A. (D and E) Networks with multiple realizations of connectivity noise of magnitude 0.002. (D) Escape drive decreases with bump number under linear mapping and remains largely constant under circular mapping. Networks with 600 neurons. (E) Escape drive increases with network size under linear mapping and remains largely constant under circular mapping. Networks with 3 bumps. Points indicate simulation means over 48 realizations and bars indicate standard deviations. Dotted gray lines indicate Eq 26 averaged over 96 realizations.