Unsupervised learning for robust working memory
Fig 8
The effect of homeostatic plasticity under global perturbation.
A: Recovery of location-coded memory under homeostatic plasticity with target rate r0 = 20, learning rate αh = 10−8 and perturbation strength p = 30% in the E-to-E connections (arrow in D-F). B: Activity pattern at the end of the delay period after the recovery (arrow in C). C: Decrease of decoding error (black) and preservation of translation-invariance (red) with learning. D-F: Dependence of postsynaptic E-I ratio on target firing perturbation strength p (D), rate r0 (E), and learning rate αh (F). Note that, unlike Fig 6D, the E-I ratio is not defined by eigenvalue or in the Fourier domain. As homeostatic plasticity modifies all incoming synapses of a neuron with a common factor, we quantified the E-I ratio compared to that before perturbation for each neuron. The mean is shown in black, and the standard deviation across neurons is shown in grey shaded area. G-I: Decoding error and normalized deviation of spatial selectivity for various p (G), r0, (H), αh (I).