Correlation-based model of artificially induced plasticity in motor cortex by a bidirectional brain-computer interface
Fig 7
(A) STDP function W(Δt, Jij). Dashed black line indicates the W+ and W− functions. Coloured lines indicate the full, weight-dependent rule W for different synaptic weight values Jij shown in the color bar. (B) Top: Periodic external rates delivered to each neural group (as in Fig 1). Middle: sample spike raster plot from a simulation subject to rates plotted above with sparse, homogeneous connectivity J(0) (N = 60). (C) Simulated synaptic evolution J(t) with Jmin = 0, Jmax = 0.1 and η = 10−8 under baseline conditions (stimulation “off”) as in B. Left: initial connectivity matrix with connectivity probability p = 0.3 and Jij(0) = Jmax/4 (grayscale: white = Jmin, black = Jmax). Middle: 10 evolving weights J(t) randomly selected from each of 9 possible pre- and post-synaptic group combinations. Color indicates whether a synapse connects neurons within the same group (orange) or across different groups (purple). Right: synaptic matrix J(t) at the end of the simulation, once group-averaged weights have reached steady state.