Network mechanisms underlying the role of oscillations in cognitive tasks
Fig 6
Forced switching with oscillations from an E-I network.
A The network is built such that an excitatory population (E1) and an inhibitory population (I) form a circuit that can generate oscillatory output via the excitatory population (E1), which is fed into another excitatory populations (E2). The latter is in the bistable regime. B Bifurcation diagram of the E1-I-circuit in the parameters ηe and ηi. The organizing bifurcations are a pair of saddle-node bifurcations (SN) of the fixed points, and a Hopf branch (H) that connects to one of the saddle-node branches via a Bogdanov-Takens codimension-two point (BT). (Limit cycles are found below the Hopf branch). C Firing rates and raster plots of the population outputs as a result of the parameter tuning. Time traces of population E2 are portrayed for both stable initial conditions (node and focus). By choosing ηe and ηi accordingly, recall (ηe = −4.4, ηi = −18), clearance (ηe = −1, ηi = −5.5) and bistable response (ηe = 0, ηi = −2) can be observed. Other parameters: ,
, Δ = 2, τ = 20ms. Mean current of E2: η = −10.