Figure 1

The top panel shows the T₁ intervals (with T₂ = 60 milliseconds) for the existence of different families of entrained periodic oscillations (green for sub-threshold oscillations, red for 1-spike oscillations, dark blue for 2-spike oscillations, and light blue for 2-spike oscillations with a delayed second spike.) Panels A, B, C, and D illustrate the periodic excitatory signals with T₂ = 60 milliseconds and T₁ = 1.014, 5.399, 8.545, and 16.15 milliseconds, respectively. Panels A1, A2, B1, B2, C1, C2, and D1 show the time series plots of the different types of periodic oscillations entrained to the excitatory signals with T₁ values indicated in the top panel.