FIGURE 5.

Neuronal responses to periodic glutamatergic and GABAergic inputs of γ-frequencies in the case when the input time-width is (ms). (a) The top panel shows the numerically calculated bifurcation sets with respect to Δt and under the fixed parameters T = 25 (ms), (ms), and that gives a 1:2 phase-locked response, i.e., 20 Hz firing in the absence of GABAergic inputs. Solid and dashed lines indicate numerically calculated saddle-node and period-doubling bifurcation curves, respectively. The bottom panel is a corresponding result by explicit simulation of Eqs. 1 and 2 using the Runge-Kutta method. (b) The relationship between the time difference Δt (ms) and the neuronal firing rate for a fixed value of the maximum conductance of the GABAergic inputs (nS).