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R. P. Ignatius
Fig. 5 Variations of average firing rate (Hz) of the network with α and G syn at D = 0.5. With
the increase in α, the network displayed a wide range of frequencies from delta to beta waves
(non-chaotic neurons)
is decreased. As D and G syn are varied, the complete synchronized regions found to
be lost.
3.3 Average Firing Rate (F)
From Fig. 5, it is clear that the network displayed a wide range of frequencies as α is
increased. For very low values of α (<0.1) network showed Delta waves (0.5–3 Hz).
When α is gradually increased (but <0.8), the network activity is also changed to
Theta (3–8 Hz), to Alpha (8–12 Hz) and finally to Hi-Beta range. When α is increased
above 0.8, firing rate gradually decreased to low-Beta frequency. But high values of
α causes an increase in average firing rate of the network, due to increased coupling
strength. Since network displayed mainly two states of synchronization with increase
in α value, a representative value for α is chosen from both of these regions and the
response of the network towards variations in D and G syn is investigated. From
Fig. 6a, it is clear that Beta waves (waves of 12–40 Hz) dominate in the network.
Average firing rate of the network is invariant with increase in G syn . Whereas with
increase in D, average firing rate gradually shifted from Hi-Beta to Lo-Beta, i.e.
24–12 Hz. For small values of D all the neurons in the network spikes irregularly
(Fig. 7). They also displayed near-death spikes.
The behaviour for α = 0.8 is very much different, because of the rich dynamics
of noise at these values (Fig. 6b). The average firing rate exhibits an increase with
respect to D and G syn . The network displayed Gamma frequency (38–42 Hz) at these
parameter regions.
R. P. Ignatius
Fig. 5 Variations of average firing rate (Hz) of the network with α and G syn at D = 0.5. With
the increase in α, the network displayed a wide range of frequencies from delta to beta waves
(non-chaotic neurons)
is decreased. As D and G syn are varied, the complete synchronized regions found to
be lost.
3.3 Average Firing Rate (F)
From Fig. 5, it is clear that the network displayed a wide range of frequencies as α is
increased. For very low values of α (<0.1) network showed Delta waves (0.5–3 Hz).
When α is gradually increased (but <0.8), the network activity is also changed to
Theta (3–8 Hz), to Alpha (8–12 Hz) and finally to Hi-Beta range. When α is increased
above 0.8, firing rate gradually decreased to low-Beta frequency. But high values of
α causes an increase in average firing rate of the network, due to increased coupling
strength. Since network displayed mainly two states of synchronization with increase
in α value, a representative value for α is chosen from both of these regions and the
response of the network towards variations in D and G syn is investigated. From
Fig. 6a, it is clear that Beta waves (waves of 12–40 Hz) dominate in the network.
Average firing rate of the network is invariant with increase in G syn . Whereas with
increase in D, average firing rate gradually shifted from Hi-Beta to Lo-Beta, i.e.
24–12 Hz. For small values of D all the neurons in the network spikes irregularly
(Fig. 7). They also displayed near-death spikes.
The behaviour for α = 0.8 is very much different, because of the rich dynamics
of noise at these values (Fig. 6b). The average firing rate exhibits an increase with
respect to D and G syn . The network displayed Gamma frequency (38–42 Hz) at these
parameter regions.