The Generation and Modulation of Distinct Gamma Oscillations with Local, Horizontal, and Feedback Connections in the Primary Visual Cortex: A Model Study on Large-Scale Networks

Figure 7

Size dependence of gamma in the HC network with and without FB. The calculation of two indexes (suppression index (SI) and frequency change (FC)) that capture the size-dependent property of gamma was shown in (a) (suppression index) and (b) (frequency change). The curves in different colors mean the power spectrums under different stimulus sizes. (c) shows an HC network without FB driven by a small stimulus (left panel) and by a large stimulus (right panel). Components weakly or not activated by the stimulus are shown as light red or light blue color and components in red or blue are those strongly activated by the stimulus. The left column of (d) shows how the suppression index changes with strengths of and for slow (upper panel) and fast gamma (lower panel) oscillation, and the right column of (d) shows how gamma frequency changes with strengths of and for slow (upper) and fast gamma (lower) oscillation. (e) shows a network with both HC and FB driven by a small stimulus (left panel) and by a large stimulus (right panel). Notice that the network in (e) and (c) are the same, except that network in (e) has FB, but the network in (c) does not. The panels in (f) are also similar to those in (d), but the -axis and -axis is for strengths of and instead.

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