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 2

Gamma oscillations generated in networks with different connectivity patterns. Panels (a–d) show networks with different connection patterns. The difference among (a–d) is that (a) shows a network with feedforward (FF) and local connections (local RC); (b) shows a network with local RC and long-range horizontal connection (HC) but without any feedback connection (FB); (c) shows a network with local RC and FB but without HC; and (d) shows a network with local RC, HC, and FB. The local field potentials (LFP) from networks with the four different connection patterns are shown in panels (e–h) correspondingly. The power spectrums of the LFPs were estimated and shown in (i–l) ((i) for the LFP in (e); (j) for that in (f); and (k) for that in (g); and (l) for that in (h)). The black curve shows the power spectrum during the visual stimuli, while the black dashed line shows the power spectrum when networks were driven by a visual stimulus with zero contrast. There is only one gamma in (i) and (k), but two gamma oscillations (slow and fast gamma as noted) appeared in (j) and (l).