Figure 4.

LFP tuning in the direction and contrast configuration. A, Color plot showing the relative LFP-power across frequency (2 Hz bandwidth) and test-pattern motion directions during fixation trials averaged across recording sites (n = 81). The color represents the change in power during stimulus presentation relative to the baseline activity (log-ratio). For visual display purposes, the data points across frequency and stimulus pairs were interpolated. The graph on the right shows the mean slope (95% confidence interval shown in gray) of a regression line fitted to the data in predetermined frequency bands (see B and C, and Results). The slope was computed for each recording site and then averaged across sites. B, C, Mean relative LFP-power in different frequency bands below (B) and above (C) 30 Hz, for the population of recording sites (n = 81) as a function of the test-pattern motion direction. Error bars, SEM. Note the different scale between the panels. D–F, Data in the contrast configuration. Same conventions as above.