Fig. 4

Activation of pyramidal neurons reduced the RF area and background noise. The top of the graph shows PSTHs of a single unit obtained during the RF mapping procedure in the CaMKII virus-injected rat. The location of each PSTH represents the location of the visual stimulus on the monitor. For clarity, only a fraction of the PSTHs are shown as indicated by broken line rectangles on the response maps at the bottom of the figure. The gray bars below each PSTH indicate the time when the visual stimulus was presented. In the middle of the figure, the peak responses in the control and during 465 nm LED stimulation are shown. The 465 nm LED stimulation period (a train of 40 ms long pulses at 10 Hz) is indicated by a darker background on the right-hand side of the PSTH. Bottom: a grayscale-coded representation of the responses according to the visual stimulus location on the monitor. Broken line ellipsoids indicate 2D Gaussian fits of the responses. Note the much stronger background response in the control conditions.