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. Author manuscript; available in PMC: 2013 Aug 14.
Published in final edited form as: Neuron. 2012 Jan 12;73(1):159–170. doi: 10.1016/j.neuron.2011.12.013

Figure 3. Slight Modulation of Pyr Cell Tuning Properties by PV Cells.

Figure 3

(A) Left: PSTH of Pyr cell response to drifting gratings during control (black) or Arch-mediated suppression of PV cells (green). Horizontal bars: black, stimulus presentation; blue, LED illumination. Right: the tuning of the cell is illustrated on polar (top) and Cartesian (middle) axes (black: control; green: PV cell suppression). The tuning curves plotted on Cartesian axes are fitted with a double Gaussian. Note the slight reduction in both orientation and direction selectivity indexes. Bottom: the Gaussian fits under control (black) and PV cell suppression (green) are normalized to the peak and superimposed for comparison. Error bars are the SEM. Note that the tuning sharpness during PV cell suppression remains essentially unaffected.

(B) Left: PSTH of Pyr cell response to drifting gratings during control (black) or ChR2-mediated activation of PV cells (red). Horizontal bars: black, stimulus presentation; blue, LED illumination. Right: the tuning of the cell is illustrated on polar (top) and Cartesian (middle) axes (black: control; red: PV cell activation). The tuning curves plotted on Cartesian axes are fitted with a double Gaussian. Note the increase in both orientation and direction selectivity indexes. Bottom: the Gaussian fits under control (black) and PV cell activation (red) are normalized to the peak and superimposed for comparison. Error bars are the SEM. Note that the tuning sharpness during PV cell activation remains essentially unaffected.

(C) Linear regression (line) of percentage change in Pyr cells firing rate at their preferred orientation versus the change in their tuning properties during PV cell photo suppression (green dots; n = 31) or PV cell photo activation (red dots; n = 14). p values (black) indicate the significance of correlation between in change firing rate and tuning property. Left: distributions of respective tuning properties (negative values indicate decrease in tuning property; p value indicates confidence that there is a significant difference; green: Arch versus control; red: ChR2 versus control). Bottom: distribution of change in firing rate. Arrows point to population medians.