Article Figures & Data
Figures
- Figure 1.
Random-dot stimuli and a schematic illustration of disparity tuning curves of cells with activity that correlates with depth perception. A, The left and center dot patterns correspond to the left and right eye images, respectively, of a cRDS. In this example, the center region of the cRDS patch has a crossed disparity. The center and right dot patterns are mutually anticorrelated in the center region, composing the left and right eye images, respectively, for an aRDS. The center region has the same binocular disparity for both cRDS and aRDS. B, Hypothetical response tuning curves of a cell selective to horizontal disparity. The thin solid curve represents the tuning profile to cRDS. The dashed curve is the tuning profile to aRDS in the case in which the neuronal response can be described by the disparity energy model, as is typically seen in V1. The thick solid curve is the tuning profile to aRDS when the neuronal response correlates closely with depth perception. The peaks and troughs should approach the overall response average and exhibit little or no disparity sensitivity.
- Figure 2.
Responses of a V4 cell that lost sensitivity to horizontal disparities of anticorrelated stimuli. A, The raster plots and the corresponding PSTHs for the preferred disparity of the cell to cRDS of -0.2° (left column) and nonpreferred disparity of +0.2° (right column). The top row represents responses to cRDS, whereas the bottom represents responses to aRDS. B, The horizontal disparity tuning curve to cRDS (solid circles) and aRDS (open boxes). Error bars show the mean ± SEM of 10 trials. The Gabor functions fitted to the raw data points are superimposed (solid and dashed curves, respectively). The amplitude ratio for this cell was 0.06. The bottom dotted line represents the ongoing activity level, whereas the mean responses to left- and right-eye monocular presentations are shown on the right-hand side, marked as L and R, respectively. The U mark indicates the mean response to uncorrelated RDS. C, The time-averaged vergence angle of the stimulation duration with respect to the prestimulus period is plotted as a function of horizontal disparity of the stimulus. Error bars represent the mean ± SD.
- Figure 3.
Horizontal disparity tuning curves and the fitted Gabor functions for four additional cells. The other conventions are the same as seen in Figure 2. The amplitude ratios for these cells are 0.07, 0.15, 0.46, and 0.43, respectively.
- Figure 4.
Disparity discriminability across the whole population of V4 cells analyzed (n = 115). The center panel depicts a scatter plot of DDI to cRDS on the horizontal axis and DDI to aRDS on the vertical axis. Cells displaying statistically significant disparity modulation to cRDS are plotted in black (Kruskal-Wallis; p < 0.05). The dashed diagonal line indicates the level of no difference in disparity discriminability regardless of whether the RDS is correlated or anticorrelated. The top and right histograms exhibit the distribution of DDI from the same data set. The top right histogram shows the distribution of DDI differences between correlated and anticorrelated conditions, with positive values representing reduced discriminability to an aRDS.
- Figure 5.
Quality of the Gabor function fit. A, The goodness-of-fit, R2, for cRDS on the horizontal axis and for aRDS on the vertical axis is shown for all cells subject to the Gabor function fit. The dotted lines represent the borders of the criterion, R2 > 0.6, for subsequent data analysis of Gabor function parameters. B, C, Horizontal disparity tuning curves and the fitted Gabor functions of two poorly fit cells are shown. The labeling conventions are the same as seen in Figure 2.
- Figure 6.
Quantitative analysis of the tuning curve profiles. A, Gabor amplitude ratio is plotted against the phase difference between the disparity tunings to cRDS and aRDS for V4 neurons (n=59). The open square indicates where the plot would lie if the responses were perfectly described by the disparity energy model(Ohzawa et al., 1990). The distributions of phase differences and amplitude ratios are plotted in the top and right histograms, respectively. Filled symbols represent cells that have significant disparity sensitivity to both cRDS and aRDS (Kruskal-Wallis test; p < 0.05). B, The same plots for V1 neurons (n = 72) studied by Cumming and Parker (1997).
- Figure 7.
A, The amplitude ratio calculated from the fitted Gabor function is plotted against the modulation ratio calculated from peak-to-trough of the raw mean responses. B, The amplitude of the fitted Gabor function is plotted against the peak-to-trough modulation of the raw mean responses for cRDS disparity tuning. C, The amplitude of the fitted Gabor function is plotted against the peak-to-trough modulation of the raw mean responses for aRDS disparity tuning. D, Histogram of the minimum mean responses to aRDS is plotted.
- Figure 8.
The width of 95% confidence interval of the phase difference is plotted against the estimated value of the phase difference. Data for cells with confidence ranges >2π are plotted on the ceiling. Filled symbols represent cells that have significant disparity sensitivity to both cRDS and aRDS (Kruskal-Wallis test; p < 0.05).
- Figure 9.
Temporal profile of responses of V4 neurons. A, Average normalized PSTHs of cells with tuning curves that were fit to a Gabor function are plotted as a function of time from stimulus onset. Thick solid and thick dashed lines represent the responses to cRDS at preferred and nonpreferred disparities, respectively. Thin solid and thin dotted lines indicate the responses at the same disparities, with anticorrelated RDS. The inset indicates the line styles and the corresponding responses in a disparity tuning curve. B, The amplitude ratio is plotted against the response latency. The population of cells is the same as in A.
