Color and orientation are jointly coded and spatially organized in primate primary visual cortex

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Science  28 Jun 2019:
Vol. 364, Issue 6447, pp. 1275-1279
DOI: 10.1126/science.aaw5868
  • Fig. 1 In vivo GCaMp6f two-photon calcium imaging in primate V1.

    (A) Schematic of experimental setup (see supplementary materials and methods). (B) Average fluorescence of one imaging region after presentation of colored drifting gratings. Four cells are indicated and their corresponding traces are shown in (C). Scale bar: 200 μm. (C) Sample fluorescence traces, indicated by the color of the stimulus to which they responded most strongly. Colored bars indicate the hue of the stimulus displayed at each time point.

  • Fig. 2 Orientation-selective, hue-selective, and color-preferring neurons in primate V1.

    (A) Aligned CO histology for two-photon imaging region in (B to D) (see fig. S2). Contours demonstrate normalized CO intensity. Scale bar: 200 μm. (B) The location of each visually responsive neuron is plotted. Neurons are colored according to their CPI. This figure contains two superimposed cortical imaging depths. Color scale (bottom) for CPI values. (C) Same region as (B), with the color of individual neurons plotted on the basis of each neuron’s OSI in response to its preferred stimulus. Color scale (bottom) for OSI values. (D) Neurons considered hue selective are labeled by their preferred hue, whereas neurons that were visually responsive but not hue selective are depicted in gray. Color bar (bottom) showing presented hues. (E to H) Same as (A to D), for a second imaging region. Cells 1 to 5 depicted in (I to R) are indicated with arrows. Scale bar: 200 μm. (I to M) Mean (± SEM) change in fluorescence to 12 hues at each neuron’s preferred orientation and spatial frequency. The response to achromatic gratings at each neuron’s preferred orientation and spatial frequency is plotted in black. (N to R) Average change in fluorescence to eight stimulus directions at each neuron’s preferred hue (or achromatic) and spatial frequency.

  • Fig. 3 Population statistics demonstrating mutual representation of color and orientation.

    (A) Relationship between CPI and OSI for all cells. Neurons above the horizontal dashed line responded at least twice as strongly to their preferred versus orthogonal orientation (OSI > 0.5). Vertical dashed lines represent CPI = −0.33 and 0.33 (neurons responded twice as strongly to achromatic or equiluminant colored stimuli, respectively). (B) Relationship between CO intensity and OSI. Trend line fit using least-squares linear regression. r, correlation coefficient. (C) Same as (C), for CO intensity versus CPI. (D) Histograms of neurons in each region of (A), based on CO intensity. Because of geometric considerations, the numbers of cells sampled are not equal in each bin. The actual sampling distributions are shown in fig. S2G.

  • Fig. 4 Spatial organization of hue selectivity and relationship to CO histology.

    (A) Histogram of distance between simultaneously recorded cell pairs and correlation coefficient of their hue-tuning curves. Black circles indicate the average of all points in 25-μm bins and gray circles indicate the average of all points when shuffled. (B to E) Histograms of the number of green (B), blue (C), red (D), and non-hue-selective (E) neurons based on CO intensity. Dashed lines indicate the median of each distribution. (F) Mean (± SEM) OSIs for cells that prefer red, green, and blue hues, and neurons that are not hue selective but are visually responsive to achromatic stimuli (gray). *P = 0.002; ***P < 0.001. Populations of included red, green, blue, and non-hue-selective neurons are indicated with asterisks in fig. S3C.

Supplementary Materials

  • Color and orientation are jointly coded and spatially organized in primate primary visual cortex

    Anupam K. Garg, Peichao Li, Mohammad S. Rashid, Edward M. Callaway

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Supplementary Text
    • Figs. S1 to S8
    • Table S1
    • Caption for Movie S1
    • References

    Images, Video, and Other Media

    Movie S1
    Averaged two-photon imaging responses to colored stimuli. (A) Example imaging region showing averaged live responses to stimuli of various hues, shown in the left corner. White hue represents average response to blank trials. Scale bar: 200μm. (B) Zoomed portion of imaging region in A, defined with white boundary box. Sample cells in C and D indicated with blue and green circles, respectively. Scale bar: 200μm. (C to D) Responses of two example neurons shown in B. Gray region indicates period during which stimulus was presented.

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