A quadratic model captures the human V1 response to variations in chromatic direction and contrast
- Department of Psychology, University of Pennsylvania, United States
- Department of Neurology, University of Pennsylvania, United States
Figures
Figure 1
Quadratic color model.
(A) The LM contrast plane representing two example stimuli (c1 and c2) as the green and yellow vectors. The vector length and direction specify the contrast and chromatic direction of the positive …
Figure 2 with 2 supplements
V1 contrast response functions for the eight measured chromatic directions from Subject 2.
Each panel plots the contrast response function of V1, aggregated over 0° to 20° eccentricity, for a single chromatic direction. The x-axis is contrast, the y-axis is the BOLD response (taken as the …
Figure 2—figure supplement 1
V1 contrast response functions for the eight measured chromatic directions from Subject 1.
The format of the figure is the same as Figure 2 in the main text. The x-axis is contrast; the y-axis is the beta weight of the GLM. The chromatic direction of each stimulus is indicated in the …
Figure 2—figure supplement 2
V1 contrast response functions for the eight measured chromatic directions from Subject 3.
The format of the figure is the same as Figure 2 in the main text and Figure 2—figure supplement 1.
Figure 3 with 3 supplements
Model fits to the V1 BOLD time course.
The measured BOLD time course (thin gray line) is shown along with the model fits from the QCM (thick purple line) and GLM (thin orange line) for six runs from Subject 2. Individual runs consisted …
Figure 3—figure supplement 1
Model fits to the V1 BOLD time course from Subject 1.
The format of the Figure is the same as Figure 3 in the main text. The measured BOLD time course (black line) is shown along with the model outputs from the QCM (thick purple line) and GLM (thin …
Figure 3—figure supplement 2
Model fits to the V1 BOLD time course from Subject 3.
The format of the figure is the same as Figure 3 in the main text and Figure 3—figure supplement 1 The measured BOLD time course (black line) is shown along with the model outputs from the QCM …
Figure 3—figure supplement 3
Mean Residuals for the QCM and the GLM.
Each panel shows the mean model residual for both the QCM (purple) and the GLM (orange) as a function of the chromatic direction. The mean of the model residuals is taken from 4 to 14 TRs after …
Figure 4 with 1 supplement
Cross-validated model comparison for the QCM and the GLM, from the V1 ROI and for all three subjects.
In each panel, the mean leave-one-out cross-validated R2 for the QCM (purple bars) and the GLM (orange bars). These values are displayed at the top of each panel. Within each panel, the left group …
Figure 4—figure supplement 1
Cross-validated model comparison for all models, from the V1 ROI.
The rows show data for each subect and columns are the different measument sets. In each panel, we plot the mean leave-one-out cross-validated R2 (from left to right) for the General Linear Model, …
Figure 5 with 3 supplements
Leave-sessions-out cross validation.
The contrast response functions in each panel (green lines) are the result of a leave-sessions-out cross-validation to test the generalizability of the QCM. The QCM was fit to data from four out of …
Figure 5—figure supplement 1
Leave-sessions-out cross validation for Subject 1.
The format of the Figure is the same as Figure 5 in the main text. The contrast response functions in each panel (green lines) are the result of a leave-sessions-out cross-validation to test the …
Figure 5—figure supplement 2
Leave-sessions-out cross validation for Subject 2.
The format of the figure is the same as Figure 5 in the main text and Figure 5—figure supplement 1. The contrast response functions in each panel (green lines) are the result of a leave-sessions-out …
Figure 5—figure supplement 3
Leave-sessions-out cross validation for Subject 3.
The format of the figure is the same as Figure 5 in the main text and Figure 5—figure supplements 1–2. The green lines are the leave-session-out CRF, and the orange points are the GLM fits to the …
Figure 6 with 1 supplement
V1 isoresponse contours.
The normalized elliptical isoresponse contours from the QCM are plotted, for each subject, in the LM contrast plane. The green ellipses show the QCM fits to Measurement Set 1 and the purple ellipses …
Figure 6—figure supplement 1
Isoresponse Contours for the LCM and the QCM.
Each panel shows the isoresponse contours derived using the LCM with both the Brouwer and Heeger, 2009 variant (green) and the Kim et al., 2020 (dark orange). These are shown along with the …
Figure 7 with 1 supplement
Equivalent contrast non-linearities of the QCM for V1 from Subject 2.
The x-axis of each panel marks the equivalent contrast and the y-axis is the neuronal response. The gray curve in each panel is the Naka-Rushton function obtained using the QCM fit. These curves …
Figure 7—figure supplement 1
Equivalent Contrast Non-Linearities of the QCM for V1.
The format is the same as Figure 7 in the main text. The x-axis of each panel marks the equivalent contrast and the y-axis is the response. The gray curve in each panel is the Naka-Rushton function …
Figure 8 with 1 supplement
QCM average parameter maps.
The QCM parameters, fit at all vertices within the visual cortex mask, averaged across all subjects and measurement sets. The top, middle, and bottom rows show maps of the average ellipse angle, …
Figure 8—figure supplement 1
Average R2 map for the GLM for early visual cortex.
The format is the same as the bottom row of Figure 8 in the main text. This show the R2 values for the GLM fit to each vertex within the EVC mask averaged across all subjects and sessions. The color …
Figure 9 with 2 supplements
QCM parameters as a function of eccentricity for Subject 2.
The left and right panels show scatter plots of the minor axis ratio and ellipse angle plotted against their visual field eccentricity, respectively. Each point in the scatter plot shows a parameter …
Figure 9—figure supplement 1
L+M and L-M responses predicted using QCM as a function of eccentricity.
The top row shows responses for Subject 1, the middle row show responses for Subject 2, and the bottom row shows responses for Subject 3. The left and right panels show data from Measurement Set 1 …
Figure 9—figure supplement 2
QCM parameters as a function of eccentricity.
The format is the same as Figure 9 in the main text. The top row shows parameter fits from Subject 1 and the bottom row shows fits from Subject 3. The left and right panels show scatter plots of the …
Figure 10
Stimulus space and temporal modulations.
(A) The LM contrast plane. A two-dimensional composed of axes that represent the change in L- and M-cone activity relative to the background cone activation, in units of cone contrast. Each aligned …
Figure 11
Experimental design.
Panels A and B show the block design used for all runs and sessions. Panel A shows Measurement Set 1 which contained two separate MRI sessions. Each session contained four of the eight chromatic …
Appendix 1—figure 1
Illustration of cone to equivalent contrast transformation.
(Panel A) A 3-dimensional cone contrast-response space with the (,) plane representing the LM contrast plane and the axis giving the corresponding response to each point in the (,) …
Author response image 1
Tables
Table 1
Robust regression line parameters summarizing the change in minor axis ratio with eccentricity for all subjects.
These parameters are the same as seen for Subject 2 in Figure 9. The subject and set columns indicate the subject and measurement set of the robust regression fit. The slope and offset column show …
| Subject | Set | Slope | Offset | ∆ 0° to 20° | ∆ Set to Set |
|---|---|---|---|---|---|
| S1 | 1 | −1.19e-3 | 0.163 | 0.0238 | 0.09 |
| S1 | 2 | −4.17e-4 | 0.24 | 0.0084 | |
| S2 | 1 | −7.54e-6 | 0.154 | 0.0002 | 0.00 |
| S2 | 2 | −2.51e-3 | 0.183 | 0.0504 | |
| S3 | 1 | −3.27e-3 | 0.114 | 0.0654 | 0.03 |
| S3 | 2 | −3.9e-4 | 0.158 | 0.0078 |
Table 2
Robust regression line parameters summarizing the change in ellipse angle with eccentricity for all subjects.
Columns are formatted the same as Table 1.
| Subject | Set | Slope | Offset | ∆ 0° to 20° | ∆ Set to Set |
|---|---|---|---|---|---|
| S1 | 1 | 0.039 | 46.2 | 0.78 | 2.61 |
| S1 | 2 | 0.313 | 41.4 | 6.26 | |
| S2 | 1 | 0.496 | 39.5 | 9.92 | 3.76 |
| S2 | 2 | 0.330 | 45.1 | 6.60 | |
| S3 | 1 | 0.247 | 39.3 | 4.94 | 5.62 |
| S3 | 2 | 0.425 | 43.3 | 8.50 |
Table 3
Table of the nominal maximum contrast per direction.
The top row indicates the chromatic direction in the LM plane.The L, M, and S contrast rows show the desired contrast on the L, M, and S cones, respectively. The total contrast is the vectorlength …
| Direction | −45° | −22.5° | 0° | 22.5° | 45° | 67.5° | 90° | 112.5° |
|---|---|---|---|---|---|---|---|---|
| L-Contrast | 8.49% | 7.85% | 14% | 18.48% | 42.43% | 15.31% | 0% | 4.98% |
| M-Contrast | 8.49% | 3.25% | 0% | 7.65% | 42.43% | 36.96% | 22% | 12.01% |
| S-Contrast | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% |
| Total Contrast | 12% | 8.5% | 14% | 20% | 60% | 40% | 22% | 13% |
Table 4
Number of censored fMRI frames per run.
Values shown are for Subject 1 Measurement Set 2. The top set of rows show data for session one and the bottom set of the show data for session 2. Each set of rows show the number of censored frames …
| Subject 1 – Measurement Set 2: Session 1 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Run Number | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| Number of Censored Frames (n/360) | 0 | 0 | 8 | 18 | 0 | 26 | 47 | 4 | 0 | 0 |
| Subject 1 – Measurement Set 2: Session 2 | ||||||||||
| Run Number | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| Number of Censored Frames (n/360) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7 | 0 | 0 |
Table 5
Stimulus validation measurements for Subject 1.
The top set of rows show data for Measurement Set 1 and the bottom set show data for Measurement Set 2. The dark gray rows show the nominal angle and contrast. Each cell shows the mean and standard …
| Subject 1 – Measurement Set 1 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Nominal Angle | −45° | −22.5° | 0° | 22.5° | 45° | 67.5° | 90° | 112.5° |
| Center Angle | −41.23 ±3.13 | −15.90 ±6.59 | 2.17 ±1.05 | 23.43 ±0.23 | 45.21 ±0.23 | 69.36 ±1.61 | 87.98 ±1.26 | 120.94 ±8.45 |
| Periphery Angle | −42.85 ±3.04 | −16.31 ±6.18 | 1.61 ±0.44 | 22.75 ±0.22 | 44.78 ±0.22 | 68.13 ±1.54 | 88.72 ±0.18 | 119.67 ±8.04 |
| Nominal Contrast | 12% | 8.5% | 14% | 20% | 60% | 40% | 22% | 13% |
| Center Contrast | 12.14 ±0.05 | 9.02 ±0.75 | 14.44 ±0.37 | 21.05 ±0.79 | 60.92 ±0.09 | 38.01 ±1.97 | 21.39 ±0.85 | 12.56 ±0.38 |
| Periphery Contrast | 12.00 ±0.04 | 8.93 ±0.72 | 13.98 ±0.35 | 20.28 ±0.73 | 58.73 ±0.09 | 37.81 ±1.89 | 21.42 ±0.55 | 12.48 ±0.36 |
| Subject 1 - Measurement Set 2 | ||||||||
| Nominal Angle | −45° | −22.5° | 0° | 22.5° | 45° | 67.5° | 90° | 112.5° |
| Center Angle | −45.09 ±0.55 | −22.44 ±0.98 | 3.49 ±2.27 | 22.97 ±0.15 | 45.18 ±0.03 | 67.75 ±0.24 | 87.81 ±1.69 | 112.99 ±1.03 |
| Periphery Angle | −46.16 ±0.55 | −22.32 ±0.99 | 3.24 ±2.77 | 22.39 ±0.19 | 44.92 ±0.02 | 66.85 ±0.21 | 87.33 ±1.24 | 68.34 ±0.92 |
| Nominal Contrast | 12% | 8.5% | 14% | 20% | 60% | 40% | 22% | 13% |
| Center Contrast | 11.75 ±0.01 | 8.28 ±0.08 | 13.78 ±0.09 | 20.35 ±0.22 | 60.26 ±0.48 | 37.62 ±0.11 | 21.82 ±0.08 | 12.69 ±0.05 |
| Periphery Contrast | 11.65 ±0.02 | 8.29 ±0.08 | 13.53 ±0.09 | 19.79 ±0.18 | 58.47 ±0.48 | 38.16 ±0.10 | 21.99 ±0.10 | 12.81 ±0.06 |
Table 6
Stimulus validation measurements for Subject 2.
The format of this table is the same as Table 5. Cells that contain an 'X' mark stimulus directions in which validation measurements were not recorded due to technical difficulty.
| Subject 2 - Measurement Set 1 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Nominal Angle | −45° | −22.5° | 0° | 22.5° | 45° | 67.5° | 90° | 112.5° |
| Center Angle | −45.73 ±1.06 | −19.23 ±2.51 | 1.71 ±0.98 | 24.04 ±0.39 | 45.43 ±0.09 | 68.36 ±0.53 | 87.87 ±1.64 | 114.92 ±1.90 |
| Periphery Angle | −47.03 ±1.02 | −18.91 ±2.40 | 1.63 ±0.77 | 23.65 ±0.38 | 44.99 ±0.09 | 67.18 ±0.52 | 87.65 ±1.09 | 114.11 ±1.86 |
| Nominal Contrast | 12% | 8.5% | 14% | 20% | 60% | 40% | 22% | 13% |
| Center Contrast | 12.04 ±0.11 | 8.41 ±0.21 | 14.01 ±0.08 | 20.45 ±0.52 | 60.72 ±0.38 | 39.68 ±0.63 | 21.82 ±0.23 | 12.73 ±0.16 |
| Periphery Contrast | 11.88 ±0.11 | 8.36 ±0.21 | 13.58 ±0.07 | 19.81 ±0.51 | 58.56 ±0.35 | 39.41 ±0.59 | 21.82 ±0.24 | 12.62 ±0.14 |
| Subject 2 - Measurement Set 2 | ||||||||
| Nominal Angle | −45° | −22.5° | 0° | 22.5° | 45° | 67.5° | 90° | 112.5° |
| Center Angle | X | −25.85 ±3.20 | X | 22.72 ±0.38 | X | 67.42 ±0.16 | X | 112.03 ±1.22 |
| Periphery Angle | X | −26.43 ±3.04 | X | 22.35 ±0.35 | X | 66.36 ±0.16 | X | 110.12 ±1.17 |
| Nominal Contrast | 12% | 8.5% | 14% | 20% | 60% | 40% | 22% | 13% |
| Center Contrast | X | 8.36 ±0.16 | X | 19.77 ±0.23 | X | 39.75 ±0.13 | X | 12.75 ±0.15 |
| Contrast | X | 8.34 ±0.17 | X | 19.21 ±0.23 | X | 40.04 ±0.15 | X | 12.95 ±0.13 |
Table 7
Stimulus validation measurements for Subject 3.
| Subject 3 - Measurement Set 1 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Nominal Angle | −45° | −22.5° | 0° | 22.5° | 45° | 67.5° | 90° | 112.5° |
| Center Angle | −48.84 ±5.02 | −27.84 ±6.02 | 5.29 ±4.45 | 23.61 ±0.77 | 45.41 ±0.15 | 67.48 ±0.42 | 85.96 ±3.11 | 108.56 ±4.89 |
| Periphery Angle | −50.40 ± 4.90 | −28.48 ±5.97 | 5.09 ±4.72 | 23.26 ±0.77 | 45.02 ±0.13 | 66.33 ±0.43 | 86.12 ±3.24 | 107.49 ±4.78 |
| Nominal Contrast | 12% | 8.5% | 14% | 20% | 60% | 40% | 22% | 13% |
| Center Contrast | 12.25 ±0.32 | 8.39 ±0.06 | 13.96 ±0.08 | 19.78 ±0.20 | 61.92 ±1.40 | 40.87 ±1.14 | 22.91 ±1.30 | 13.53 ±0.75 |
| Periphery Contrast | 12.13 ±0.31 | 8.30 ±0.08 | 13.52 ±0.09 | 19.17 ±0.21 | 59.76 ±1.36 | 40.65 ±1.13 | 22.97 ±1.26 | 13.47 ±0.71 |
| Subject 3 - Measurement Set 2 | ||||||||
| Nominal Angle | −45° | −22.5° | 0° | 22.5° | 45° | 67.5° | 90° | 112.5° |
| Center Angle | X | −24.51 ±1.57 | X | 22.92 ±0.07 | X | 67.65 ±0.19 | X | 111.23 ±1.11 |
| Periphery Angle | X | −24.17 ±1.53 | X | 22.65 ±0.06 | X | 66.57 ±0.19 | X | 69.95 ±1.07 |
| Nominal Contrast | 12% | 8.5% | 14% | 20% | 60% | 40% | 22% | 13% |
| Center Contrast | X | 8.24 ±0.07 | X | 19.93 ±0.09 | X | 39.77 ±.0.27 | X | 12.88 ±0.11 |
| Periphery Contrast | X | 8.23 ±0.07 | X | 19.45 ±0.26 | X | 40.16 ±0.26 | X | 12.92 ±0.10 |
