Table 1.
Model parameters | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Model | Gain of sensory response (g) | Response to stimulus noise (kn) | Strength of divisive normalization (ks) | (Population) Fano factor (kv) | Fixed variance | Offset | (Effective) integration time constant (ms; τ or τeff) | Decision threshold | Residual time (ms; tres) | Remaining error after mean RT fit | Percentage of predicted choice data points within 95% confidence intervals | Quality of RT distribution match: mean intersection/mean fidelity |
Slightly leaky feedforward inhibition model (Figure 1) | 0.0101 | 0.120 | 2.01 | 0.332 | N/A | N/A | 714 (imposed; chosen to match feedback inhibition model) | 1 (imposed) | 353 | 97 (49) | 87 | 0.858/0.984 |
Very leaky feedforward inhibition model (Figure 2) | 0.0315 | 0.135 | 1.83 | 0.675 | N/A | N/A | 50 (imposed) | 1 (imposed) | 477 | 80 (50) | 83 | 0.822/0.926 |
Feedback inhibition (LCA) model with scaling variance (Figure 4) | 0.0117 | 0.0928 | 2.78 | 0.417 | N/A | N/A | 714(b = 0.00140 for a time unit of 1 ms) | 1 (imposed) | 404 | 84 (75) | 65 | 0.829/0.935 |
Feedback inhibition (LCA) model with fixed variance (Figure 5) | 0.0131 | 0.0967 | 2.29 | N/A | 0.000407 | N/A | 694(b = 0.00144 for a time unit of 1 ms) | 1 (imposed) | 392 | 61 (44) | 74 | 0.751/0.920 |
Feedforward MSPRT model (Figure 6) | 0.0192 | 0.0975 | 2.08 | 0.434 | N/A | N/A | ∞ (imposed) | −0.383 | 390 | 92 (65) | 61 | 0.773/0.928 |
Feedback MSPRT model (Figure 8) | 0.0174 | 0.101 | 2.19 | 0.696 | N/A | 1.47 | ∞ (imposed) | 1 (imposed) | 447 | 81 (69) | 57 | 0.841/0.926 |
Parameters in bold have been determined through optimization. The first number in the “Remaining error” column indicates the remaining error after a high-resolution simulation (50,000 trials per experimental condition) of the model with the indicated parameter set. The second number in brackets indicates the smallest error that was seen during the optimization process based on a lower-resolution simulation (10,000 trials per condition).