Table 2.
Typical results from individual differences simulations.
| Parameter varying (and location in Figure 3) | Parameter mean (population, [sample]) | Parameter SD (population, [sample]) | Simulation output, sample mean | Simulation output, sample SD | Correlation (parameter, simulation output) |
|---|---|---|---|---|---|
| AFFECTING MODEL EXCITATORY PATHWAYS | |||||
| wPD (1) | 5 [5.116] | 1 [1.003] | 0.225 | 0.052 | 0.98 |
| wPD* (1) | 5 [4.838] | 1 [0.824] | 0.214 | 0.041 | 0.95 |
| wSP (5) | 2 [2.058] | 0.5 [0.501] | 0.230 | 0.080 | 0.98 |
| w‡SP (5) | 2.125 [2.125] | Range 0.25–4.0 | 0.239 | 0.156 | 0.99 |
| wRP (6) | 0.8 [0.823] | 0.2 [0.201] | 0.228 | 0.011 | 0.91 |
| w‡RP (6) | 2.05 [2.05] | Range 0.1–4.0 | 0.269 | 0.041 | 0.97 |
| wRS (7) | 1.5 [1.540] | 0.35 [0.351] | 0.216 | 0.020 | 0.59† |
| w‡RS (7) | 1.05 [1.05] | Range 0.1–2.0 | 0.165 | 0.069 | n/a |
| wmaxs | 1.0 [1.029] | 0.25 [0.251] | 0.225 | 0.042 | 0.92 |
| τWS (4) | 1 [1.028] | 0.25 [0.25] | 0.219 | 0.007 | 0.765 |
| τWS** (4) | 20 [20.56] | 5.0 [5.0] | 0.293 | 0.014 | 0.90 |
| βWS (4) | 0.5 [0.515] | 0.125 [0.125] | 0.216 | 0.002 | −0.20† |
| AFFECTING MODEL INHIBITORY PATHWAYS | |||||
| hD (2) | 6 [6.1155] | 1 [1.0025] | 0.217 | 0.005 | −0.86 |
| γS (3) | 100 [102.309] | 20 [20.050] | 0.217 | 0.006 | −0.86 |
| αZ (3) | 0.05 [0.0514] | 0.0125 [0.0125] | 0.218 | 0.007 | −0.80 |
Parameter symbols are as in Brown et al. (1999); SD = standard deviation. n/a not appropriate. Samples are of 50 simulated individuals. Population values for parameters are the values of the random normal variables specified in the simulating program. The same sample of standard random normal values was used in each simulation but was scaled to give the appropriate SD for the parameter, as reported above. Simulations for parameters marked with an
used a different sample of random normal values; those for parameters marked
were for a larger mean value, matching that used in the original paper; and those for parameters marked with a
used a uniformly spaced set of parameter values, covering the specified range. Correlations marked with a
should be treated cautiously as clear, non-linearities were observed. Simulation output = change in normalized DA firing rate between UR and UNR trials, in DA spikes per 20 ms recording bin.