Table 2. Parameter Values with 95% Confidence Limits in Parentheses and %VAF From Best Fits of the Hyperbolic Decay Equation to Response Rates as Proportion of Control Response Rate Across Sessions of Extinction Without Food Presentations and Extinction with Response-Independent Food Presentations.
| Genotype | Extinction without food presentations | Extinction with response-independent food presentations | ||
|---|---|---|---|---|
| k parameter | %VAF | k parameter | %VAF | |
| D2R WT | 3.91 (3.01–4.82) | 99.3 | 0.255 (0.188–0.323) | 90.9 |
| D2R KO | 0.585a (0.399–0.771) | 92.1 | 0.121a (0.053–0.137) | 68.9 |
| D3R WT | 1.49 (0.836–2.14) | 92.9 | 0.082 (0.027–0.137) | 35.0 |
| D3R KO | 2.36 (1.41–3.31) | 96.3 | 0.086 (0.047–0.124) | 45.6 |
| D4R WT | 0.895 (0.721–1.07) | 97.1 | 0.242 (0.154–0.331) | 77.1 |
| 2.80b (1.92–3.68) | 97.8 | |||
| D4R KO | 2.16 (1.44–2.89) | 96.4 | 0.162 (0.091–0.233) | 68.0 |
Abbreviations: KO, knockout; %VAF, percentage of variance accounted for; WT, wild type.
a
Significant difference from parameter value in WT littermate subjects.
b
Fit obtained after excluding one D4R WT subject that exhibited increases in responding above control rates for the first three sessions of extinction (all other D4R WT subjects exhibited decreases in responding relative to control rates).