Table 4. Investigation of the Non-Social (ns1–ns3) and Social Stimuli (s1–s6) During Extinction in Relation to Over Night Exposure to the Empty Cage and Exposure to Non-Social Stimuli During Extinction.
| Non-social (ns) and social (s) investigation | ns1 | ns2 | ns3 | s1 | s2 | s3 | s4 | s5 | s6 |
|---|---|---|---|---|---|---|---|---|---|
| 1. Without over night extinction of fear of the empty cage | |||||||||
| 1.1. Without previous non-social exposure | |||||||||
| Unconditioned mice (n=9) | 42.3±8.3 | 75.0±5.8 | 77.0±3.2 | 69.8±4.7 | 69.4±4.7 | 66.2±3.7 | |||
| Conditioned mice (n=9) | 0.3±0.2* | 1.7±1.2* | 1.8±1.0* | 1.2±0.5* | 3.7±1.3* | 5.6±2.4* | |||
| 1.2. With previous non-social exposure | |||||||||
| Unconditioned mice (n=6) | 27.0±10.2 | 40.1±16.2 | 44.4±16.3 | 66.3±11.1 | 78.4±3.8 | 71.0±11.5 | 72.7±9.7 | 72.5±9.5 | 79.7±5.1 |
| Conditioned mice (n=6) | 0.8±0.4* | 0.6±0.4* | 1.3±0.7* | 1.2±0.5* | 2.7±1.3* | 1.7±1.1* | 2.6±1.6* | 2.4±1.6* | 3.2±1.3* |
| 2. With over night extinction of fear of the empty cage | |||||||||
| 2.1. Without previous non-social exposure | |||||||||
| Unconditioned mice (n=8) | 72.4±7.7 | 80.7±3.0 | 85.8±3.0 | 81.1±3.0 | 82.0±4.0 | 79.7±5.1 | |||
| Conditioned mice (n=9) | 5.3±3.2* | 18.7±9.5* | 32.0±11.9* | 37.7±12.5* | 40.7±13.2* | 3.2±1.3* | |||
| 2.2. With previous non-social exposure | |||||||||
| 2.2.1. Short-term social fear (Figure 1) | |||||||||
| Unconditioned mice (n=13) | 38.7±3.8 | 13.5±2.5 | 12.5±3.6 | 71.2±4.7 | 83.3±1.7 | 73.1±5.0 | 71.8±6.3 | 71.0±5.7 | 68.8±7.9 |
| Conditioned mice (n=13) | 32.4±5.6 | 21.2±7.1 | 7.5±2.0 | 13.1±6.3* | 35.9±9.9* | 42.8±9.5* | 48.0±8.7* | 56.2±8.9 | 42.0±8.0* |
| 2.2.2. Short-term social fear by diazepam (Figure 6) | |||||||||
| Unconditioned mice (n=10) | 44.4±3.4 | 16.2±4.5 | 10.2±4.2 | 52.6±7.7 | 69.7±8.4 | 67.5±8.3 | 68.0±5.4 | 62.8±6.1 | 72.9±3.8 |
| Conditioned mice (n=10) | 33.3±6.7 | 17.6±5.6 | 11.1±3.7 | 8.8±4.4* | 25.4±8.8* | 27.0±9.6* | 23.3±9.4* | 31.2±8.6 | 30.4±9.3* |
| 2.2.3. Long-term social fear (Figure 2) | |||||||||
| Unconditioned mice (n=9) | 46.8±10.2 | 48.3±10.6 | 37.7±8.7 | 73.5±8.0 | 75.9±7.0 | 79.3±3.6 | 77.6±5.1 | 76.8±4.7 | 75.7±3.7 |
| Conditioned mice (n=9) | 48.2±8.3 | 39.3±8.0 | 28.0±6.8 | 15.3±9.9* | 28.5±11.5* | 35.9±12.4* | 41.4±13.2* | 39.0±12.5* | 38.8±12.4* |
| 2.2.4. Long-term social fear by paroxetine (Figure 7) | |||||||||
| Unconditioned mice (n=8) | 31.2±4.1 | 25.8±6.7 | 8.5±1.9 | 83.0±2.1 | 90.5±2.7 | 88.6±2.9 | 88.5±2.1 | 85.8±3.7 | 83.8±2.6 |
| Conditioned mice (n=8) | 18.8±3.9 | 10.7±4.6 | 6.9±2.0 | 5.2±5.1* | 10.8±6.7* | 22.2±9.0* | 34.7±8.8* | 43.6±8.5* | 51.7±7.9* |
Mice were social fear conditioned and the empty cage was either placed or not in their home cage over night. Extinction was assessed 1 day or 15 days later. Data represent mean percentage of investigation time ±SEM.
*p<0.05 vs unconditioned mice. Statistical significance shown in points 2.2.2. and 2.2.4. Represents those from all treatment groups, as shown in the results section.