Table 2.
Characteristics of Responses to Mossy Fiber and Perforant Path Stimulation.
| Pathway | Genotype | Stim Intensity V50 (µA) |
Maximum Response |
PPR (%) |
n (slices, electrodes) |
|---|---|---|---|---|---|
| MF – CA3sl | |||||
| fEPSP slope | WT | 80.3 ± 3.5 | 217 ± 10 (µV/ms) | 118.2 ± 11.4 | 5, 21 |
| KO | 65 ± 3.1b | 366 ± 22 (µV/ms) c | 66.8 ± 5.3 c | 7, 28 | |
| FV amplitude | WT | 59.6 ± 3.2 | 223 ± 15 (µV) | 3, 7 | |
| KO | 41.4 ± 2.2 b | 507 ± 17 (µV) c | 5, 13 | ||
| MPP – DGml | |||||
| fEPSP slope | WT | 53.2 ± 3 | 699 ± 97 (µV/ms) | −7.4 ± 1.7 | 9, 19 |
| KO | 41.3 ± 3a | 1606 ± 109 (µV/ms) c | −17.5 ± 1.7 c | 12, 30 | |
| FV amplitude | WT | 66.9 ± 7.2 | 434 ± 44 (µV) | 6, 13 | |
| KO | 47.9 ± 2.2 b | 777 ± 63 (µV) b | 3, 9 | ||
| MPP – CA3sr | |||||
| fEPSP slope | WT | 57.5 ± 4 | 284 ± 14 (µV/ms) | −9.6 ± 2.9 | 5, 13 |
| KO | 38 ± 2c | 444 ± 28 (µV/ms) b | −19.9 ± 3 c | 9, 21 | |
| LPP – DGml | |||||
| fEPSP slope | WT | 71.3 ± 4.3 | 932 ± 101 (µV/ms) | 36.4 ± 2.9 | 7, 23 |
| KO | 68.3 ± 3.7 | 893 ± 79 (µV/ms) | 36.6 ± 4.8 | 7, 21 | |
| LPP – CA3sr | |||||
| fEPSP slope | WT | 76.9 ± 3.4 | 552 ± 85 (µV/ms) | 33.9 ± 2.4 | 5, 9 |
| KO | 81.4 ± 5.7 | 422 ± 80 (µV/ms) | 34.6 ± 8.4 | 5, 9 |
Stimulation intensity V50’s were determined by fitting normalized data with a Boltzmann equation. The paired pulse ratio represents the percent a second response is greater or lower than a first response evoked by two stimulations (50 ms ISI; 50% intensity). Abbreviations: FV, presynaptic fiber volley; MF, mossy fiber; MPP, medial perforant path; LPP, lateral perforant path; DG, dentate gyrus; ml, molecular layer; sl, stratum lacunosum; sr, stratum radiatum; PPR, paired pulse ratio. Data presented as mean ± SEM. Comparison of WT vs. KO using the number of slices for the n
a
p<0.05;
b
p<0.01;
c
p<0.001.