Table 6
L5 pyramidal neuron subtypes differ in electrophysiological and morphological parameters
| Slender tufted | Broad tufted | |||
|---|---|---|---|---|
| High-resistance (n = 13) | Low-resistance (n = 27) | Regular spiking (n = 18) | P | |
| Electrophysiology | ||||
| Ratio ISI-1/ISI-9 | 0.25 ± 0.03 | 0.22 ± 0.01 | 0.22 ± 0.02 | 0.70 |
| Ratio ISI-2/ISI-9 | 0.43 ± 0.05 | 0.46 ± 0.03 | 0.79 ± 0.04** | <0.01 |
| Ratio ISI-3/ISI-9 | 0.56 ± 0.06 | 0.65 ± 0.03 | 0.91 ± 0.02** | <0.01 |
| Increase in firing frequency (Hz/100 pA) | 6.4 ± 0.7 | 5.6 ± 0.4 | 6.4 ± 0.2 | 0.27 |
| Membrane potential (mV) | -65.5 ± 0.09 | -67.4 ± 0.6 | -64.0 ± 0.7 | <0.01 |
| Input resistance (MΩ) | 255 ± 20** | 145 ± 6** | 90 ± 5** | <0.01 |
| Rheobase (pA) | 66 ± 4** | 124 ± 7** | 179 ± 10** | <0.01 |
| Time constant (ms) | 40.1 ± 2.4** | 31.9 ± 1.3** | 21.2 ± 1.0** | <0.01 |
| Voltage sag (%) | 13.1 ± 1.9 | 14.7 ± 1.5 | 23.8 ± 1.7** | <0.01 |
| Morphology | ||||
| Location in L5 (%) | 34 ± 6 | 30 ± 4 | 38 ± 4 | 0.50 |
| Field span apical dendrites (μm) | 307 ± 31 | 288 ± 19 | 482 ± 24** | <0.01 |
| Field span basal dendrites (μm) | 403 ± 60 | 394 ± 10 | 325 ± 9 | 0.07 |
| Total length apical dendrites (μm) | 3346 ± 462 | 3187 ± 113 | 6530 ± 310** | <0.01 |
| Total length basal dendrites (μm) | 3271 ± 219** | 5260 ± 224 | 4580 ± 220 | <0.01 |
| Soma (μm2) | 301 ± 18 | 298 ± 11 | 367 ± 19** | <0.01 |
| Number of apical branches | 19.2 ± 2.2 | 17.7 ± 0.7 | 37.7 ± 1.9** | <0.01 |
| Number of basal branches | 21.3 ± 1.7** | 31.0 ± 1.2* | 36.8 ± 1.7** | <0.01 |
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Note: For clarity, the results of the post hoc comparison of groups is only given (values in bold followed with asterisks) when a cell type is different from all other cell types. *P < 0.05, **P < 0.01.