Table 2Excitatory Synaptic Connectivity and uEPSP Amplitudes in the Mouse C2 Barrel Column
| | Presynaptic |
| Postsynaptic | | L2 | L3 | L4 | L5A | L5B | L6 |
| L2 | P (found/tested) | 9.3% (88/950) | 12.1% (22/182) | 12.0% (25/208) | 4.3% (9/209) | 0.96% (1/104) | 0% (0/50) |
| mean ± SEM | 0.64 ± 0.06 mV | 0.71 ± 0.15 mV | 0.98 ± 0.24 mV | 0.52 ± 0.13 mV | 0.21 mV | |
| median | 0.46 mV | 0.59 mV | 0.58 mV | 0.52 mV | | |
| range | 0.08 – 3.88 mV | 0.04 – 2.67 mV | 0.07 – 5.54 mV | 0.08 – 1.09 mV | | |
| L3 | P (found/tested) | 5.5% (10/183) | 18.7% (96/513) | 14.5% (25/172) | 2.2% (2/89) | 1.8% (3/167) | 0% (0/64) |
| mean ± SEM | 0.44 ± 0.09 mV | 0.78 ± 0.07 mV | 0.58 ± 0.13 mV | 0.67 mV | 0.26 ± 0.08 mV | |
| median | 0.35 mV | 0.48 mV | 0.35 mV | | 0.32 mV | |
| range | 0.09 – 1.02 mV | 0.08 – 2.76 mV | 0.07 – 3.33 mV | 0.15 – 1.19 mV | 0.10 – 0.35 mV | |
| L4 | P (found/tested) | 0.96% (2/208) | 2.4% (4/170) | 24.3% (254/1046) | 0.7% (2/275) | 0.7% (1/137) | 0% (0/94) |
| mean ± SEM | 0.31 mV | 0.36 ± 0.09 mV | 0.95 ± 0.08 mV | 0.48 mV | 0.17 mV | |
| median | | 0.31 mV | 0.52 mV | | | |
| range | 0.18 – 0.45 mV | 0.22 – 0.61 mV | 0.06 – 7.79 mV | 0.22 – 0.74 mV | | |
| L5A | P (found/tested) | 9.5% (20/211) | 5.7% (5/87) | 11.6% (32/276) | 19.1% (178/934) | 1.7% (3/174) | 0.6% (1/160) |
| mean ± SEM | 0.55 ± 0.10 mV | 0.93 ± 0.26 mV | 0.54 ± 0.09 mV | 0.66 ± 0.06 mV | 0.24 ± 0.09 mV | 0.08 mV |
| median | 0.40 mV | 1.09 mV | 0.38 mV | 0.37 mV | 0.19 mV | |
| range | 0.08 – 2.03 mV | 0.08 – 1.54 mV | 0.06 – 1.98 mV | 0.05 – 5.24 mV | 0.11 – 0.41 mV | |
| L5B | P (found/tested) | 8.3% (9/108) | 12.2% (20/164) | 8.1% (11/136) | 8.0% (14/175) | 7.2% (40/555) | 2% (2/100) |
| mean ± SEM | 0.22 ± 0.04 mV | 1.01 ± 0.24 mV | 0.88 ± 0.25 mV | 0.88 ± 0.36 mV | 0.71 ± 0.19 mV | 0.30 mV |
| median | 0.20 mV | 0.51 mV | 0.44 mV | 0.60 mV | 0.29 mV | |
| range | 0.09 – 0.47 mV | 0.06 – 4.05 mV | 0.07 – 2.61 mV | 0.13 – 5.45 mV | 0.08 – 7.16 mV | 0.12 – 0.48 mV |
| L6 | P (found/tested) | 0% (0/50) | 0% (0/61) | 3.2% (3/93) | 3.2% (5/158) | 7.0% (7/100) | 2.8% (15/532) |
| mean ± SEM | | | 2.27 ± 1.72 mV | 0.28 ± 0.09 mV | 0.49 ± 0.16 mV | 0.53 ± 0.19 mV |
| median | | | 0.96 mV | 0.27 mV | 0.43 mV | 0.26 mV |
| range | | | 0.17 – 5.67 mV | 0.06 – 0.58 mV | 0.14 – 1.36 mV | 0.09 – 3.00 mV |
The probability of finding a synaptically connected pair of neurons with somata of presynaptic and postsynaptic neurons located in the specific layers is denoted by “P.” The number of functional synaptic connections identified is indicated by “found,” whereas the number of pairs recorded (both connected and unconnected) is indicated by “tested.” The peak uEPSP amplitudes in terms of the layer-specific mean ± SEM, median, and range are quantified in mV. No significant differences were found comparing uEPSP amplitudes. According to a χ2 statistic on contingency table, significant differences (χ2 test p < 0.05) in connectivity were found for L2→L2 versus L2→L4, L2→L2 versus L3→L3, L2→L2 versus L4→L4, L2→L2 versus L5A→L4, L2→L2 versus L5A→L5A, L2→L2 versus L6→L6, L2→L3 versus L3→L3, L2→L3 versus L4→L4, L2→L3 versus L5A→L5A, L2→L4 versus L3→L2, L2→L4 versus L3→L3, L2→L4 versus L3→L5B, L2→L4 versus L4→L2, L2→L4 versus L4→L3, L2→L4 versus L4→L4, L2→L4 versus L4→L5A, L2→L4 versus L5A→L5A, L2→L5A versus L4→L4, L2→L5A versus L5A→L4, L2→L5B versus L5A→L4, L2→L6 versus L4→L4, L3→L2 versus L5A→L4, L3→L2 versus L6→L5A, L3→L2 versus L6→L6, L3→L3 versus L3→L4, L3→L3 versus L5A→L2, L3→L3 versus L5A→L4, L3→L3 versus L5A→L6, L3→L3 versus L5B→L2, L3→L3 versus L5B→L3, L3→L3 versus L5B→L4, L3→L3 versus L5B→L5A, L3→L3 versus L5B→L5B, L3→L3 versus L6→L4, L3→L3 versus L6→L5A, L3→L3 versus L6→L5B, L3→L3 versus L6→L6, L3→L4 versus L4→L3, L3→L4 versus L4→L4, L3→L4 versus L5A→L5A, L3→L5A versus L4→L4, L3→L5B versus L5A→L4, L3→L5B versus L6→L5A, L3→L5B versus L6→L6, L3→L6 versus L4→L4, L4→L2 versus L5A→L4, L4→L2 versus L6→L5A, L4→L2 versus L6→L6, L4→L3 versus L5A→L4, L4→L3 versus L5B→L3, L4→L3 versus L5B→L4, L4→L3 versus L5B→L5A, L4→L3 versus L6→L5A, L4→L3 versus L6→L6, L4→L4 versus L4→L5A, L4→L4 versus L4→L5B, L4→L4 versus L4→L6, L4→L4 versus L5A→L2, L4→L4 versus L5A→L3, L4→L4 versus L5A→L4, L4→L4 versus L5A→L5B, L4→L4 versus L5A→L6, L4→L4 versus L5B→L2, L4→L4 versus L5B→L3, L4→L4 versus L5B→L4, L4→L4 versus L5B→L5A, L4→L4 versus L5B→L5B, L4→L4 versus L6→L2, L4→L4 versus L6→L3, L4→L4 versus L6→L4, L4→L4 versus L6→L5A, L4→L4 versus L6→L5B, L4→L4 versus L6→L6, L4→L5A versus L5A→L4, L4→L5A versus L6→L5A, L4→L5A versus L6→L6, L4→L5B versus L5A→L4, L5A→L2 versus L5A→L5A, L5A→L3 versus L5A→L5A, L5A→L4 versus L5A→L5A, L5A→L4 versus L5A→L5B, L5A→L4 versus L5B→L5B, L5A→L5A versus L5A→L6, L5A→L5A versus L5B→L2, L5A→L5A versus L5B→L3, L5A→L5A versus L5B→L4, L5A→L5A versus L5B→L5A, L5A→L5A versus L5B→L5B, L5A→L5A versus L6→L4, L5A→L5A versus L6→L5A, L5A→L5A versus L6→L5B, and L5A→L5A versus L6→L6.
