Table 1.
Location, volume, and number of synapses for each set of serial section electron micrographs. R numbers are individual rat numbers for a total of nine rats; letters a, b, and c are the specific series identifiers
| Series | Age | Total width of apical arbor (micrometers) | Series location (micrometers from cell body layer) | Volume analyzed (cubic micrometers) | Total number of synapses | Number of filopodia synapses | Number of shaft synapses | Number of stubby synapses | Number of spine synapses |
|---|---|---|---|---|---|---|---|---|---|
| R52a | PN1 | 165 | 100 | 346.22 | 64 | 9 | 41 | 5 | 4 |
| R52b | PN1 | 165 | 130 | 1066.41 | 116 | 25 | 76 | 6 | 2 |
| R53 | PN1 | 160 | 20 | 781.38 | 97 | 24 | 42 | 22 | 1 |
| R55 | PN1 | 140 | 125 | 391.04 | 50 | 13 | 22 | 6 | 5 |
| R48a | PN4 | 200 | 100 | 482.17 | 80 | 18 | 46 | 5 | 3 |
| R48b | PN4 | 200 | 100 | 332.81 | 51 | 8 | 31 | 5 | 2 |
| R60a | PN4 | 250 | 115 | 638.12 | 90 | 11 | 45 | 15 | 7 |
| R60b | PN4 | 250 | 115 | 573.78 | 109 | 27 | 58 | 16 | 2 |
| R43a | PN6 | 300 | 265 | 270.92 | 120 | 33 | 54 | 8 | 17 |
| R43b | PN6 | 300 | 265 | 200.96 | 103 | 10 | 58 | 5 | 17 |
| R44a | PN6 | 275 | 40 | 553.87 | 118 | 17 | 53 | 14 | 17 |
| R44b | PN6 | 275 | 115 | 610.48 | 114 | 27 | 31 | 25 | 27 |
| R45a | PN12 | 300 | 266 | 77.06 | 107 | 12 | 25 | 16 | 45 |
| R45b | PN12 | 300 | 266 | 122.27 | 99 | 10 | 18 | 12 | 48 |
| R47b | PN12 | 400 | 180 | 85.33 | 105 | 3 | 47 | 18 | 33 |
| R47c | PN12 | 400 | 180 | 60.54 | 60 | 2 | 23 | 20 | 12 |
The total number of synapses includes synapses that could not be identified through serial sections. Only complete, identifiable synapses were used for analysis, yielding a total of 1417 for all ages.