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

SeriesAgeTotal width of apical arbor (micrometers)Series location (micrometers from cell body layer)Volume analyzed (cubic micrometers)Total number of synapsesNumber of filopodia synapsesNumber of shaft synapsesNumber of stubby synapsesNumber of spine synapses
R52aPN1165100 346.22 64 941 5 4
R52bPN11651301066.411162576 6 2
R53PN1160 20 781.38 97244222 1
R55PN1140125 391.04 501322 6 5
R48aPN4200100 482.17 801846 5 3
R48bPN4200100 332.81 51 831 5 2
R60aPN4250115 638.12 90114515 7
R60bPN4250115 573.78109275816 2
R43aPN6300265 270.921203354 817
R43bPN6300265 200.961031058 517
R44aPN6275 40 553.8711817531417
R44bPN6275115 610.4811427312527
R45aPN12300266 77.0610712251645
R45bPN12300266 122.27 9910181248
R47bPN12400180 85.33105 3471833
R47cPN12400180 60.54 60 2232012
  • 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.