Table 1.

Summary of learning-related changes in CA1 neurons from young and aged rabbits

Group (number of rabbits)Postburst after hyperpolarization (n)Frequency accommodation (n)
Amplitude, mVArea, mV × msecDuration, msecNumber of spikes
Naive, young (4)−5.00  ± 0.1  (0/15)−4937  ± 286  (0/15)3084  ± 142  (0/15)7.2  ± 0.3  (1/15)
Naive, aged (6)−6.34  ± 0.1  (0/13) 1-a −7554  ± 362  (0/13) 1-a 3854  ± 148  (1/13) 1-a 5.2  ± 0.2  (0/13) 1-a
Slow learners, young (4)−5.21  ± 0.3  (0/11)−5838  ± 549  (0/11)3269  ± 220  (0/11)6.5  ± 0.6  (0/11)
Slow learners, aged (5)−6.11  ± 0.4  (1/11)−8362  ± 1554  (0/11)3764  ± 247  (0/11)5.6  ± 0.5  (2/11)
Trace 60%, young (6)−3.02  ± 0.2  (6/15)1-153−2285  ± 452  (2/15)1-1532238  ± 307  (2/15)*10.2  ± 0.8  (4/15)
Trace 60%, aged (7)−3.01  ± 0.2  (17/19)1-153−2822  ± 426  (10/19)1-1532861  ± 290  (2/19)*9.2  ± 0.7  (13/19)
Trace 80%, young (3)−2.50  ± 0.3  (4/9)1-153−1934  ± 630  (4/9)1-1532143  ± 412  (1/9)*11.7  ± 1.6  (4/9)1-153
Trace 80%, aged (1)−3.06  ± 0.5  (3/4)1-153−2595  ± 858  (2/4)1-1532378  ± 277  (1/4)*10.5  ± 1.9  (3/4)1-153
  • F1-a Neurons from aged experimentally naive rabbits were significantly different from those of young naive rabbits (AHP amplitude, p < 0.005; AHP area, p < 0.01; AHP duration, p < 0.05; number of spikes, p < 0.01).

  • Significantly different from neurons of both age-matched control groups (naive and slow learners):

  • * p < 0.05,

  • p < 0.01,

  • F1-153 p < 0.001. Numbers in parentheses (n) indicate the ratio of individual cells with reduced AHPs or accommodation to the number of cells studied in that group.