Table 1.
The mean density of total neurons and GABA-positive neurons and ratios of GABA-positive neurons to total neurons in various cortical layers (I, II–III, IV, V and VI) in the primary visual cortex of young adult and old rats.
| Subjects | Cortical layer | ||||
|---|---|---|---|---|---|
| I | II–III | IV | V | VI | |
| Total cortical neurons (cells/mm2) | |||||
| Young rats | 3309 ± 817 | 14,668 ± 2948 | 17,882 ± 2928 | 16,261 ± 3413 | 13,098 ± 3551 |
| Old rats | 3282 ± 522 | 14,568 ± 2749 | 17,401 ± 1879 | 15,868 ± 2275 | 12,887 ± 3869 |
| GABA-positive neurons (cells/mm2) | |||||
| Young rats | 2765 ± 839 | 2139 ± 542 | 3034 ± 681 | 2779 ± 495 | 1821 ± 534 |
| Old rats | 954 ± 502 | 771 ± 242 | 881 ± 196 | 1117 ± 426 | 483 ± 151 |
| Proportion of GABA-positive neurons (%) | |||||
| Young rats | 82.6 ± 10.6 | 14.8 ± 3.0 | 16.8 ± 2.1 | 18.1 ± 5.6 | 14.3 ± 3.2 |
| Old rats | 29.1 ± 13.8 | 5.3 ± 1.3 | 5.1 ± 1.3 | 6.9 ± 2.3 | 4.1 ± 1.9 |