Furthest extent of fibers after cortical or thalamic injections in hamster embryos
| E11.5 | E12.5 | E13.5 | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Neocortex | GE | Thalamus | Neocortex | GE | Thalamus | Neocortex | GE | Thalamus | |
| Cortical injections | |||||||||
| n | 12 | 6 | 0 | 2 | 13 | 0 | 1 | 11 | 3 |
| % | 67 | 33 | 0 | 13 | 87 | 0 | 7 | 73 | 20 |
| Thalamic injections | |||||||||
| n | 0 | 5 | 3 | 1 | 5 | 0 | 7 | 0 | 0 |
| % | 0 | 62 | 38 | 17 | 83 | 0 | 100 | 0 | 0 |
For each age, the table indicates the number (n) and percentage (%) of embryos in which the distal-most site reached by the fibers was the neocortex, GE, or thalamus. Although corticofugal fibers reach the GE in 1 case out of 3 at E11.5, none are observed in the thalamus 1 d later, and the great majority are terminating instead in the GE. They reach the thalamus only 2 d after they are observed in the GE for the first time. At E11.5 and E12.5, the most advanced thalamocortical fibers are found mainly in the GE, and very few are found in the cortex. At E13.5, projections into the cortex are observed in all experimental cases analyzed.