Figure 1.
New Neurons in the Adult Neocortex. (A) 4–5 week old neuron in the adult rat anterior neocortex labeled with BrdU (green) and the neuronal marker NeuN (red). The right panel shows colocalization of BrdU and NeuN in several confocal planes. (B) 4-week-old neuron in the adult mouse motor cortex after selective killing of mature motor neurons. (C) 4–5 week old neuron in the adult rat anterior neocortex labeled with BrdU (green) and the neuronal marker neuron-specific enolase (red). (D) 2-week-old neuron in the macaque prefrontal cortex labeled with BrdU (red) and NeuN (green). (E) A neuron in the macaque prefrontal cortex labeled with BrdU (red) and retrogradely labeled with Fluoro-Emerald (green), demonstrating the presence of an axon. (F) Electron micrographs of a 4-week-old 3H-thymidine-labeled neuron in the rat visual cortex. Top inset shows the autoradiographic silver grains over the nucleus; bottom inset shows a synapse onto the cell body at higher magnification; right panel shows the beginning of the axon (arrowheads) at higher magnification. (G, H) New neurons in the rat anterior cortex staining for BrdU (green) and GABA (G) or the GABA synthesizing enzyme GAD-67 (H), indicating that these are GABAergic interneurons. Scale bar, 5 μm (D), 10 μm (A, B, C, G, H), 20 μm (E). Photographs reprinted from Dayer et al., 2005 (A, C, G, H), Chen et al., 2004 (B), Gould et al., 2001 (D), Gould et al., 1999 (E), Kaplan, 1981 (F).