Figure 4.
Newly formed neurons within the reorganized somatosensory cortex showing a pyramidal neuronal phenotype. a, b, Examples of BrdU/NeuN-colabeled neurons that had a pyramidal phenotype with respect to soma diameter and shape. Inset in a shows orientation and location of cells in layer V in Brodmann area 3b. See supplemental Figure 1 (available at www.jneurosci.org as supplemental material) for images from the z-plane gallery of the colabeled cell shown. c–f, Examples of BrdU/FR-colabeled neurons showing a classic pyramidal soma and dendritic morphology. Somata were 16–25 μm in diameter and approximately twice the size of typical BrdU/CB-colabeled interneurons (see Fig. 3). d, Reconstructions of BrdU/FR-colabeled neurons in c. Pia is to the left of image, and cells were located in deep layer 3 in area 3b. The red cell shown at the far left in c and d was FR positive but BrdU negative, and is an example of a mature neighboring pyramidal neuron. The absence of FR in the center of this cell is not atypical of an FR-labeled pyramidal neuron (for examples, see Bareyre et al., 2004; Schofield, 2008). Note that NeuN labeling appears faint in the image in c relative to the much brighter FR labeling. This reflects bright FR labeling and not faint NeuN labeling, and is a photographic artifact. Note that while both FR and NeuN were visualized at the same wavelength, the brighter FR labeling masked the fainter NeuN label, so only BrdU/FR, and not BrdU/FR/NeuN, could be positively identified in the cells shown. NeuN does not label dendrites, which makes the identification of FR definitive. e, Orthogonal view of colabeled cells in c and d. f, Spectral intensity overlays [for excitation wavelengths 488 nm (green) and 594 nm (red)] for two of the BrdU/FR-colabeled cells in c and d. Scale bars: a–c, 20 μm.