Sex difference in cellular proliferation within the telencephalic ventricle zone of Bengalese finch

Sexual Differences in Cell Proliferation in the Ventricular Zone, Cell Migration and Differentiation in the HVC of Juvenile Bengalese Finch

“…The stereotaxic point 0.0 was defined both for the anteroposterior and the mediolateral axes as the branch point of the sagittal sinus that lies just anterior to the rostral tip of the cerebellum. The “hot spot” for cell proliferation at the end of dorsal ventricular zone (which is relatively close to the HVC, and is thus most probably a potential site for HVC progenitor cells [13], [19]) was electrically injured at either side of the hemispheres with the coordinate (Lateral: 1.0 mm, Anterior: 3.2 mm, Deep: 1.3 mm) for 90 s at 100 µA, whereas the other side was kept intact, and used as control. After producing the lesion, the animals were returned to the colony in which they were kept with their family until P60, when the HVC was well developed [30].…”

“…The birds were allowed to survive for different times: 2 h (labeled cells do not begin to migrate out of ventricular zone, [19]), 5 d (labeled cells begin to migrate toward their targeting area, [11]) and 10 d or 25 d (labeled cells have reached their targeting area, [10], [12], [17]). As described above, 10-µm sections were cut, and the sections were then covered with a layer of emulsion.…”

“…Only cells with a clear neuronal morphology (darkly stained nucleoli or relatively large cytoplasm) were regarded as neurons. A neuron was considered labeled with [ 3 H]-thymidine if autoradiographic grains overlying its nucleus were over 10× background density (Background grain counts were determined for each specimen) [19]. For double labeling, the sections were first processed for immunohistochemistry, and then [ 3 H]-thymidine autoradiography, as described above.…”

“…We then studied whether there were sexual differences in the cell proliferation in the HVC ventricle site at posthatching 15 days (P15) when HVC progenitor cells are generated in large scale [14], [15], [19], and in the number of cells migrating towards HVC along radial glia fibers, or differentiating toward neurons within HVC. To exclude the effect of gonad-derived steroids in vivo , the corresponding studies were also performed in vitro .…”

Brains, Lifestyles and Cognition: Are There General Trends?

“…Not only is the association between repertoire and nucleus size clearly established at the inter- [DeVoogd et al, 1993] and intra-specific [Garamszegi and Eens, 2004] levels, it also appears to characterize gender differences: species in which only males sing have dimorphic song nuclei, whereas species where both sexes sing do not [Brenowitz, 1997]. In addition, evidence is accumulating that song learning coincides with neuronal growth in HVC [Zeng et al, 2007], that HVC and RA control different levels of song organization [Yu and Margoliash, 1996], that larger learned repertoires are reflected in increased dendritic spine density in HVC [Airey et al, 2000a], that females select for males with both a larger HVC and a larger repertoire [Airey and DeVoogd, 2000], that HVC size and song complexity predict male quality [Pfaff et al, 2007] and that both repertoire size and HVC size are inherited [Airey et al, 2000b]. Eventually, the impressive advances that characterize the song learning literature need to be imitated in other areas of neuroecology.…”