No description available.

The number of species varies greatly among taxa. In birds, for example, the parvorder Passerida contains 3556 species while the Odontophorida (New World Quails) contains only six species. This uneven distribution of species among avian taxa is not random and therefore warrants an explanation. The behavioral drive hypothesis stipulates that the capacity for innovation, coupled with the rapid transmission of the behavioral novelty to conspecifics, may expose individuals to new selective pressures and help fix mutations that would otherwise not be expressed. This should lead to accelerated rates of evolution. I test this hypothesis by examining the link between behavioral flexibility and the number of species per taxon. I adopt a comparative approach and seek a general explanation of richness, thereby removing the traditional focus placed on the success of the songbirds and on their complex singing apparatus. I use two measures of flexibility, feeding innovation rate and relative brain size. (Abstract shortened by UMI.)

Thesis (Ph. D.)--University of Nevada, Reno, 2008. / "May, 2008." Includes bibliographical references. Online version available on the World Wide Web.

Honors Project--Smith College, Northampton, Mass., 2009. / Includes bibliographical references (p. 125)

Many basal forebrain and mesopontine tegmental cholinergic projection systems tend to overlap in their origins. This raises the possibility that these projection systems are collateralized to innervate divergent areas. In experiment one, the degree to which basal forebrain and mesopontine tegmental neurons that innervate the reticular thalamic nucleus have axons that collateralize to innervate the cortex as well was examined with a retrograde fluorescence labeling method combined with immunohistochemistry. A significant portion of the labeled neurons in the region of the nucleus basalis magnocellularis and pedunculopontine tegmental nucleus projecting to the reticular thalamic nucleus were observed to be also labeled (double-labeled) following intracortical tracer injections. Many of these double-labeled neurons displayed choline acetyltransferase choline acetyltransferase immunoreactivity. It was also shown that numerous basal forebrain neurons that innervated the reticular thalamic nucleus contained the calcium-binding protein, parvalbumin. These neurons tended to be located more rostrally than the ChAT immunoreactive neurons; primarily in the region of the ventral pallidum. There was some indication that parvalbumin-containing neurons in the basal forebrain that innervate the reticular thalamic nucleus also have axons that branch to innervate the cortex. Finally, none of the basal forebrain neurons innervating the reticular thalamic nucleus was found to contain somatostatin. In experiment two, the degree to which basal forebrain neurons have axons that collateralize to innervate the interpeduncular nucleus and hippocampus was examined with retrograde fluorescence labeling methods. Labeled neurons projecting to both of these limbic structures were observed only occasionally. Comparison of the distribution of single labeled neurons innervating each of these structures revealed that within the region of origin, in the horizontal limb of the diagonal band, neurons innervating the interpeduncular nucleus tended to be located dorsally to those innervating the hippocampus. The results of these experiments are discussed in relation to their anatomical and functional implications toward a greater understanding of the basal forebrain and mesopontine cholinergic and non-cholinergic projection systems. / Medicine, Faculty of / Graduate

No description available.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 63-82).

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 6 uppsatser.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [90]-110).

Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.