No description available.

In this study, the elasmobranch olfactory system was examined in the periphery, primary centers, and secondary centers. The object of the study was to look for signs of topographical arrangements or spatial segregation in the olfactory system. / Carbocyanine dye (DiI) tracing and Cytochrome oxidase staining reveal that the olfactory epithelium presents signs of functional and morphological heterogeneity. However, no orderly spatial arrangement of olfactory receptor neurons was visible using these techniques. / In vitro anterograde tracing of the primary olfactory projections with biocytin or DiI shows that the olfactory bulb is morphologically and functionally compartmentalized into subunits that receive straight and topographically arranged projections from the epithelium. Mitral cells, as revealed by the rapid Golgi method or retrogradely stained with DiI, belong to two morphologically distinct populations, but are homogeneously distributed across the olfactory bulb subunits. Immunohistochemical examination of the olfactory subunits reveals terminal nerve influence via LHRH fibers, homogeneously distributed in the granule layer of all olfactory subunits. No detectable influence of the trigeminal system is visible in a substance P immunohistochemical search. Finally, transmission electron microscopy reveals that the ultrastructure of the olfactory bulb circuitry is different from that of amniotes. The main difference is that mitral cells lack basal dendrites and therefore have to communicate with each other more directly via reciprocal synapes with granule cells. / Retrograde tracing of the secondary olfactory projections with DiI also shows that the secondary input onto the telencephalon is far more restricted than in the mammalian olfactory system, and that it is segregated into two main components. However, the method used does not allow for more precision in terms of topographical arrangement. / The present study concludes that, although there are signs of ordered projections in the olfactory system of elasmobranch fishes, the use of neural space for analyzing olfactory input is not likely to be significant in the encoding of the olfactory information. / Source: Dissertation Abstracts International, Volume: 54-12, Section: B, page: 6073. / Major Professor: P. P. C. Graziadei. / Thesis (Ph.D.)--The Florida State University, 1993.

Source: Dissertation Abstracts International, Volume: 35-02, Section: B, page: 0663. / Thesis (Ph.D.)--The Florida State University, 1974.

No description available.

No description available.

Thesis (Ph.D.)--Indiana University, Dept. of Psychological Brain Sciences and Cognitive Science, 2009. / Title from PDF t.p. (viewed on Feb. 4, 2010). Source: Dissertation Abstracts International, Volume: 70-04, Section: B, page: 2097. Adviser: Olaf Sporns.

<p> Recent studies have used ecomorphological methods to look at morphological variation in artiodactyl postcranial elements as indicators of paleoenvironment conditions. From these studies, a continuum of variations in the lower limb bones of members of Bovidae and Cervidae in association with habitat conditions have been developed. The focus of this study is to look at variation in a single species, white-tailed deer (<i>Odocoileus virginianus</i>), that occupies a wide range of habitats and determine if regional adaptations exist in populations of different habitat conditions. </p><p> This studies uses linear measurements to assess size and shape variations in the metacarpal, metatarsal, astragalus, and calcaneus between white-tailed deer populations associated with open- and closed-habitat conditions thought-out the Holocene and in modern populations. The Holocene was subdividing into three time units (10,000-5,000, 5,000-3,000, and 3,000-1,000 yr BP) based on environmental shifts and availability of samples. Variations in size and shape were assessed for 1) in open- and closed-habitat conditions in both Holocene and modern deer overall, 2) in habitat conditions in open-classified Holocene deer through time, 3) in modern deer populations along a latitudinal transect,4) between Holocene and modern deer overall, and5) in Holocene and modern for open-classified and closed-classified deer. </p><p> Results indicated that size differences existed between open- and closed-classified deer in both Holocene and modern populations and that deer associated with open-habitat were larger. Shape differences between open- and closed-classified deer in the Holocene appear to be adapted to the environment, however, modern deer offered only limited insight and lacked consistence in variations. Results for variation thought time in Holocene deer indicated that size increased from Early to late Holocene in both the astragalus and calcaneus. Results for shape offered limited and mixed results. Results for variation in population along a latitudinal transect indicated that deer size increase from lower to higher latitudes. Results for shape differences between populations offered limited insight into variation. However, results for the calcaneal tuber functional region did indicated that deer become more open-adapted in relation to the southern population from lower to higher latitudes,. For the comparison of Holocene and modern deer size overall, only the astragalus indicated a clear variation between the two. The astragalus indicated that Holocene deer were larger than modern deer. Results for variation in shape between the two indicated little difference between the two except for the calcaneus, which indicated that modern deer were more open-adapted. Results for size differences in Holocene and modern for open-classified and closed-classified deer offered limited and mixed results. Results for shape differences were also limited; however, the calcaneus strongly indicated that modern closed-classified deer are more open-adapted than Holocene closed-classified deer.</p>

Cardiac activity of Drosophila melanogaster and Manduca sexta changes during metamorphosis. The larval heart has only anterograde contractions. Adult heart activity becomes a cyclic alternation of anterograde and retrograde contractions originated by putative anterograde and retrograde pacemakers. During development, the larval skeletal muscle motoneuron-1 in abdominal segments 7 and 8 becomes respecified to innervate the terminal cardiac chamber of adult Manduca and undergoes morphological and physiological reorganization. MNs-1 activate and sustain the anterograde pacemaker activity of the terminal chamber. The innervation of the adult abdominal heart of Drosophila melanogaster was studied to determine whether the adult heart receives neuronal input or whether its complex activity must be considered independent from the nervous system. The larval heart lacks innervation suggesting a myogenic cardiac impulse. At metamorphosis, neural processes grow onto the myocardium. A pair of glutamatergic transverse nerves innervates bilaterally each cardiac chamber. In addition, CCAP-immunoreactive fibers originating from peripheral, bipolar neurons (BpNs) fasciculate with the transverse nerve projections and terminate segmentally throughout the abdominal heart. To determine the role of this innervation in cardiac function, a novel optical technique based on the movement of GFP-labeled nerve terminals was developed to monitor heartbeat in intact preparations. Simultaneous monitoring of adjacent cardiac chambers revealed the direction of contractions and allowed correlation with volume changes. Intracellular recordings from the first abdominal cardiac chamber, the conical chamber, revealed pacemaker action potentials and the excitatory effect of local glutamate application. Bath-applied glutamate initiated retrograde contractions in semi-intact preparations. Similarly, electrical stimulation of the transverse nerve that serves the conical chamber caused a chronotropic effect and initiation of retrograde contractions. This effect is distinct from that of peripheral CCAP-immunoreactive neurons, which potentiate the anterograde beat. Cardiac reversal was evoked pharmacologically by sequentially applying CCAP and glutamate to the heart. The role of the neuropeptide, Crustacean Cardioactive Peptide (CCAP) in adult Drosophila melanogaster cardiac function was studied by RNA interference (RNAi) and targeted cell ablation. CCAP has a cardioacceleratory effect when it is applied in vitro. Lack of CCAP-innervation in CCAP knock-out flies altered one cardiac phase, the anterograde beat, without preventing the cyclic cardiac reversal.

Skeletal asymmetry is assessed by gross osteometry, combined cortical thickness, joint surface area and osteoarthritis score and compared to the reported handedness for 39 individuals. Based on the principles of bone remodeling there is a tacit assumption in the field of anthropology that handedness is the sole source of skeletal asymmetry and thus is predictable from the asymmetric pattern. In general, bone does hypertrophy in response to increased loading and atrophies when loads are chronically diminished. This study demonstrates that handedness is an ambiguous cultural construct and is nor the only contributor to skeletal asymmetry. Individuals exhibit a mosaic of asymmetry between the right and left sides for different measures. The features ranged from zero to 48.0% for the expression of asymmetry in a direction contrary to that expected by the principles of bone remodeling and the reported hand preference. The greatest percent of misclassification occurs for non-right-handed individuals and females. There is a greater frequency of misclassification for measures that reflect function (cortical thickness, joint surface area and osteoarthritis) compared to those that are subject to functional influences only during the growth and development of the individual (gross osteometry). These results indicate that the non-dominant limb is subject to activities heavy enough to stimulate bone remodeling but not dynamic enough to be classified as 'handedness'. Based on this sample skeletal asymmetry is not a reliable, definitive marker for hand preference.

Breast milk contains many biologically active substances, including epidermal growth factor (EGF), that are absent from artificial milk formulas. Previous studies have shown dramatic growth and maturation effects of milk-borne EGF on the intestine. This raises the question as to whether artificial milk formulas should be supplemented with biologically active substances, such as EGF. As a result, this dissertation examined whether feeding suckling rats artificial milk formula supplemented with EGF modulates liver development. The normal development of hepatic cells in suckling and weanling rats also was characterized. Additionally, this dissertation examined whether gut-derived endotoxin and tumor necrosis factor alpha (TNFα) play a role in liver development. Dam-fed suckling and weanlings showed increases in the reorganization of hepatocellular plates, numbers of binucleated hepatocytes, and a tendency for sinusoidal endothelial cell fenestrae density and porosity to increase with age. Monocytic derived cells increased at days 8-12 and decreased at day 16. Hepatic stellate cells decreased with age. Colon microbial flora and portal venous endotoxin were present from day 8 onward. Compared to artificial milk formula feeding alone, EGF in the artificial formula elicited increased numbers of binucleated hepatocytes, changes in colon microbial flora, and a tendency for increased numbers of Kupffer cells and portal venous endotoxin. Compared to breast milk, the artificial diet caused decreases in binucleated hepatocytes, increases in monocytic derived cells, Kupffer cells, hepatic stellate cells, portal venous endotoxin and changes in the composition of the colon microbial flora. These increases in cells may be due to colonization of the colon with microbial flora which increased portal venous endotoxin. Increased endotoxin may provide a stimulus for the recruitment of monocytic derived cells to the liver and differentiation into Kupffer cells, which then stimulates hepatic stellate cell proliferation. However, the increases in portal venous endotoxin were not sufficient to elicit hepatic TNFα, mRNA production. In conclusion, milk-borne EGF is involved in differentiation of hepatocytes and changes colon microbial flora that occur in suckling rats. Whether accelerating maturation of hepatocyte is beneficial or detrimental to the suckling rats remains to be determined. Therefore, the supplementation of artificial milk formula with EGF warrants further consideration and research.