Navegando por Assunto "Neuroanatomia"

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Acesso aberto (Open Access)
Alterações da formação hipocampal do Calidris pusilla associadas à migração outonal de longa distância
(Universidade Federal do Pará, 2017-08-31) MAGALHÃES, Nara Gyzely de Morais; DINIZ, Cristovam Guerreiro; http://lattes.cnpq.br/1025250990755299; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
After breeding in the upper Arctic tundra, shorebirds affected by migratory restlessness trace an inherited preliminary route and use compasses, maps and visual landmarks, until they reach, in the northern hemisphere, stopover sites that have the necessary nutritional resources for fast and high gain of energy reserves for migratory journey, as in the Bay of Fundy-Canada. Following this stopover site that is used by 75% of the population of Calidris pusilla, the long-distance autumn migratory experience continues with uninterrupted 6-day non-stop flights over the Atlantic until these birds reach South America and then the island of Canela-Brazil. To test the hypothesis that the long-distance migratory process would influence neurogenesis, astrogenesis and activation of earlier-expression genes, we captured 12 individuals in full migratory activity in the Bay of Fundy and 9 individuals in the Island of Canela in Brazil. After selective immunostaining for mature neurons (NeuN), immature neurons (Dcx), astrocytes (GFAP), and neuronal activation by early genes (c-Fos), we quantified these markers in the hippocampal formation and compared the results of this quantification of the individuals in migration (Bay of Fundy) with those of wintering birds (Canela Island). We used quantitative stereological analyzes to estimate the total number of cells of hippocampal formation, number of active cells, total number of astrocytes and young and mature neurons. To verify if the differences found were statistically significant, we used the Student t test. Our results confirmed that autumnal migration alone, caused hippocampal changes in Calidris pusilla. After migration, we detected that the hippocampal formation has fewer activated cells and fewer astrocytes, more new neurons and greater relative volume in the quantified hemisphere (left hemisphere). However, this process did not influence the number of total cells and mature neurons. We suggest that the difference found between the volume and number of new neurons, of the full migration and wintering individuals, possibly occurred due to the migratory process in combination with local conditions found during the beginning of the wintering period. Taken together our findings demonstrate long-distance migratory shorebirds offer a unique opportunity to investigate many issues related to the cellular neurobiology of migration in general, and, on the neural plasticity associated with hippocampal neuronal and neurogenesis in adult birds.
Acesso aberto (Open Access)
Identificação neuroanatômica dos núcleos cerebrais relacionados ao canto em Uraeginthus cyanocephalus (ordem Passeriformes, subordem Oscines, família Estrildidae)
(Universidade Federal do Pará, 2011-09-28) LOBATO, Muriele Nazareth; LIMA, Silene Maria Araújo de; http://lattes.cnpq.br/8961057812067156
Song control regions in passerine birds are sexually dimorphic in the adult brain of species like the zebra finches in which males sing whereas females do not. In the majority of tropical bird species, however, females sing as well. The issue of female song production began to attract more attention recently, but the neural mechanisms involved in the female song production are still poorly understood. Here we study for the first time the ontogeny of the song control system in a species, in which both male and female sing regularly. In blue-capped cordon blues (Uraeginthus cyanocephalus), a close relative of the zebra finch, females sing but have shorter songs with fewer syllables compared to the males. Volumetric changes of forebrain song control regions (the HVC, the RA and the LMAN) of the blue capped cordon bleu have been quantified in both sexes at 20, 30, 50 and ≥100 days posthatching, by using the Nissl- taining method and in situs hybridization. In both sexes, no significant differences in the volumetric development of HVC (proper name) were detected. The Nissl-efined volume of the HVC in males was always superior to the females values, including the adulthood, when the volume values became significant bigger in males than in females. In contrast, the volume of the robust nucleus of the archistriatum (RA) increased with age reaching the highest values in adulthood. The Nissl-defined RA volume incresed by 2,21 times in males (from 0,104 mm3 at 20 days to 0,236 mm3 in adulthood). In females, no significant differences in the volumetric development of RA were detected.