Morphometric changes between one-day-old and adult chicken neurons of the nucleus isthmi

The most important parameters of the neuronal soma of neurons of the chicken nucleus isthmi have been analyzed, with photo and morphometric techniques, in order to quantify the morphological variations present during the first months of the life to determine if the developmental changes of both neuronal populations of the nucleus are similar or different. The study was carried out on neurons of the parvicellular part and magnocellular part of the Nucleus Isthmi in one day and four month-old chickens. The soma shape did not change during this time interval in parvicellular neurons. The magnocellular neurons became more fusiform. In-one-day old chickens, the section shapes of the neuronal soma and optical density, are similar in both the magnocellular and parvicellular parts of the nucleus. The area and the maximum and minimum diameters do not present significant differences between magnocellular and parvicellular neurons. In adults, the maximum diameter, neuronal area and optical density are higher in magnocellular neurons than in parvicellular neurons. In summary, magnocellular neurons of the nucleus Isthmi of adults are bigger, darker and more elongated than the ones that constitute the parvicellular territory.