Development of accessory lobes in the spinal cord of the turkey (Meleagris gallopavo)

Accessory lobes are unusual structures of the lumbosacral segment of the avian spinal cord, which are characterized by glycogen accumulation. They consist of neuroglial cells and neurons, which are similar to the multipolar neurons of the ventral horns of the grey matter. Development of the accessory lobes is different from that of other glycogen-rich regions of the avian spinal cord. At the 8(th) day of embryonic development in turkey, neuroblasts are visible at the ventrolateral margins of the spinal cord, and they will differentiate in multipolar neutrons. At the 15(th) day of embryonic development glioblasts appear in accessory lobes. At the 16(th) day, accessory lobes achieve their final form and obtain first PAS-positive granules of glycogen. Glycogen accumulates in neuroglial cells, and the appearance of a lesser amount of glycogen in multipolar neurons is very interesting.