In fact, each mossy cell innervates both the ipsilateral and contralateral dentate gyrus. Mossy fibers in the hippocampus project from the dentate gyrus to CA3. The granule cells are tightly packed in the granular cell layer of the dentate gyrus. Pattern separation begins in the dentate gyrus. The CA3 is a portion of the hippocampal formation adjacent to the dentate gyrus. The principal cell type of the dentate gyrus is the granule cell. This process of neurogenesis is confined to the dentate gyrus. Abnormalities are seen in the basal ganglia and dentate nucleus. The laminas are pinnately veined and can be serrate, dentate or entire at the margin. These neurons are responsible for communication between the dentate nucleus and the cerebellar cortex. Sometimes the hippocampus is said to include the dentate gyrus and the subiculum. There are a variety of other differences in the rat, monkey and human dentate gyrus. Calcifications in the caudate, dentate nuclei, putamen and thalami are also common. In a cross-section of the hippocampus, including the dentate gyrus, several layers will be shown. Most species have leaf margins that are entire, but sometimes they are dentate or serrate.