Tucked into the lower, rear portion of the brain, the cerebellum plays key roles in motor learning, motor memory and sensory perception. It's also where the majority of metastatic childhood brain tumors are located. Yet scientists still know very little about its early growth.
Now, new research has pinned down how cells in the cerebellum migrate and differentiate during the first stages of brain development, and shows that different combinations of regulatory proteins called transcription factors are responsible for driving these changes.
Transcription factors are proteins that can turn genes on or off, or even just fine-tune a gene's activity. According to the new research, published in the Journal of Neuroscience by Mary E. Hatten, Frederick P. Rose Professor and head of Rockefeller University's Laboratory of Developmental Neurobiology, and Daniver Morales, a postdoctoral fellow in the lab, precise patterns of activity of transcription factors in the brain are responsible for defining the three major types of neurons in the cerebellum. And these specific transcription factor patterns, combined with the young neurons' migration pathways, appear to generate the cerebellum's two fundamental structures: the cerebellar nuclei and the cerebellar cortex.
Using newly developed transcription-factor pattern markers, in conjunction with fluorescent microscopy, Hatten and Morales found that they could visualize the three types of neurons that make up the cerebellum: deep nuclei, located in the very center; Purkinje cells, which are some of largest neurons in the brain; and the tiny, plentiful granule cells, which make up the cerebellar granule layer. From there, the researchers could follow the generation and migration of these cells in the developing brain.