Human brain basal ganglia, and related structures. The diencephalon gives rise to the thalamus and hypothalamus. The hindbrain also splits into two areas – the metencephalon and the myelencephalon. The metencephalon gives rise to the cerebellum and pons. The myelencephalon gives rise to the medulla oblongata. Also during the fifth week, the brain divides into repeating segments called neuromeres. These are known as rhombomeres seen in the hindbrain. A characteristic of the brain is gyrification (wrinkling of the cortex). In the womb, the cortex starts off as smooth but starts to form fissures that begin to mark out the different lobes of
Anatomy of the cerebellum uniform, with connections organized into a rough, three-dimensional array of perpendicular circuit elements. This organizational uniformity makes the nerve circuitry relatively easy to study. To envision this "perpendicular array", one might imagine a tree-lined street with wires running straight through the branches of one tree to the next. There are three layers to the cerebellar cortex; from outer to inner layer, these are the molecular, Purkinje, and granular layers. The function of the cerebellar cortex is essentially to modulate information flowing through the deep nuclei. The microcircuitry of the cerebellum is schematized in Figure 5. Mossy and climbing fibers carry