Development of the nervous system in humans in the lower part. Neuronal migration is the method by which neurons travel from their origin or birthplace to their final position in the brain. There most common means of migration are radial and tangential migration. Neuronal precursor cells proliferate in the ventricular zone of the developing neocortex. The first postmitotic cells to migrate from the preplate which are destined to become Cajal-Retzius cells and subplate neurons. These cells do so by somal translocation. Neurons migrating with this mode of locomotion are bipolar and attach the leading edge of the process to the pia. The soma is then transported to
Chemical plant or economic conditions change and re-optimization is desirable. In more modern times, computer simulations or other computer calculations have been used to help in chemical plant design or optimization. In process control, information gathered automatically from various sensors or other devices in the plant is used to control various equipment for running the plant, thereby controlling operation of the plant. Instruments receiving such information signals and sending out control signals to perform this function automatically are process "controllers". Previously, pneumatic controls were sometimes used. Electrical controls are now common. A plant often has a control room with displays of parameters