The central nervous system, or CNS, as it is also known as, is that part of the nervous system, which is responsible for coordinating the activity of all the parts of the bodies of the multicellular organisms. In case of vertebrates, the central nervous system is located in the meninges. It constitutes the bulk of the nervous system; and consists of the brain as well, along with the spinal cord. In association with the peripheral nervous system it plays a very important role in the control of behavior.

The central nervous system is located within the dorsal cavity. The brain is located in the cranial cavity, while the spinal cord is located in the spinal cavity. Now, the brain is protected by the skull, whereas the spinal cord is protected by the vertebrae.

As it is, the telencephalon makes way for the striatum, the hippocampus, as well as the neocortex, while its cavity becomes the lateral ventricles. The diencephalon develops the thalamus, hypothalamus, the subthalamus, as well as the epithalamus, with its cavity along the third ventricle. The mesencephalon develops the cerebral peduncle, the tectum, as well as the pretectum and its cavity grows into the cerebral aqueduct, or the mesencephalic duct. Similarly, the rhombencephalon makes way for the pons, the cerebellum, as well as the medulla oblongata, as its cavity becomes the fourth ventricle.

As a matter of fact, the central nervous system is believed to be a system responsible for information processing, wherein a suitable motor output is calculated as a response to a sensory impulse. Yet, several studies and researches reveal that motor activity is present much before the maturation of the sensory systems. It also reveals that the senses only influence behavior without dictating it.

The primary pattern of the central nervous system is very much conserved throughout the various species of vertebrates, during evolution. A major development that can be observed is in regard to a progressive telencephalisation, whereas in case of the reptilian brain, that particular region is only an addendum to the large olfactory bulb, it represents majority of the volume of the mammalian central nervous system. In case of the human brain, the telencephalon involves majority of the diencephalon, as well as the mesencephalon. As it is, the allometric study of the brain size of different species reveal a striking continuity from rats to whales, helping in completing the knowledge in regard to the evolution of the central nervous system obtained through cranial endocasts.

Tags: central nervous system, multicellular organisms, spinal cord