A neuron, also known as a neurone, or nerve cell, is an electrically excitable cell that receives, processes, and transmits information through electrical and chemical signals. These signals between neurons occur via specialized connections called synapses. Neurons can connect to each other to form neural networks. Neurons are the primary components of the central nervous system, which includes the brain and spinal cord, and of the peripheral nervous system, which comprises the autonomic nervous system and the somatic nervous system. There are many types of specialized neurons. Neuroscience (or neurobiology) is the scientific study of the nervous system. It is a multi-disciplinary branch of biology, that deals with the anatomy, biochemistry, molecular biology, and physiology of neurons and neural circuits. It also draws upon other fields, with the most obvious being pharmacology, psychology, and medicine.