Neuroscience is the study of the nervous system and its components. Neuroscientists may examine the nervous systems of humans and higher animals as well as simple multicellular nervous systems, or investigate nervous phenomenon at the cellular, organelle, or molecular level.
Neuroscience principally originated with three European scientists working at the end of the nineteenth and the beginning of the twentieth century. Camillo Golgi, an Italian physician, perfected a vital laboratory technique that first allowed scientists to trace the workings of the nervous system. Golgi completed a medical degree at the University of Padua in 1865, and then became a medical researcher at the University of Pavia. He was interested in cells and tissues, and experimented with ways to stain cells so they could be seen. Researchers before him had prepared cells with organic dyes, but Golgi found that staining with silver salts gave much clearer results. He became fascinated with nerve tissue, and using his staining process, he was the first to see in fine detail how this tissue was organized. He proved that the fibers of nerve cells did not meet completely, but left a gap, now known as a synapse. He devoted his life to mapping the structure of the nervous system. Golgi's work was furthered by a Spanish medical researcher, Santiago Ramón y Cajal. Ramón y Cajal, working at the University of Zaragoza, first improved on Golgi's staining method, then used it to discover the connection between the gray matter in the brain and the spinal cord. He shared the Nobel Prize in medicine with Golgi in 1906.
Golgi and Ramón y Cajal established the anatomy of the nervous system. The English neurologist Charles Scott Sherrington is credited with founding modern neuroscience with his work on the functioning of the nervous system. In other words, he brought the science from describing what the nervous system was to showing how it worked. His research explored the brain's ability to sense position and equilibrium, and the reflex actions of muscles.
Many other researchers continued to explore the workings of the nervous system. As laboratory imaging techniques progressed, neuroscientists were able to look at nerve cells at the molecular level. This allowed scientists to map the growth of nerve cells and nerve networks, and to study how individual cells process, store, and recall information.
Working with living brains to explore nerve function was all but impossible until the late 1970s, when sophisticated brain imaging machines were first developed. Positron emission tomography (PET) revolutionized neuroscience by allowing scientists to produce pictures of a working brain. Since then, scientists and engineers have come up with even better brain imaging systems, such as functional magnetic resonance imaging (fMRI). Using fMRI, neuroscientists can detect increases in blood oxygenation during brain function, and this shows which areas of the brain are most active. Brain activity occurs very quickly—neurons can respond to stimulus within 10 milliseconds—and very sophisticated equipment is needed to capture such fleeting movements. So-called neuroimaging is one of the hottest fields in neuroscience, as neurologists and technicians work together to find new ways of recording nerve action. Researchers in the late 1990s explored ways to map the flux of sodium ions within the brain, giving a direct record of neural activity, or to measure the scattering of light by brain tissues with fiber-optics. Both these techniques hope to give a more precise picture of which areas of the brain become active when a person thinks.