Neuroscience: The Study of the Nervous System & Its Functions

Neuroscience is the scienti1⁄2c study of the nervous system (the brain, spinal cord, and peripheral nervous system) and its functions. The belief that the brain is the organ that controls behavior has an cient roots, dating to early civilizations that connected loss of function to damage to parts of the brain and spinal cord. But the modern era of neuroscience began–and continues to progress–with the development of tools, techniques, and methods used to measure in ever more detail and complexity the structure and function of the nervous system. The modern era of neuroscience can be traced to the 1890s, when the Spanish pathologist Santiago Ramon y Cajal used a method developed by the Italian physician Camillo Golgi to stain nerve tissues to visualize the morphology and structure of the neurons and their connections. The detailed de scription of the neurons and their connections by Cajal, his students, and their followers led to the “neuron doctrine,” which proposed that the neuron is the functional unit of the nervous system. We now know that the human brain contains ap proximately one hundred billion neurons and that these neurons have some one hundred trillion connections, forming functional and de1⁄2nable circuits. These neural circuits can be organized into larger