Dissection and Damage
According to One Life, much of our early study of the brain came from careful examination of the structure of the brain of diseased patients. Early brain studies looked at the gross anatomy of the brain and then cut into the brain (a process known as dissection) to examine the interior of the brain. In some cases, thin slices of tissue were examined under a microscope to gain an idea of what the human brain looked like on a cellular level. These studies were done along with studies that measured the effects of brain damage. Scientists observed the changes in patients' behavior and brain function when they had injuries to the brain. By correlating the patients' symptoms (such as problems with speech or muscle control) to the region of the brain where the damage occurred, a better understanding of the function of different brain regions was reached.
Electrical Activity
Because active nerve cells generate small electrical currents, we can also gain an understanding of how the brain works by examining these electrical changes. The Martinos Center (which is part of the Harvard Medical School) notes that we can measure these electrical changes in two different ways. Electroencephalography (EEG) uses small electrodes that can measure the electrical activity in different parts of the brain. Because electric currents also cause magnetic fields, magnetoencephalography can also measure brain activity. These techniques allow for the study of live human brains. They allow researchers to measure the activity of specific parts of the brain while the patient is involved in certain tasks, such as thinking, experiencing emotions and controlling the movement of the body's muscles.
Functional MRI
Functional magnetic resonance imaging (functional MRI or fMRI) is another way that researchers can study the human brain. The Columbia University Medical Center's Program for Imaging and Cognitive Sciences explains that fMRI looks at brain activity by taking advantage of the fact that areas of the brain that are more active need more blood. This increased blood flow causes the buildup of a protein called deoxyhemoglobin, which can then be detected using an MRI machine. The Medical Center notes that this technology has identified parts of the brain involved in processing visual signals, speech and language, as well as muscle movement.
