Most of our knowledge about the different regions of the brain and their functions has come from studying patients with brain damage. Some scientists use animal brains for research because it is unethical to take out the brains of living humans.
However, human brains are more complex than animal brains, so the research is often unreliable. This also means that we have a limited understanding of the brain, so it is often very difficult to treat brain disease.
Two ways that neuroscientists have been able to investigate the functions of different areas in the brain are:
Images of the brain are taken while a patient performs various tasks to see which parts of the brain are active during the task (e.g. reading a book). Some examples of these scans are CT scans, PET scans and Magnetic Resonance Imaging (MRI).
MRI scanners use strong magnetic fields and radio waves to produce detailed images of the brain.
Scientists use a weak electrical current is used to stimulate parts of the brain, and then the patient is asked to describe what they experience (e.g. a taste or smell). For example:
An electroencephalogram (EEG) is a test that detects electrical activity in the brain using electrodes that are attached to the scalp.
An EEG can detect changes in brain activity, so it can be used to evaluate many types of brain disorders.
Patients with brain damage can be studied to observe changes in their personalities or their capabilities.
A popular example is Phineas Gage, who suffered a railroad accent in 1848. This caused a metal rod to pass completely through his skull and damage his left frontal lobe. He miraculously survived, however, doctors observed changes in his personality and behaviour.
Brain damage and brain disease can be difficult to treat because it takes a long time to replace neurones after damage. If a brain disorder is left untreated, it can get much worse, which is likely to reduce the patient’s quality of life. Brain surgery is often one of the few options available, but it carries a lot of risks.