There are several methods for studying the human brain. Some methods are observational, while others are invasive. Some would argue that the invasive methods are unethical and this research should only involve animals other than humans, however, there are occasions where invasive methods of investigating the human brain become necessary.
When stereotaxic surgery is being performed, a two dimensional atlas is used to access the specific area requiring treatment. The patient's head is firmly held in position necessary for surgery, and a device called an electrode holder is positioned to make the incision in the appropriate place. The electrode holder is maneuvered by mechanical means (Pinel, 2007, p83).
Because it is also an invasive process, lesion methods of brain study are only ever used on human patients as a necessary method of treatment. There are three types of lesions, one being the aspiration method where targeted tissues are drawn out of the brain, using a suction system. The electrolytic lesion is different because it used electric current to destroy a particular section of the brain. A small device with a cutting tool can also be used to remove diseased areas of the brain; this procedure is known simply as the knife cut method (Pinel, 2007, p 85).
The Stimulation method is another process used for researching brain function, although is not used on humans unless necessary for medical treatment. The stimulation method involves sending electrical current through brain tissue to determine the effects of behavior (Pinel, 2007, p 85).
Unit and multiple unit recordings are taken by passing a probe into the brain tissue. The firing rate of neurons can be determined using these processes, and electroencephalographic recording is done by placing electrodes onto the scalp, so it is "noninvasive and thus that it can be used with human subjects" (Pinel, 2007, p85).
Pharmacological methods are non-invasive and can, therefore, be used to study the human brain. Medicines known as antagonists and agonists are given to the patient to either increase or reduce the effects of neurotransmitters. Neurotransmitters are the chemical signals sent from one cell to the next, inside the brains of all living beings. Cocaine is an agonist, because when it is in the brain it prevents the effects of dopamine and norepinephrine from being repressed; insomnia, among other issues can be the result. Botox is an antagonist, and is often used in cosmetic surgery in small does to prevent wrinkles. However, Botox is a neurotoxin and "it blocks the release of acetylcholine at neuromuscular junctions" (Pinel, 2007, p 88).
There are several types of imaging procedures which can be used to study the brain; some of these methods provide more information than others. Contrast X-rays involve injection dye into the patient to which then illuminates some areas more than others. Areas of interest can be studied because they are easily identified due to the presence of the dye. X-Ray Computed Tomography is another method of brain imaging, although the patient lies with their head in a cylinder with an x-ray beam to one side, and a detector on the other. Images of the brain can be obtained from all angles around the head (Pinel, 2007, p 89).
Magnetic Resonance Imaging is said to be more effective than tomography, because it offers a colored, three dimensional look inside the brain by sending radio waves through it. The Functional MRI is said to be the most effective of all brain imaging techniques due to higher resolution which offers a clearer picture of not only the structure of the brain, but also the activity. A PET scan or Positron Emission Tomography also provides information on neural activity, however, an injection of a foreign substance is necessary to produce the required results (Pinel, 2007, p 90).
While scientists continue to explore new ways to study the human brain, existing methods are continually being improved. Less invasive methods are always best because it permits testing in human subjects rather than animals. Will it be possible to identify the cause of neurological diseases in the near future? Perhaps, in the meantime rigorous research continues into the most fascinating and complex structure known to man; the brain.
Pinel, J. P. J. (2007). Basics of biopsychology. Boston, MA: Allyn and Bacon.