It's the most mysterious and little-understood organ in the entire body: the brain. It's the source of our thoughts, our emotions and our memories. It monitors everything that happens inside our bodies, and it keeps the heart beating, the blood flowing and the lungs working without any conscious effort on our part. Also, it's responsible for whatever conscious efforts we do make. It's the original supercomputer.
When a developing fetus is only four weeks old, brain cells form at a rate of a quarter-million per minute [source: PBS]. Eventually, billions of neurons will interact and form trillions of connections. Without a brain to control the body, life wouldn't even be possible.
Due to its importance, you might think the brain would be a little more forthcoming about its design and function. Fortunately, the human brain also provides us with the remarkable ability and ingenuity to study the human brain, a skill in which brains of other life forms decidedly come up short. The study of the brain has yielded remarkable findings, and advances in brain research have created a better understanding of the way we function and life itself.
So how does science study the brain? Keep reading, brainiac, and you'll find out.
5: CT Scans
The rise of advanced medical imaging technologies has been a major breakthrough for brain researchers and a major setback for claustrophobics. Many of these scanning techniques have their origins in the 1970s, and it was during this decade that computerized axial tomography (also known as CAT, or CT) scans were developed.
Patients undergoing CT scans recline on a narrow bed, which is fed into a large doughnut-shaped tube that rotates around the patient's body. The CT scan machine forms a multitude of X-ray images from all different angles (hence the near-total enclosure of the patient). These X-ray images are used to produce cross-sectional images of bone and tissue. While an X-ray gives a single image of a bone fracture, for instance, CT scans provide researchers and doctors with multilayered, 3-D images.
So how does this work in the brain? Researchers inject a patient with an iodine-based substance that blocks X-ray imaging. Then, they follow its course through the brain, locating blockages, lesions or other damage. CT scans have also helped detect abnormalities in the brains of people with psychological disorders, such as schizophrenia.
While CT scans are useful in examining the structure of the brain, researchers developed a different imaging process that uses a magnetic field to provide an even more detailed look at the human brain, which we'll discuss next.
4: MRI Scans
While X-ray technology, ultrasound and CT scans allow for a look inside the body without actually having to cut into someone, none offers the detailed examination of magnetic resonance imaging (MRI). Using radio frequency pulses and a strong magnetic field, researchers' study of computerized MR images of the brain has allowed for great advances in brain research.
Interestingly, the brain's capacity to perform different tasks isn't set in stone. A study using MRI technology looked at the brains of dyslexic students before and after a yearlong specialized tutoring program. When they were done with the program, parts of the students' brains associated with reading showed more activity than had been the case before the start of the program [source: Rubenstein]. That means that practicing a certain task can actually improve brain activity in the area that performs the task.
MRI has been useful in other studies, as well. For example, MR imaging of identical and fraternal twins (along with unrelated individuals) helped researchers discover a link between intelligence and the amount of gray matter (brain cells) in the frontal lobe [source: Wade].
Another study -- conducted by the University of Montreal -- used MRI to study meditation's effect on pain as measured by brain activity. Researchers found that people who meditate are aware of pain. However, the parts of their brains that process and interpret that pain are less active than those of people who don't meditate [source: HealthDay News].
While MRI and other imaging technologies have greatly advanced brain research, scientists needed a way to examine the metabolic functioning of the brain. For that, researchers developed another brain-imaging technique, which we'll discuss next.
3: PET Scans
Positron emission tomography (PET) scans allow us to see the brain's metabolic functioning at a cellular level. This is done by injecting a subject with a safe dose of radioactive material. Subjects undergoing a PET scan will draw more blood -- and with it, radioactive material -- into parts of the brain that are being activated through a test or activity, such as reading aloud or recalling remembered information. A scanner connected to a computer detects the energy that the radioactive chemical gives off. It then processes the information into 3-D images. These images yield information about the flow of blood, oxygen and glucose through tissues, enabling doctors and researchers to detect tissues and organs that aren't functioning correctly.
By analyzing the amount of glucose processed in each region of the brain, researchers have shown they can use PET scans to predict (with a high degree of accuracy) the likelihood that someone experiencing small memory lapses will later develop Alzheimer's disease [source: University of California - Los Angeles].
PET scans also help detect the metabolic imbalances in the brain that are responsible for epilepsy and nervous system disorders. They help doctors discover strokes and transient ischemic attacks (TIAs, or "mini-strokes"), as well.
Furthermore, PET scans can help doctors differentiate between benign and malignant brain tumors. They're also used to determine exactly in which part of the brain seizures originate.
While PET, MRI and CT scans are noninvasive procedures, sometimes a researcher needs an approach that's quite invasive, and literally shocking. More about that next.
2: Intra-cranial Electrophysiology
Research of human behavior, learning processes and brain functions has long gone hand-in-hand with research of these same operations in mice and primates. This is due to the genetic similarity between the species. However, some functions of the human brain are unique to humans, such as formal language.
As is often the case in brain research, a study intended to glean information about one function of the brain often yields unexpected data about another function.
One such recent study involved doctors implanting electrodes onto the brains of epilepsy patients. The goal was to determine which parts of the brain could be removed to treat epilepsy while leaving all other functions intact. This procedure is known as intra-cranial electrophysiology. Once doctors implanted the electrodes, patients were instructed to sound out silently a series of words as they read them from a screen. Doctors monitored the path and duration of electrical impulses through the brain while they performed the task. In the portion of the brain responsible for language (known as Broca's area), the silent reading task set off an exact sequence of events without deviation.
Using intra-cranial electrophysiology, epilepsy researchers discovered that word identification takes around 200 milliseconds. Next, they saw that composing the word (saying it silently to oneself) takes 320 milliseconds. Gathering the information to create the exact sounds needed to form the word requires around 450 milliseconds [source: Harmon].
In the next section, we'll learn how science is studying the question that we've all probably asked ourselves: "Why am I smarter than everyone else?"
1: Intelligence Studies
Psychologists, educators, philosophers and neuroscientists have long been at odds over the issue of intelligence. Is there a single, quantitative, general intelligence, such as can be measured using an IQ test? Or are there multiple forms and types of intelligence? Either way, which parts of the brain are responsible for intelligence?
Technology is now allowing us to answer some of these highly debated questions. Using various imaging techniques, researchers in 2007 located "stations" interspersed along the path that information travels in the brain. They believe that intelligence is linked to how well (and how quickly) information passes through the billions of networks between brain cells. They've learned that some of the more important stations that seem to be linked to information processing involve attention, memory and language [source: University of California - Irvine].
This seems to indicate that general intelligence isn't specific to any one part of the brain. Rather, the brain's ability to use different information-processing functions -- and tie them together using strong connections between these regions -- seems to determine how smart we are [source: California Institute of Technology].
For lots more information about how science is studying the brain, check out the next page.
Lots More Information
- Body Works: Brain Quiz
- Fact or Fiction: Brain Myths Quiz
- Nervous System Pictures
- 10 Amazing Advancements in Neuroscience
- Cognitive Neuroscience Puzzles
- California Institute of Technology. "Brain System Behind General Intelligence Discovered." ScienceDaily. Feb. 23, 2010. (Dec. 1, 2010) http://www.sciencedaily.com/releases/2010/02/100222161843.htm
- Clark, Laura. "'Baby brain' is a myth - women's intelligence increases during motherhood, claims study." Daily Mail. Feb. 8, 2009. (Dec. 1, 2010) http://www.dailymail.co.uk/news/article-1138954/Baby-brain-myth--womens-intelligence-increases-motherhood-claims-study.html
- Cleveland Clinic. "PET Scan." 2010. (Dec. 1, 2010) http://my.clevelandclinic.org/services/pet_scan/hic_pet_scan.aspx
- Harmon, Katherine. "Rare Procedure Pinpoints the Location, Speed and Sequence of the Brain's Language Processes." Scientific American. Oct. 16, 2009. (Dec. 1, 2010) http://www.scientificamerican.com/article.cfm?id=language-process-speed-location
- HealthDay News. "Zen Meditation Can Help Bring Pain Under Control." Dec. 10, 2010. (Dec. 10, 2010) http://www.businessweek.com/lifestyle/content/healthday/647215.html
- Mayo Foundation for Medical Education and Research. "CT Scan." Jan. 12, 2010. (Dec. 1, 2010) http://www.mayoclinic.com/health/ct-scan/MY00309
- PBS. "Scanning the Brain." (Dec. 1, 2010) http://www.pbs.org/wnet/brain/scanning/pet.html
- PBS. "The Secret Life of the Brain." 2001. (Dec. 1, 2010) http://www.pbs.org/wnet/brain/
- Pines, Maya. "New Imaging Techniques that Show the Brain at Work: Brain Scans That Spy on the Senses." Howard Hughes Medical Institute. 2008. (Dec. 1, 2010) http://www.hhmi.org/senses/e110.html
- Rockefeller University Press. "T Cell Protein Boosts Learning." ScienceDaily. May 4, 2010. (Dec. 1, 2010) http://www.sciencedaily.com/releases/2010/05/100503135428.htm
- Rubenstein, Grace. "Brain Imagery Supports the Idea of Diverse Intelligences." Edutopia. April 2009. (Dec. 1, 2010) http://www.edutopia.org/multiple-intelligences-brain-research
- MedicineNet. "Magnetic Resonance Imaging (MRI Scan)." April 5, 2007. (Dec. 1, 2010) http://www.medicinenet.com/mri_scan/article.htm
- University of California - Berkeley. "Our Brains Are Wired So We Can Better Hear Ourselves Speak." ScienceDaily. Dec. 9, 2010 (Dec. 10, 2010) http://www.sciencedaily.com/releases/2010/12/101209101515.htm
- University of California - Irvine. "Brain Network Related To Intelligence Identified." ScienceDaily. Sept. 19, 2007. (Dec. 1, 2010) http://www.sciencedaily.com/releases/2007/09/070911092117.htm
- University Of California - Los Angeles. "Brain Pet Scan Predicts If Memory Lapses Will Progress Into Dementia, Detects Alzheimer's Disease At Earliest Stage, UCLA-Led Study Finds." ScienceDaily. Nov. 23, 2001. (Dec. 1, 2010) http://www.sciencedaily.com/releases/2001/11/011120054932.htm
- Wade, Nicholas. "Study Finds Genetic Link Between Intelligence and Size of Some Regions of the Brain." New York Times. Nov. 5, 2001. (Dec. 1, 2010) http://www.loni.ucla.edu/~thompson/MEDIA/NN/nyt.html
- Yale University. "Fewer synapses, more efficient learning: Molecular glue wires the brain." ScienceDaily. Dec. 9, 2010. (Dec. 10, 2010)http://www.sciencedaily.com/releases/2010/12/101208125622.htm