Peggy finds out about the progress being made in mapping the human brain.
Segment length: 8:44
- What technology is necessary to take a picture of the mind? How can we map the brain
- when we don't completely understand how it works?
When Lewis and Clark set out to map America, they had to find ways to observe and chart
the land around them. Today's surveyors also depend on creative ways of studying and
mapping what many consider the final frontier--the human brain. While anatomical
blueprints have existed for centuries, the new challenge lies in creating a functional
map--a chart which shows where in our brain we hear music, get a joke, or even think
about our brain.
Early scientists would secretly dissect cadavers to ponder over the three-pound mass
of gelatinous tissue that forms our brain. A better way to understand the brain is
positron emission tomography (PET). This technique relies on X-ray photography to track
cerebral blood flow. Before the test, the patient is given an injection of a
radioactive glucose analogue. Since the brain
uses glucose as fuel, neurologists can identify
neuralhot spots by seeing which areas of the brain use more glucose and are therefore
more active than other areas.
Some early functional maps were made by exposing a large area of the brain during
surgery, stimulating its surface, and simply watching what happened. A technique using
that same principle, called magnetoencephalography (you can call it MEG, unless you're
really into tongue-twisters), gives neuroscientists
a less-invasive look. Small sensors are placed all over the patient's head to detect
electromagnetic changes caused by neurons. By monitoring this energy, scientists can
measure levels of brain activity. This information is updated every millisecond,
matching a patient's active thinking speed.
Scientists sometimes collect data on a subject in a roundabout manner. For instance,the
brain uses one-quarter of all the oxygen you breathe. Neurologists can identify the
active sections of the brain by tracking oxygen-rich blood. Magnetic resonance imaging,
or MRI, is the first noninvasive, nonradioactive way to observe brain activity. An MRI
machine relies on very large magnets to track the flow of blood cells in the brain and
identify where the brain processes our thoughts, motor activities, and sensations. This
system has such good terminal resolution that it can record changes in the brain which
occur even just 50 milliseconds apart.
No single mapping technique provides complete information. Scientists combine a number
of technologies to create more comprehensive maps of the human brain. These maps provide
critical information to help neurosurgeons perform safer robotic microneurosurgery or
even help scientists identify the brain sections that hear different musical tones. As
technology advances, it's just a matter of time before a map of the human mind will be
as detailed and comprehensive as a road map.
- Why do scientists need a functional as well as an anatomical map of the brain? How
would a functional map aid in brain surgery, psychology, or sports?
- How are traditional mapping techniques used in brain mapping?
glucose analogue: a compound the body
treats as glucose which has on its structure a substituted radioactive atom permitting it to be monitored
neurologist: a doctor who specializes in the
brain, the nerves, and the nervous system, as well as the diseases affecting them
neuron the basic cellular unit of the nervous
neuroscientist a scientist focusing study on some aspect of neural or nervous system
noninvasive: a medical procedure for which
it is not necessary to enter the body to obtain diagnostic information
stimulus anything that causes a reaction.The plural of stimulus is stimuli.
the brain vs. the mind Your brain is the physical, anatomical part of your central
nervous system. Your mind is your consciousness, where you feel emotions and
tracer a substance, usually radioactive, which
is followed through a physical system to study it
- Armstrong, L., et al. (1993, July 19) Watching the brain at work. Business Week, pp.
- Asimov, I. (1987) How did we find out about the brain? New York: Walker
- Begley, S., et al. (1992, Apr 20) Mapping the brain. Newsweek, pp.
- Davidoff, J. (1993, Apr 10) Brain cells made for seeing. New Scientist,
- Goldsmith, J. (1994, May) This is your brain on Tetris. Wired, pp.
- Harding, G. (1993, Dec 11) How surgeons could navigate the brain. New Scientist,
- Posner, M.I. (1993, Oct 29) Seeing the mind. Science, pp. 673-674.
Additional sources of information
American Academy of Neurology
2221 University Ave. SE, Suite 335
Minneapolis, MN 55414
Brain Information Service
BRI Publications Office
43-367 CHS/UCLA School of Medicine
Los Angeles, CA 90024-1746
(information on general brain sciences)
Society of Neurological Surgeons
750 Washington St., Box 178
Boston, MA 02111
(call to find members in your city available for speaking)
Neurologists continue to map the brain, even though they don't know exactly how it
works. In this activity, you will map an area and then use your map as well as collected
observa-tional data to deduce the function of structures within the area.
Zotar from the planet GX-911, Galaxy Syymonia
Map, identify, and explain one Earth block.
Remember, this is your first visit to Earth from the galaxy Syymonia.
Earth signs, symbols, and languages mean nothing to you. In all your observations, you must assume
that you have no previous knowledge of the block and the humans you are
- large measuring tape
- large sheets of paper for map
- smaller sheets for observations
- a team of fellow Syymonians
- Select a fairly busy block. Make sure the block includes several
types of buildings and lots of humans walking around.
- Map the block and the streets adjacent to it. With the compass, find north and mark
it with an arrow in an upper corner on your map. Using a scale of 1 cm = 2 meters,
chart the buildings around the block, measuring accurately to represent sidewalks, vegetation, and structures.
- Establish observation posts. For approximately a half hour (in Earth time), study
and take notes that will help you answer the following questions:
Which buildings do humans enter and exit from most often?
Does only a particular type of human use a certain building? Identify them by
characteristics such as age, sex, apparel, etc.
What items do the humans carry in and out of these buildings?
Observe individual human behavior. Does it differ depending on which buildings they
Does the structure of the building itself seem be a factor in its function?
Formulate theories on the uses of the various buildings on your
- What data was most helpful? What technology would have made this mission easier?
- Which were the easiest and hardest buildings to identify? Why?
- If you, as an alien, had to choose a single symbol to identify a building, what
would it be? (And as a real-life human, did you catch yourself cheating? How?)
Invite a neurologist or neurosurgeon to visit your class to explain brain structure and
mapping. Have that person describe problems such as tumors, strokes, and injuries and
the functional trouble they produce.
Visit a radiology department at a local hospital and ask a radiologist to demonstrate
the CAT, MRI, and PET scanners. Learn how tests are performed with these machines and
what kinds of study results they produce.
Bring a variety of articles (games, books, kitchen utensils, etc.) to class and place
them in a drawer. To see what kinds of problems result when a person loses one of the
brain's important functions, blindfold a class member and have that student select an
article from the drawer. Without looking at it or showing it to the class, that person
should try to identify and describe it to the other students.
The brain houses and integrates dissimilar functions in much the same way that the
rooms in a house and its yard do for different daily activities. Draw a house with a
room plan and yard. Draw lines to connect rooms and areas with integrated functions.
(For example, food prepared in the kitchen is eaten in the dining room; fatigue from
playing in the yard is relieved by sleeping in the bedroom.) Imagine one of the rooms
being destroyed. Discuss the impact this might have on an individual or on the family.
Newton's Apple is a production of KTCA Twin Cities Public Television. Made possible by
a grant from 3M. Educational materials developed with the National Science Teachers