Re: How do scienetists know how the brain works and what it functions?

Dear Marisa,

Fantastic question!  This is something that has interested people for at 
least 5,000 years.

I will give you a brief answer to your question but I highly recommend that 
you look at the following web sites maintained by Dr. Eric Chudler, who is 
on the faculty of the University of Washington:

The home page, called "Neuroscience for Kids":
 http://faculty.was
hington.edu/chudler/neurok.html


A description of the history of neuroscience research:
 http://faculty.washi
ngton.edu/chudler/hist.html


A description of the techniques used by neuroscientists:
 http://faculty.w
ashington.edu/chudler/chmethod.html


The oldest known description of the brain and of brain injury was recorded 
by an Egyptian physician, possibly named Imhotep.  It was recorded on 
something called a papyrus.  A description of the papyrus can be found 
here:
 http://faculty.washi
ngton.edu/chudler/papy.html



There are several techniques that neuroscientists use to study the brain 
and its functions.  First, you are correct that some information has been 
gained by studying the brains of people who have died.  This method has 
been used for centuries and is still used today.  For example, the brains 
of people who had Alzheimer's disease are studied in an effort to identify 
how the disease damages the brain.  This information, in turn, may identify 
regions (or chemicals) of the brain that are important for memory.  (One of 
the characteristics of a person who has Alzheimer's disease is memory 
loss.)  Similarly, the brain of a person who displayed distinct behavioral 
changes (for example, they become aggressive) after injury to his/her brain 
is sometimes studied after the person dies in an attempt to identify the 
parts of the brain that were damaged and, thereby, correlate damage to 
certain brain regions with certain behaviors.

Some neuroscientists "lesion" (destroy) a part of the brain of a laboratory 
animal (such as a mouse or rat) and then determine what effect the lesion 
has on a particular behavior.  For example, there are researchers who use 
this technique to identify the parts of the brain that are important for 
learning to fear something.  This type of research has shown that a region 
of the brain called the amygdala plays an important role in fear.  It is 
believed that the amygdala may play an important role in fear in humans.  
This brings up the important point that much of the information that has 
been gained from the study of the function of the brain in laboratory 
animals has proven to also describe the function of the human brain.

Another technique that some investigators use is called electrical 
stimulation.  In these studies, an electrical current is applied to brain 
and the effects on behavior or on the activity of a different brain region 
is determined.

As is true for other areas of research in the biological sciences, 
neuroscientists are using the tools of genetic engineering to determine the 
function of a variety of molecules in the brain.

Finally, during the last 20 years scientists have been able to "image" (to 
produce pictures of) the brain of living people.  This is an extremely 
exciting area of research that is providing a wealth of information about 
the brain and also proving to be a major advance in the diagnosis of a 
variety of brain disorders..  You may have heard about one or more of these 
techniques: Computed Tomography Scan (CT Scan), Positron Emission 
Tomography (PET),  Magnetic Resonance Imaging (MRI) and Functional Magnetic 
Resonance Imaging (fMRI).   For a description of the techniques used to 
image the brain see:
 http://faculty.wash
ington.edu/chudler/image.html


I hope that I have stimulated your interest enough to read more about the 
neurosciences.  Keep asking questions! Neuroscience research is full 
of opportunities for questioning minds.