Understanding Psychology (10th Ed)

Key Concepts
How do researchers identify 
the major parts and functions 
of the brain?
What are the major parts of 
the brain, and for what 
behaviors is each part 
responsible?
How do the two halves 
of the brain operate inter-
dependently?
How can an understanding of 
the nervous system help us 
fi nd ways to alleviate disease 
and pain?

M O D U L E 9

The Brain

The brain (shown here in cross-section) may not be much to 
look at, but it represents one of the great marvels of human 
development. Why do most scientists believe that it will be 
diffi
cult, if not impossible, to duplicate the brain’s abilities?
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80 Chapter 
3 
Neuroscience and Behavior
patterns, new techniques are now used to transform the brain’s electrical activity into 
a pictorial representation of the brain that allows more precise diagnosis of disorders 
such as epilepsy and learning disabilities. 
Functional magnetic resonance imaging (fMRI) scans provide a detailed, three-
dimensional computer-generated image of brain structures and activity by aiming a 
powerful magnetic fi eld at the body. With fMRI scanning, it is possible to produce 
vivid, detailed images of the functioning of the brain. 
Using fMRI scans, researchers are able to view features of less than a millimeter 
in size and view changes occurring in intervals of 
1
∕
10
of a second. For example, fMRI 
scans can show the operation of individual bundles of nerves by tracing the fl ow of 
blood, opening the way for improved diagnosis of ailments ranging from chronic back 
pain to nervous system disorders such as strokes, multiple sclerosis, and Alzheimer’s. 
Scans using fMRI are routinely used in planning brain surgery, because they can help 
surgeons distinguish areas of the brain involved in normal and disturbed functioning 
(Mazard et al., 2005; Quenot et al., 2005; D’Arcy et al., 2007). 
Positron emission tomography (PET) scans show biochemical activity within the 
brain at a given moment. PET scans begin with the injection of a radioactive (but 
safe) liquid into the bloodstream, which makes its way to the brain. By locating 
radiation within the brain, a computer can determine which are the more active 
regions, providing a striking picture of the brain at work. For example, PET scans 
may be used in cases of memory problems, seeking to identify the presence of brain 
tumors (Gronholm et al., 2005; McMurtray et al., 2007). 
Transcranial magnetic stimulation (TMS) is one of the newest types of scan. By 
exposing a tiny region of the brain to a strong magnetic fi eld, TMS causes a momen-
tary interruption of electrical activity. Researchers then are able to note the effects of 
this interruption on normal brain functioning. The procedure is sometimes called a