Localization of Function • 33LOCALIZATION FOR LANGUAGE
Early evidence for localization of function was provided by Paul Broca’s and Carl
Wernicke’s studies of patients whose diffi culty in producing and understanding lan-
guage could be traced to damage in different areas of the brain.
In 1861, the French neurologist Paul Broca proposed that there is an area in the
frontal lobe that is specialized for producing language. Broca based this idea on his
study of patients who had suffered strokes and who produced speech that was slow and
labored, often with jumbled sentence structure. Following is an example of the speech
of a modern patient with similar symptoms. This person is attempting to describe when
he had his stroke, which occurred when he was in a hot tub.Alright... Uh... stroke and un... I... huh tawanna guy... H... h... hot tub
and... And the... Two days when uh... Hos... uh... Huh hospital and
uh... amet... am... ambulance. (From Dick et al., 2001, p. 760)Although Broca’s patients had diffi culty expressing themselves,
they had no trouble understanding what other people were saying.
When patients died, Broca performed autopsies and determined that
one specifi c area in the brain was damaged (● Figure 2.12). This area,
in the frontal lobe, came to be called Broca’s area, and the condition
he described was called Broca’s aphasia.
In 1879, Carl Wernicke studied another group of patients, who
had damage in an area of the temporal lobe now called Wernicke’s
area. Their speech was fl uent and grammatically correct, but tended to
be incoherent. The following is a modern example of the speech of a
patient similar to those Wernicke studied:It just suddenly had a feffort and all the feffort had gone with it. It even
stepped my horn. They took them from earth you know. They make my
favorite nine to severed and now I’m a been habed by the uh stam of fort-
ment of my annulment which is now forever. (From Dick et al., 2001,
p. 761)Patients such as this not only produced meaningless speech, but were
unable to understand speech and writing. This condition was called
Wernicke’s aphasia.● FIGURE 2.11 (a)
The parahippocampal
place area is activated by
places (top row) but not
by other stimuli (bottom
row). (b) The extrastriate
body area is activated by
bodies (top), but not by
other stimuli (bottom).
(Source: L. M. Chalupa &
J. S. Werner, eds., The Visual
Neurosciences, 2-vol. set, fi gure
from pages 1179–1189, © 2003
Massachusetts Institute of
Technology, by permission of
The MIT Press.)(a)preferrednonpreferred(b)preferrednonpreferredEBAPPAWernicke’s
areaBroca’s
area
● FIGURE 2.12 Broca’s and Wernicke’s areas were
identifi ed in early research as being specialized
for language production and comprehension. (Source:
L. M. Chalupa & J. S. Werner, eds., The Visual Neurosciences,
2-vol. set, Fig. 13.14, p. 323. © 2003 Massachusetts Institute of
Technology, by permission of The MIT Press.)
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