the symbolism of language,so much so that a person with damage here
may be mute.
Other areas that are located in the left frontal lobe are concerned with
motor aspects of language—speech,writing,and signing associated with
languages for the deaf.Thus,area 44 and the nearby part of 45 together
form Broca’s speech area.Complete destruction of this area results in
a severe loss of articulate speech.However,the individual’s muscles
of speech are not paralyzed,because Broca’s area is only one source of
stimulation for the primary motor cortex (indicated by the face and
tongue),which in turn influences the muscles in the head and neck that
produce speech.Broca’s area sends and receives information from many
other parts of the cortex,and PET studies show that it also participates
in motor activities that are not necessarily associated with speaking,such
as tongue movements (Petersen et al.1988).Furthermore,it has only
recently been recognized that prefrontal cortex directly in front of
Broca’s area (indicated by arrows) has an important role in producing
utterances that require some thought,unlike tasks such as simply naming
an object.Just as Broca’s area influences motor cortex that stimulates
speech muscles,a region above it influences the shoulder,arm,and hand
muscles (on the right side of the body) that are involved in writing (Xs).
Thus,damage in this area results in agraphia,which,as noted,may also
be caused by damage to area 39.The cerebellum is the great motor coor-
dinator that sits beneath the occipital lobes.Its evolutionarily newest
part,the neocerebellum,has connections with the frontal lobe and is
active during thoughtful speech.This finding is not only recent (Petersen
and Fiez 1993),but surprising,because the cerebellum was previously
believed to have nothing to do with higher thought.
Many other parts of the brain,of course,participate in sophisticated
cognition,including various aspects of language.Figure 13.1 is thus a
gross simplification that merely illustrates nodal areas within highly
complex cortical association pathways that contribute to the perception
and production of language.It also should be stressed that,although
most language processing takes place in the left hemisphere of most
people,the right hemisphere comprehends a certain amount of language
and participates in this activity to an extent,for instance,by under-
standing and providing intonations of utterances (tone of voice,or
prosody).
Just as the major or dominant left hemisphere is well known for its
language abilities,the minor right hemisphere is traditionally regarded
as the musical part of the brain.Because recent advances in medical
imaging technology make it possible to investigate the brains of subjects
as they engage in various musical activities,the relationship between200 Dean Falk