FoundationalConceptsNeuroscience

a more macroscopic level—what is called gross anatomy—the two
hemispheres of the human cerebral cortex appear roughly identical.
However, differences in function between the two sides of the brain
(lateralization of function) are revealed by certain methods of study.
Anosognosia (see Chapter 16) illustrates the concept of lateral-
ization of cerebral cortical function: this syndrome is more often
associated with lesions to the right cerebral hemisphere than with
damage to the left cerebral hemisphere. The perception of faces, too, is
known to differ in the involvement of the right and left hemispheres.
Prosopagnosia, for example (see Chapter 14), is more often associated
with right- than with left-hemisphere lesions.
The classic function associated with hemispheric specialization
is language—the capacity to communicate using signs, sounds, and
gestures that have understood meanings. Language is one of the most
elaborate and sophisticated aspects of human behavior, far different
from anything known to occur in other animals. Consider the three
words: I, know, you. Now consider the sentence: “I know.” And now:
“I know you know.” And now: “I know you know I know.” And now:
“IT know you know I know you know.” Using only these three words,
we can continue to build sentences of unending complexity, where
each addition changes the meaning of the statement in subtle but
significant ways. Language is more than just word meanings (seman-
tics). There are also rules (syntax) that determine the construction of
meaningful phrases and sentences. We may take it for granted, but re-
ally, it’s an amazing feat!