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regions, they are not nearly as well developed as hers. This raises the
fascinating question, What were they doing in LB1? In order even to
guess about this, we need to consider what the frontopolar cortex does
in people.
Paul W. Burgess, of the University College, London, and his colleagues
studied the functions of BA 10 in human volunteers whose brains were
imaged as they carried out various cognitive tasks. 19 One problem in pin-
ning down its functions is that BA 10 becomes activated during a bewil-
dering variety of circumstances, including when people recall specific
events, learn a motor routine, or make judgments. It is fickle, however,
and sometimes doesn't “light up” during these kinds of tasks. People
who have suffered accidental damage to BA 10 are poor at multitasking,
because they have difficulty carrying out plans. In a nice piece of detec-
tive work, Burgess's team analyzed a voluminous literature concerning
the functions of BA 10 and added their own findings to the mix. The part
of this area that is toward the side of the brain, they concluded, nudges
individuals to pay attention to sensory input from the outside world
and to keep an eye out for what's going to happen next (watchfulness).
Burgess suggested that a main function of BA 10 is to coordinate mental
switching between internally generated thoughts and those stimulated
by external events. In other words, this part of the brain may provide
a kind of gateway or router that helps people switch between different
mental states.
When people are not busy with other tasks, the part of BA 10 that
is closer to the midline of the brain automatically prompts internally
generated thoughts, daydreaming, or simply “zoning out.” This region
also becomes activated when people have vivid dreams accompanied
by rapid eye movements . 20 Although we sometimes chastise ourselves
when our minds wander, such a “default” mode allows us mentally to
preexperience how we might act in future situations and to ponder
anticipated pleasures and pains. Patients with damaged frontopolar cor-
tex cannot simulate future events and are therefore eternally bound to
the present. These findings from contemporary neuroscience shed light
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