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networks, but a poor understanding of the details. For instance,
little is known about how the synaptic weights are modified,
and even where in the brain memories are stored. These are the
challenges of twenty-first century brain research.
Now let™s turn our attention to the actual human brain, as
shown in Figs. 3-5 and 3-6. Different areas of the brain are
responsible for different tasks; however, the tissue in each of
these areas is of the same construction, an intricate maze of
interconnected neurons. The outside of the brain is called the
cerebral cortex, or gray matter from its appearance. This is
the site of the most sophisticated activity in the brain, the
densest part of the neural network interconnections. The
complexity of the cerebral cortex is the single most important
difference between the brains of humans and lower animals.
Inside the cerebral cortex is white matter, which is used to
transport neural activity from one part of the brain to another.
It appears lighter than the gray matter because its axons are
covered with the fatty myelin sheath, reducing the time for
action potentials to move between locations. An important part
of the white matter is the corpus callosum, a huge pathway that
connects the left and right halves of the brain. More about this
later.
Since the brain™s function is to connect the senses with the
muscles, it is not surprising that each location on the cerebral
cortex has one of three general duties: (1) sensory, the analysis
of signals from the five senses, (2) motor, the preparation of
signals that go to the muscles, and (3) association, the
processing needed to connect the first two. For instance, the
rearmost portion of the brain, the occipital lobe or visual cortex,
processes sensory information from the eyes. Likewise, touch
and pain are processed in the sensory cortex, a narrow vertical
Chapter 3: The Third-Person View of the Mind 33




FIGURE 3-5
The human brain. The outer layer of the human brain, the cerebral
cortex, is where the most complex processing occurs. It is divided
into many different regions, each performing a specific task.


strip on the sides of the brain. Interestingly, sensory cortex is
arranged as an upside-down body. That is, sensations from the
feet are processed at the top of the strip, sensations from the
head at the bottom, and the rest of the body at corresponding
locations in between. Motor cortex, which is the initiator of
most body movement, is contained in another narrow vertical
strip positioned alongside the sensory cortex. It has the same
The Inner Light Theory of Consciousness
34

upside-down organization; feet are controlled at the top and the
head at the bottom. Other examples of sensory and motor
regions are also labeled in Fig. 3-5. These include: Heschl™s
gyri where hearing is processed, Broca™s area that controls the
muscles of speech, and the Cerebellum, a large section at the
rear of the brain that makes movement smooth and well
coordinated instead of jerky and erratic.

Damage to the Association Areas
Brain damage to the sensory and motor regions results in
problems such as blindness and being paralyzed. However,
these deficits do not directly alter the mind; the person still
thinks, feels, and remembers the same as before the injury. But
damage to the association areas is different; it affects the mind
at its very core. The essence of what we are is changed. We
will briefly describe six examples of this.
Our first example is one of the most famous accidents in
medical history. Phineas Gage was a railroad construction
foreman in 1848 Vermont. One of his duties was to prepare
blasting charges by pushing dynamite down a hole drilled into
the rock. This was done with the aid of a tamping iron, a heavy
metal rod about 3½ feet long and 1¼ inches in diameter. On
September 13, Gage was preparing such a blasting hole when
the dynamite accidentally exploded, driving the tamping bar
completely through his head. It entered under his left cheek
bone, passed behind his left eye, exited through the top of his
head, and landed about 25 to 30 yards away.
Incredibly, Phineas Gage survived the accident and lived for
another 13 years, although much of the front part of his brain
had been destroyed. The injury did not affect his sensory or
motor abilities; he could see, hear, and move his body normally.
It also did not affect his memory or intelligence. What changed
was his personality, the way he thought about things and how
he interacted with the world. Before the accident, Gage was
regarded as well-balanced, cooperative and friendly. He was a
capable supervisor and shrewd businessman. Afterwards he
Chapter 3: The Third-Person View of the Mind 35




FIGURE 3-6
Cross-section of the human brain. Interesting regions include:
ventricles, fluid filled holes in the brain; pineal gland, incorrectly
believed to be the seat of consciousness by Descartes (Chapter 7);
thalamus, a relay station for passing signals between areas; and
substantia nigra, which is destroyed in Parkinson™s disease.
The Inner Light Theory of Consciousness
36

was impatient and obstinate. He seemed to care little about
those around him and was grossly profane. He was indecisive,
seemingly unable to settle on any of the plans he devised for the
future. According to his friends, he was no longer Gage.
Modern patients with frontal brain damage exhibit similar
problems.
The second example is also from an unfortunate affliction,
a patient identified in the medical literature only as H.M. In
1953, at the age of 27, H.M. underwent a brain operation in an
attempt to control severe epileptic seizures. This procedure
removed a region called the hippocampus, located deep within
the brain (see Fig. 3-6). Although the operation was successful
for his problem with epilepsy, it left H.M. with a bizarre mental
condition. If you met and spoke with H.M., you would probably
not notice anything out of the ordinary. However, if you then
left the room and returned five minutes later, H.M. would have
absolutely no recollection of having met you. His brain is
totally incapable of transferring current thoughts into long-term
memory. He can remember events before the operation, but
virtually nothing since. H.M. is alive today, nearly 50 years
after the procedure, but his mind is trapped forever in 1953.
Example three is also a result of surgery to manage
epilepsy, resulting in what are called split-brain patients. The
left and right halves of the brain are virtually identical in
structure, but are different in their function. For instance, the
left half of the brain controls the right side of the body, and vice
versa. Also, the left half of the brain only sees the right half of
the image from each eye, while the right half of the brain only
sees what is left of center. There are also other specializations,
such as language being a left brain function, while spatial
thinking and music perception are handled on the right side.
Usually this segmentation of brain function isn™t apparent in our
behavior because the left and right sides of the brain are in
constant communication with each other. This occurs over the
large tract of nerve fibers that runs between the left and right
halves of the brain, the corpus callosum (see Fig. 3-6).
Chapter 3: The Third-Person View of the Mind 37

Starting in the 1950's, brain surgeons began cutting the
corpus callosum in epileptic patients. This was done in an
attempt to keep the storm-like neural activity of the seizure from
spreading from one side of the brain to the other. Surprisingly,
these patients seem relatively normal after the procedure, just as
long as you don™t look too closely. Clever experiments allow
the researcher to communicate with only one-half of the brain
at a time. For instance, if you display an object to the left of
where the subject is looking, or have the subject press a button
with his left hand, you are in communication with the right half
of the brain. Likewise, when the subject writes a message with
his right hand, or when he speaks, the left half of the brain is in
charge. These tricks can be used to see what each half of the
brain is thinking, feeling, remembering, desiring, and so on.
These experiments provide strong evidence that split brain
patients have two separate minds. For instance, the two halves
of the brain can have different knowledge. If a familiar object
is placed in the left hand, the right brain will recognize it, but
the left brain won™t. They can also have different opinions.
When asked about their own self worth, the right side might
respond “good,” while the left side “inadequate.” The two sides
can also have different goals. For example, the two halves of
the brain can be given opposing tasks, resulting in the hands
fighting each other. The compelling conclusion is that splitting
the brain also splits the mind.
Our fourth example is aphasia, the difficulty in under-
standing and producing speech due to brain damage, such as
from strokes. Two regions of the brain are involved, Broca™s
area and Wernicke™s area, named after researchers in the mid
1800s who studied them. Both these areas are shown in Fig. 3-
5, and are only on the left side of the brain in most people.
Broca™s area controls the muscles used in speaking. Patients
with damage in this region speak slowly and with poor flow;
however, they know what they want to say and can comprehend
the speech of others. In short, their mind is intact; they just
have difficulty in getting out the sounds and syntax.
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Damage to Wernicke™s area is far more interesting for the
study of consciousness. These patients can no longer associate
words with their meaning. Even though they may hear
normally, they cannot understand spoken language. They have
lost their dictionary; the language they have used since
childhood is suddenly foreign and incomprehensible. Their
speech is even stranger. While it is grammatically correct and
formed into complete sentences, it is gibberish and has no
meaning. This is exactly the opposite of Broca™s aphasia.
Wernicke™s aphasia patients have no difficulty producing the
sounds and syntax, but their minds can no longer produce verbal
meaning.
The fifth example is the effect of psychoactive drugs.
These are drugs that affect mental activity in some way, such as
our moods, perceptions of events, and patterns of thinking.
Most psychoactive drugs act by altering the neurotransmitters
in the synaptic gaps, usually because the two molecules
resemble each other. This allows the drug to change the
patterns of neural activity by encouraging or discouraging the
firing of individual neurons. For instance, alcohol produces
relaxation, reduces inhibitions, and impairs judgement.
Barbiturates and diazepam (Valium) calm people and reduce
anxiety. Amphetamines and cocaine produce alertness and
euphoria. Hallucinogens, such as LSD, mescaline and PCP,
alter perception and thinking patterns. Nitrous oxide, and other
drugs, change the way we perceive pain; it still hurts, but we
don™t care. Still other drugs are successful at treating such
psychological disorders as schizophrenia, depression, and
manic-depression.
Our sixth and last example is a strange condition called
synesthesia,1 from the Greek words for “combined sensation.”
About one person in every several thousand has their senses
cross-linked in some unusual way. In the most common case,

1. “Do you see what they see?”, Brad Lemley, Discover, 20, Dec.
1999, pp 80-87. Also, search the web for many on-line references.
Chapter 3: The Third-Person View of the Mind 39

the person perceives a color whenever shown a letter or number.
For example, the letter “g” might always be seen as red, the
letter “h” as blue, the digit “7” as yellow, and so on. These
colors can be extremely vivid, and are often seen as a
transparent glow around the figure. Slightly less common,
colors can be evoked by sounds, odors, tastes, and pain. Much
less frequently there are cross-links between the other senses,
such as sound causing odor, or vision causing taste. It most
cases, people with synesthesia are normal in all other ways.
What causes synesthesia? The exact details are not known,
but it is clearly related to neural activity in one area of the brain
leaking into another area where it doesn™t belong. Imagine that
we open a person™s skull and graft a nerve tract from one
location in the brain to another. Since each location handles a
different function, we would expect to see two types of brain
activity, that are normally separate, becoming joined. One
theory is that we are all born with synesthesia, a result of
undeveloped neural pathways crisscrossing the newly formed
brain. Most of these pathways die during the first few years of
life, leaving the highly segmented brain we find in adults.
Synesthesia might be caused by some of these pathways
refusing to die, leaving a “neural leak” from one area to another.
Synesthesia may seem strange at first encounter, but it is
easily explained in terms of brain structure. In fact, all six of
the previous examples provide this same lesson: The structure
and function of the mind are totally dependent on the structure
and function of the brain. All of these examples seem bizarre
and unexplainable if the mind is taken to be an entity in itself.
But when the mind is viewed as the operation of the brain,
everything falls naturally into place, and the explanations
become straightforward and simple.

The Evidence
By definition, the third-person view of the mind is from the
outside, what is seen by an external observer. And what this
external observer sees is brain activity, incredibly complex
The Inner Light Theory of Consciousness
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patterns of action potentials moving through a neural network.
The following are undisputed scientific facts, and any theory of
the mind must be able to account for each:
First, there is an unbroken path of nerve cells running
from the senses, through the neural network of the brain,
and to the muscles. For instance, suppose a person sees
an object and proclaims: “This is an apple.” Brain
scanners and scientific instruments can monitor the
resulting neural activity from its beginning to its end.
Action potentials are generated by the eyes, pass through
the sensory, association, and motor areas of the brain,
and end up at the muscles that control speech. There is no
“hidden area” in the middle; it is an unbroken chain of
events.

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