What is Mind?
The brain, although being the most complex structure
existing on Earth - and perhaps in the Universe - is a
well-defined object: it is a material entity located inside
the skull, which may be visualized, touched and
handled. It is composed of chemical substances,
enzymes and hormones which may be measured and
analyzed. Its architecture is characterized by neuronal
cells, pathways and synapses. Its functioning depends
on neurons, which consume oxygen, exchanging
chemical substance through their membranes, and
maintaining states of electrical polarization interrupted
by brief periods of depolarization.
But... what about the mind?
It is amazing to verify that even after several centuries
of philosophical ponderations, hard dedication to brain
research and remarkable advances in the field of
neuroscience, the concept of mind still remains
obscure, controversial and impossible to define within
the limits of our language.
One strongly held view is that the mind is an entity
distinct from the brain; this speculation has its
historical roots: the early theories, termed dualistic
hypotheses of the brain function, which stated that the
material brain can be viewed mechanistically but that
mind is some entity with different and undefined
physical character. In such theories the mind was seen
as synonymous with the soul, forming an integral part
of the prevailing religious culture. For example, René
Descartes (1596-1650) the french philosopher,
perpetuated Plato's (428-348 B.C.) mind-body dualism
philosophically separating the mind and the body (1).
He stimulated the debate "How does the non material
mind influence the brain and vice versa ?" His ideas
permeated philosophical and scientific views right up
to the present day, changing the way in which
mainstream research approached the problem of self.
Since the mind and brain were now usually viewed as
isolated entities, research into these areas was
inherently separate; biochemists concerned themselves
with objective somatic mechanisms, psychologists
wrestled with the subjective properties of the mind;
philosophers and theologians carried with them the
spirit and soul.
Mindis a definition which tries to rescue the essence of
man. The essence of a person arises from the existence
of mental functions which permit him or her to think
and to perceive, to love and to hate, to learn and to
remember, to solve problems, to communicate through
speech and writing, to create and to destroy
civilizations. These expressions are closely related with
brain functioning. Therefore, without the brain, the
mind cannot exist, without the behavioral
manifestation, the mind cannot be expressed.
Spirit and soul seem to be religious and metaphysical
interpretations of the mind. Neuroscience has
understood the brain and the mind as a result of
experimental investigation. Acceptance or rejection of
the existence of the spirit and soul depends on faith
and religious conviction, which cannot be proved or
disproved by experimental methods. It seems to be
more coherent to think that beliefs are dependent on
physiological activity of the brain and of our cultural
environment. We cannot have religious concepts if we
do not have a functioning brain (e.g., as when the brain
activity is blocked by coma or deep anesthesia) and we
cannot believe in things which we do not learn, hear, or
experience. It is not impossible to think that some
people can "learn" to believe in the existence of God,
life after death and supernatural forces because the
brain is provided with emotional centers in order to
satisfy psychological needs. I frequently ask myself: "Is
there any brain region involved with mystic-religious
experience? Could either lesions or absence of those
regions abolish religious beliefs? Or, on the contray,
could "electrical storms" (hyperstimulation of neuronal
circuits) provoked by psychotic or epileptic seizure be
acting on specific brain circuitry that processes a
possible religious feeling?"
Scientists are generally reluctant to combine
experimental work with philosophy and usually reject
consideration of possible theological implications of
their studies. However, a few studies in this field have
begun to appear. Saver & Rabin (2) found that clues to
the neural substrates of religious experience, near-
death experiences and the intake of hallucinogens may
be deduced from limbic epilepsy (the limbic system is
described as the emotional system of the brain).
Ramachandran (3) reported that patients with temporal
seizures (the temporal lobe is involved with many
complex functions including emotion and memory)
sometimes experience God and religious ectasy during
seizures and are intensely religious. Assal &
Bindschaedier (4) reported a case of religious delusion
in a 39-year-old woman who had suffered a head injury
with right temporal concussion 13 years before.
Few neuroscientists, such as the Nobel Prize recipient
Sir John Eccles, asserted that the mind is distinct from
the body, but most of them now believe that all aspects
of mind, which are often equated with consciousness,
are likely to be explained in a more materialistic way as
the behavior of neuronal cells. In the opinion of the
famous neurophysiologist José Maria Delgado (5) "it is
preferable to consider the mind as a functional entity
devoid of metaphysical or religious implications per se
and related only to the existence of a brain and to the
reception of sensory inputs".
If the brain has explained the mind, how to explain
mental events as being caused by the activity of large
sets of neural cells? Neuroscientists, timidly, have
begun to combat the idea that this question is either
purely philosophical or elusive to study experimentally
and have been approaching the problem scientifically.
They have begun to gain some understanding of
possible brain mechanisms that may underlie the most
complex process in human behavior and experience,
such as the phenomena of consciousness, attention
and thought.
Certainly, one of the most remarkable examples to
illustrate the relationship between the brain and the
consciousness are the findings which state that there
seems to be "two brains" in each head (6), that is, each
hemisphere (each half of the brain) is anatomically a
mirror image of each other, since most structures are
present in both sides and they communicate by
massive bands of fiber systems. Functionally, however,
each hemisphere has its own areas of mental
specialization, a phenomenon we call "brain
lateralization". For example, the left hemisphere is
involved in highly verbal and rational functions, while
the right hemisphere is related to artistic and spatio-
visual functions. The interconnecting fibers play an
important role in coordinating the activities of the
hemispheres; their lesion may cause the individual to
behave as if the two hemisphere were responsible for
two separate consciousnesses, as firstly noted by R.
Sperry (who was awarded the Nobel for that). In other
words, if the "bridge" between the two hemispheres is
destroyed one half of our brain cannot know what the
other is doing.
Another significant finding in neurosciences is the
correlation of mental events such as learning with
chemicals and structural changes of the nerve cells (7).
Currently, we know that in our brain new neuronal
branches growth in response to environmental and
cultural diversity, that is, to training and experience.
Each neuron seems to contribute to many behaviors
and mental activities. Modern techniques are now
beginning to reveal how the brain accomplishes the
remarkable feat of learning. Networks of artificial
neurons on conventional computers are helping to
explain the ability of the brain to process and to retain
information. Also, modern cognitive sciences, which
use a vast array of new techniques, are being able to
study objectively many components of mental process,
such as attention, awareness, visual cognition,
language, mental imagery, etc., and are being
correlated with neural activity by means of
computerized functional imaging and are now open to
scientific investigation.
Finally, we realize not only the brightness and
fascination exerted on us by human mental functions,
which is responsible for the creation and evolution of
our society, but also by the darkness and despair of
mental dysfunctions, which destroy and affect the
internal and external environments of the human being.
Also in this field, the impressive advances in
neuroscience and genetics are revealing the anatomic,
biochemical and hereditary bases of schizophrenia,
mania, affective and mood disorders, anxiety,
intellectual deficits, memory disturbances and many
other (8, 9).
In conclusion, more and more we are realizing what so
many influential philosophers and theologians of past
centuries could not understand: that the brain is
complex enough to account for the mysteries of
learning, memory, emotion, creativity, consciousness,
mystical-religious experience and madness. If we agree
to think about the mind as it were a set of mental
functions rather than a spirit, soul or immaterial
substance, it will becomes easier to get on with the
necessary empirical studies and thus substantial
progress could be made not only in the search for the
nature of man as a cognitive individual, but also in the
alleviation of mental ills and in a better understanding
of cultural and religious beliefs, which, along so many
centuries have brought great pleasures - and afflictions
- to Humankind.
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