Hello:
First let me answer your question that how different parts of the
brain are structured in terms of hierarchy and what are their
functions that influence human behavior. Than allow me to comment on
the interaction and influence of these parts of the brain on the
behavior. Finally, I will discus the most widely accepted modern
theories. Please follow the link to understand my discussion through a
diagram http://www.consciousness.arizona.edu/modernsci/course/presentations/Pres-10.html
BRIEF INTRODUCTION
Scientists have long studied the brain, but during the past 20 years,
a number of exciting scientific tools have made the study of brain
functions much easier. The technique creates images of the activities
of the brain by using the computers to compile and interpret huge
amount of information from electrical activity, magnetic waves, and
other forms of radiation.
A traditional method of studying the brain activity is the
electroencephalogram, or EEG. Other kinds of most advanced technique
are called magnetic resonance imaging or MRI. More recently, a type of
MRI has been developed that allows researchers not only to image the
anatomy of the brain but also to measure the activity of the specific
parts of the brain.
STRUCTURE AND FUNCTIONS OF THE BRAIN
The most convenient classification divides the brain into three major
parts: The hindbrain, the midbrain, and the forebrain. The hindbrain
and midbrain are associated with housekeeping chores and reflexes
while the forebrain is known to control cognition, motivation, emotion
and action.
The hindbrain is the lowest part of the brain, located near the base
of the skull. Its primary responsibility is to perform routine,
“housekeeping” functions that keep the body working properly. The
hindbrain has three principal parts: the medulla, the pons, and the
cerebellum.
The medulla is a swelling at the top of the spinal cord, where the
cord enters the brain. It controls breathing and a variety of
reflexes, including those that enable us to maintain an upright
posture.
The pons is located just above medulla and is concerned with balance,
hearing, and some parasympathetic functions.
The cerebellum consists of two rounded structures located near the
rear of the pons. It has been known that the cerebellum plays a key
role in the coordination of complex muscle movements, but it has
become clear in recent years that it also plays an important role in
types of learning and memory that involve coordinated sequence of
information (Andreason, 1999: Woodruff-Pak, 1999).
The midbrain is a small area at the top of the hindbrain that serves
primarily as a center of several postural reflexes, particularly those
associated with the senses. Foe example, the automatic movement of the
eyes to keep them fixed on an object as the head moves and the
reflexive movement of the head to better orient the ears to a sound
are both controlled in the midbrain.
The forebrain is the most interesting part of the brain. Structurally,
the forebrain consists of two distinct areas. One area, which contains
the thalamus, hypothalamus, and most of the limbic system, rests at
the top of the hindbrain and midbrain. The other area, made up
primarily of the cerebral cortex, sits over the lower parts of the
brain like the fat cap of an acron covering its kernel.
The thalamus is a switching station for messages going to and fro from
the brain. It also plays an important role in the filtering and
preliminary processing of sensory information.
The hypothalamus is a small, but vitally important, part of the brain.
It lies underneath the thalamus, just in front of the midbrain. The
hypothalamus is intimately involved in our motives and emotions:
eating, drinking, sexual motivation, pleasure, anger and fear. It also
plays a key role in regulating body temperature, sleep, endocrine
gland activity, and resistance to disease; controlling glandular
secretions of the stomach and intestines: and maintaining the normal
pace and rhythm of such body functions as blood pressure and heartbeat
(Brooks, 1988). Thus the hypothalamus is the brain center most
directly linked to the functions of the nervous system. The
hypothalamus is also involved with aggression. It also appears to
contain specific pleasure centers. The hypothalamus plays its role in
the emotional arousal by working in close harmony with the limbic
system.
The limbic system is composed of amygdale, hippocampus, septal area,
and cingulated cortex, that works with the hypothalamus in emotional
aroudal.
The amygdala, a close neighbor to the hypothalamus, appears to play a
part in the emotions of fear and rage. Because the amygdala is
involved in the emotions, it plays a key role in the formation of
memories about emotionally charged events (Kandel, 1999).
The hippocampus is not only important in the regulation of emotion,
but it also is involved in the formation of new memories. The
hippocampus is believed to “tie together” the elements of memories
(their sights, sounds, meaning, etc.) that are stored in various parts
of the cerebral cortex (Nadel & Jacobs, 1998).
Along with the septal area and the cingulated cortex, the hippocampus
also brings important cognitive elements into emotion.
The largest structure in the forebrain is called the cerebral cortex.
Cerebral Cortex is associated with sensory, cognitive and motor
functions. It is also involved in conscious experience, voluntary
actions, language, and intelligence---many of the things that make us
human (Gazzaniga, 2000). The cerebral cortex is composed of four
sections, or lobes.
Frontal Lobes: It occupies the part of the skull behind our forehead
and extends back to the middle of the top of your head. The frontal
cortex has a variety of functions, not all of which are understood.
The frontal lobes play an important role in thinking, memory, and
organizing our behavior, and predicting the consequences of our
actions (Kimberg, Esposito & Farah, 1998; Schachter, 1999). It also
contains a Broca’s area which plays a very specific role in our
ability to speak language. In addition frontal lobes are believed to
play a role in the inhibition of socially inappropriate behavior.
Parietal Lobes: These lobes are located just behind the frontal lobes
at the top of the skull. The strip of the parietal cortex running
parallel to the motor area of the frontal lobes is termed the
somatosensory area. This area is important in the sense of touch and
the other body senses that tell us, among other things, where our
hands and feet are and what they are doing.
Temporal lobes: As suggested by their name, the temporal lobes extend
backward from the area of the temples, occupying the middle area at
the base of the brain beneath the frontal and parietal lobes. The
temporal lobes contain the auditory areas. It also plays an essential
role in the understanding of spoken language.
Occipital lobes: The occipital lobes are located at the base of the
back of the head. The most important part of the occipital lobes is
the visual area. The visual area plays an essential role in the
processing of sensory information from the eyes.
Although the cerebral cortex is composed of four lobes but it is also
divided into two hemispheres which are known as cerebral hemispheres.
The two hemispheres are linked by the corpus callosum. Both of the
hemispheres coordinate with each other. Many of the functions of the
cerebral cortex are shared by both hemispheres. However, the two
hemispheres work together in a way that is different from what we
might think. Input from the senses of vision and touch, for example
goes to the opposite hemispheres. Stimulation of the skin on the left
hand goes to the right cerebral hemisphere and vice versa. Wiggling of
the toes on our left foot is controlled by the right hemisphere.
The right hemisphere plays a greater role in both the expression and
perception of the emotions. It is also essential in understanding the
emotions expressed by others (Blonder, Bowers, & Heilman, 1991).
The left hemisphere plays a grater part in processing positive
emotions. On the other hand the right hemisphere is more involved with
negative emotions (Davidson, Ekman, Saron, Senulis, & Friesen, 1990).
THE BRAIN IS AN INTERACTING SYSTEM
Even though it is convenient to think of the brain as being divided in
to many separate parts, you should know that the parts commonly work
together in intellectual and emotional functioning. Consider, for
example, your reaction in the following situation. You are waiting at
the bus stop late at night. A poorly dressed man approaches smelling
of alcohol. He asks if you can spare 5 dollars. In his pocket, you see
the outline of what might be a gun. Your reaction to this scene would
involve many parts of your brain working together. Parts of your
celebral cortex evaluate the possible threat to you and the
alternative courses of action open to you. Your limbic is involved in
a process of emotional arousal. If you fight, run, or reach into your
pocket to hand over the money the motor areas of your cortex will work
with your hindbrain and midbrain to coordinate the muscular movements
involved. The many parts of the brain work together.
Sometimes the many parts of the brain interact because one part of
the brain sends a message to another part, which then sends it onto a
third part of the brain, and so on more often, however, several parts
of the brain process different kinds of related information at the
same time. To use computer language, the brain often uses “parallel”
processing (handling different information at the same time) rather
then “serial” processing ( handling one kind of information at a time)
(Rumelhart & McClelland, 1986). The brain’s amazing capacity for
parallel processing magnifies its ability to use its hundred billion
neurons and there trillions of connections to produce our complex
actions, emotions, and thoughts.
THEORIES
Nature of Conscious Experience
Structuralism
Wundt and Titchener studied the elements of consciousness using the
method of looking inward at one’s own conscious experiences, called
introspection. Wundt and Totchener trained themselves to observe the
contents of their own minds as accurately and unemotionally as
possible in an attempt to isolate the basic elements of the mind. The
process of determining the structure of the mind through controlled
introspection is known as Structuralism.
Gestalt psychology
The school of thought based on the belief that human consciousness
cannot be broken down into its elements. Their approach was founded on
the concept of the gestalt, or whole. Max Wertheimer and other leading
gestalt Psychologists felt that human consciousness could not be
meaningfully broken down into raw elements, as the structuralists
tried to do.
Functions of the Conscious Mind
Functionalists
William James and some scientists emphasized the useful functions of
consciousness. They speculated that thinking, feeling, learning,
remembering, and other processes of human consciousness existed only
because they helped us survive as species.
Cognitive Psychology
Modern version of Functionalism, Cognitive psychology emphasizes the
importance of cognitive processes, such as perception, memory, and
thinking.
Psychometrics
This perspective of psychology was founded by Alfred Binet that
focuses on the measurement of mental functions. He developed a way to
measure intelligence and used the intelligence scale in different
institutions and organizations.
Behaviorism and Social Learning Theory
Conditioning
Ivan Pavlov discovered a simple form of learning that is known as
conditioning in which an inherited reflex (salivating) comes to be
triggered by a stimulus that has nothing to do with that reflex. He
demonstrated that inherited reflexes could not be influenced
dramatically by learning experiences.
Social Learning Theory
This viewpoint by Albert Bandura states that the most important aspect
of our behavior are learned from other persons in society --- we learn
to be who we are from our family, friends , and culture.
The Nature of Unconscious Mind
One of the leading physicians of his day Sigmond Freud believed that
conscious mental processes were of trivial importance compare with the
workings of the unconscious mind. Sensation, learning, memory and
other cognitive process are of the greatest importance and the
theories of other physicians, psychologists and medical fieldsmen were
of little or no importance to Sigmond Freud.
MAJOR RESOURCES & REFERENCE
Lahey, B.B. Psychology: An Introduction, Chicago: McGraw Hill, 2001.
Sousa, A. David. How the Brain Learns, Thosand Oaks : Corwin press
Inc., 2002.
MINOR RESOURCES & REFERENCE
Woodruff-Pak, D.S. (1999). New directions for a classical paradigm:
Human eyeblink conditioning. Psychological Science, 10, 1-3
Andreason, N.C., (1999). A unitary model of schizophrenia: Bleuler’s
“fragmented phrene” as schizoencephaly. Archives of General
Psychiatry, 56, 781-787.
Kandel, E.R. (1999). Biology and the future of psychoanalysis: A new
intellectual framework for psychiatry revisited. American Journal of
psychiatry. 156, 505-524.
Nadel,L., & Jacobas, W.J. (1998). Traumatic memory is special. Current
Directions in Psychological Science, 7, 154-157.
Gazzaniga,M. (1992). Nature’s mind: the biological roots of thinking,
emotion, sexuality, language, and intelligence. Boston: Houghton
Mifflin.
Kimberg,D.Y.,Esposito,M.D.,& Farah, M.J. (1998). Cognitive functions
in the prefrontal cortex: Working memory and executive control.
Current directions in psychological Science, 6, 185-192.
Schaster,J. (1989). Why we need a program for the control of Chlamydia
trachomatics. New England journal of Medicine, 320, 802-803.
Blonder,L.X., Bowers, D., & Heilman, K.M.(1991). The role of the right
hemisphere in emotional communication. Brain, 114, 1113-1127.
Davidson, R.J., Ekman, P., Saron, C.D., Senulis, J. A., & Friesen,
W.V. (1990). Approach-withdrawal and cerebral asymmetry : Emotional
Expression and brain Psychology. Journal of Personality and Social
Psychology, 58, 330-341.
Rumelhart, D.E., & McClelland, J.L. (Eds,). (1986). Parallel
distributed processing: Explorations in the microstructure of
cognition, Vol 1: Foundations. Cambridge, MA : MIT Press.
Hope this will work. If you are unclear about anything, please
clarify. Thanks for asking.
Sincerely,
Leader-ga. |
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