Myers

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Myers PSYCHOLOGY (7th Ed)

• Chapter 2
• Neuroscience, Genetics
• and Behavior
• James A. McCubbin, PhD
• Clemson University
• Worth Publishers

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Everything psychological is simultaneously
biological!

• Your every idea, mood or urge is a biological
  happening!!!!
• Without your body, you are nobody!
• Chapter 2-Neuroscience-explains how our biology
  underlies our mental behavior processes.
• Biological Psychologists study the links between
  biological activity and psychological events.

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PHRENOLOGY

• Invented by Franz Gall in the early 1800s.
• A theory that claimed that bumps on the skull
  could reveal our mental abilities and character
  traits.
• Phrenology focused the attention that various
  regions of the brain have particular, specific
  functions.

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Neuron

• a nerve cell
• the basic building block of the nervous system
• -our bodies information system is built from 100
  billion of interconnected cells called neurons.
• -many different types of neurons, but all are
  composed in the same way.
• Glial Cells
• cells in the nervous system that support,
  nourish, and protect neurons

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Dendrites (Greek for tree)

• Are the bushy, branching extensions of a neuron
  that receive messages and conduct impulses toward
  the cell body. They receive information from
  other nerve cells and send it through the soma
  or cell body to the

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Axon

• (Greek for axle)
• the extension of a neuron, (long fiber) ending in
  branching terminal fibers, through which messages
  are sent to other neurons or to muscles or glands
  (senders). At the end of the axon are thousands
  of terminal buttons.

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Vesicles and Neurotransmitters

• The area where the axon ends, in the terminal
  buttons just before the synapse, is filled with
  small containers that look like bubbles..called
  vesicles.
• Inside the vesicles are thousands of chemical
  messengers called neurotransmitters.

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Myelin Sheath

• Myelin MY-uh-lin Sheath
• a layer of fatty cells segmentally encasing the
  fibers of many neurons (insulating the axons)
• enables vastly greater transmission speed of
  neural impulses
• Multiple Sclerosis, a disease in which the myelin
  sheath degenerates, which results in a slowing of
  communication to the muscles and loss of muscle
  control.

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Synapse SIN-aps

• (means junction point)
• The space between the axon tip of the sending
  neuron and the dendrite of the receiving neuron
• tiny gap at this junction is called the synaptic
  gap or cleft
• Neurons work by electricity. Electricity will
  not go over a space, so it stops.

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Structure of a Neuron
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Neural Communication
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Neurotransmitters

• chemical messengers that traverse the synaptic
  gaps between neurons
• when released by the sending neuron,
  neuro-transmitters travel across the synapse and
  bind to receptor sites on the receiving neuron,
  thereby influencing whether it will generate a
  neural impulse
• If the message is for arm movement, the vesicles
  only release neurotransmitters involved in the
  movement circuit.
• There are dozens of different neurotransmitters.

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Neurotransmitters
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Neurotransmitters

• Acetylcholine ah-seat-el-KO-leen (Ach)
• most common, best understood
• a neurotransmitter that, among its functions,
  triggers muscle contraction
• is involved in memory (a shortage of causes
  Alzheimers Disease)
• Endorphins en-DOR-fins
• morphine within
• natural, opiate like neurotransmitters
• linked to pain control and to pleasure

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Neurotransmitters

• Dopamine-
• Involved in the control of bodily movements,
  learning, attention, emotion.
• Shortage causes Parkinsons disease
• Excessive dopamine linked with schizophrenia
• Seratonin
• Affects mood, hunger, sleep and arousal

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Addiction the result of suppressing the brains
production of its own opiates

• If indeed the endorphins lessen pain and boost
  mood, why not flood the brain with artificial
  opiates, thereby intensifying the brains own
  feel-good chemistry? One problem is that when
  flooded with opiate drugs such as heroin and
  morphine, the brain may stop producing its own
  natural opiates. When the drug is withdrawn, the
  brain may then be deprived of any form of opiate.
  For a drug addict, the result is discomfort that
  persists until the brain resumes production of
  its natural opiates or receives more artificial
  opiates. Mood altering drugs, from alcohol to
  nicotine to heroin, share a common effect The
  trigger unpleasant, lingering aftereffects.

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Lithium

• Lithium is used to treat and prevent episodes of
  mania (frenzied, abnormally excited mood) in
  people with bipolar disorder (manic-depressive
  disorder a disease that causes episodes of
  depression, episodes of mania, and other abnormal
  moods). Lithium is in a class of medications
  called antimanic agents. It works by decreasing
  abnormal activity in the brain.
• Lithium acts on a person's central nervous system
  (brain and spinal cord). Doctors don't know
  exactly how lithium works to stabilize a person's
  mood, but it is thought to help strengthen nerve
  cell connections in brain regions that are
  involved in regulating mood, thinking and
  behavior.  
• Bipolar Disorder

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Neural Communication
Serotonin Pathways
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Neural Communication

• Neural communication refers to how the neurons
  relay messages to each other. It is referred to
  an electrochemical reaction.
• Neurons are surrounded by fluid. The fluid
  inside a neuron contains negative charged atoms,
  called ions, ( - ) from the fluid located outside
  the neuron, which has positive charged ions ().

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Ions

• The neural membrane only allows certain ions
  through the membrane.
• Positively charged sodium and potassium ions and
  negatively charged chloride ions flow back and
  forth across the cell membrane, but they do not
  cross at the same rate. The difference in the
  flow leads to a higher concentration of
  negatively charged ions inside the cell.

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Electrical and Resting Potential

• Positive ions will flow into the neuron if not
  stopped or pumped out by the membrane. This is
  called the electrical potential, which is
  measured in millivolts.
• The resting potential is the neurons usual
  charge, which is 70 millivolts.
• When the resting potential has changed enough,
  about 10mv, the membrane changes and this is
  called the action potential.

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A neuron fires an impulse, when it receives
signals from sense receptorsthe impulse is
called

• Action Potential
• a neural impulse a brief electrical charge that
  travels down an axon, each tripping the next
  (depolarization)
• generated by the movement of positively charged
  ions (atoms) in and out of channels in the axons
  membrane.
• The speed at which an action potential travels
  the axon ranges from 2 to 250 mph.

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• Refractory Period- a resting pause, when the
  neuron pumps the positively charged ions back
  outsidethen it can fire again.
• Excitatory-signal to send the message
• Inhibitory-signal to stop the message
• Threshold -the level of stimulation required to
  trigger a neural impulse
• Agonist-excite by mimicking particular
  neurotransmitters or block their reuptake.
• Antagonists-inhibit a neurotransmitters release
  or block its effect.

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All or nothing neural reaction

• The neurons reaction is an all or none
  response.
• Neurons either fire or they dont. (like a gun)
• HW Assignment How is the action potential
  neuron like flushing a toilet? or like using a
  camera?

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Neural Communication
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The Nervous System

• Nervous System
• the bodys speedy, electrochemical communication
  system
• consists of all the nerve cells of the peripheral
  and central nervous systems
• Central Nervous System (CNS)
• the brain and spinal cord
• Peripheral Nervous System (PNS)
• the sensory and motor neurons that connect the
  central nervous system (CNS) to the rest of the
  body

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The Nervous System
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Three Types of Neurons

• that carry information throughout the nervous
  system
• Sensory Neurons (Afferent)
• neurons that carry incoming information from the
  sense receptors to the brain spinal cord (CNS)
• Interneurons
• CNS neurons that internally communicate and
  intervene between the sensory inputs and motor
  outputs
• Motor Neurons (Efferent)
• carry outgoing information from the CNS to
  muscles and glands

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• The sensory motor axons carrying the PNS
  information are bundled into electrical cables
  called
• Nerves
• neural cables containing many axons
• part of the peripheral nervous system
• connect the central nervous system with muscles,
  glands, and sense organs

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The Peripheral Nervous System

• Somatic Nervous System
• the division of the peripheral nervous system
  that controls the bodys skeletal muscles,
  composed of sensory motor nerves.
• Controls our voluntary movements reflexes.

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The Nervous System

• Autonomic Nervous System
• the autonomic control system of the body
• (the peripheral nervous system)
• It regulates breathing, heartbeat digestion.
• It sometimes can be overridden by the brain.
• It is a dual system composed of

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• Sympathetic Nervous System
• division of the autonomic nervous system that
  arouses the body, mobilizing its energy in
  stressful situations, slows digestion. Raises
  blood sugar pressure, heart rate, dilates eyes.
  Gets body ready for fight or flight

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• Parasympathetic Nervous System
• division of the autonomic nervous system that
  calms the body, conserving its energy
• It decreases your heartbeat, lowers your blood
  sugar and pressure.
• These two systems work together to keep us in
  balance.

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The Nervous System
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The Nervous System
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The Nervous System

• Reflex
• a simple, automatic, inborn response to a sensory
  stimulus

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The Nervous System

• Neural Networks
• interconnected neural cells
• with experience, networks can learn, as feedback
  strengthens or inhibits connections that produce
  certain results
• computer simulations of neural networks show
  analogous learning

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Methods Used in Studying The Brain

• Accidents
• In 1848, a railroad worker named Phineas Gage was
  involved in an accident that damaged the front
  part of his brain. Gages doctor took detailed
  notes documenting the brain damage and about
  Gages behavior personality changes.
• Before the accident, Gage was a nice guy, after
  the accident he was highly emotional and
  impulsive.

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2. Lesion

• is the removal or destruction of part of the
  brain.
• a brain lesion is a naturally or experimentally
  caused destruction of brain tissue
• Frontal lobotomies

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3. Electroencephalogram (EEG)

• an amplified recording of the waves of electrical
  activity that sweep across the brains surface
• these waves are measured by electrodes placed on
  the scalp

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• CT (computed tomography) Scan
• a series of x-ray photographs taken from
  different angles and combined by computer into a
  composite representation of a slice through the
  body also called CAT scan
• It creates a 3-D image of brains structure.
  Does not show function or activity.
• PET (positron emission tomography) Scan
• a visual display of brain activity that detects
  where a radioactive form of glucose goes while
  the brain performs a given task
• MRI (magnetic resonance imaging)
• a technique that uses magnetic fields and radio
  waves to produce computer-generated images that
  distinguish among different types of soft tissue
  allows us to see structures within the brain, not
  function

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MRI Scan
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PET Scan
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The Cerebral Cortex

• Functional MRI scan shows the visual cortex
  activated as the subject looks at faces

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Three regions of the brain

• 1. the forebrain
• -most recently evolved section
• 2. the midbrain
• -contains the upper part of the brain stem
• 3. the hindbrain
• -consists of structures in top part of the spinal
  cord, most of the brain stem.

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The Hindbrain

• Brainstem
• the oldest part and central core of the brain,
  beginning where the spinal cord swells as it
  enters the skull
• responsible for automatic survival functions
• Medulla muh-DUL-uh
• base of the brainstem, attaches to spinal cord
• controls heartbeat and breathing

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The Brain

• Reticular Formation (Reticular Activating System)
• a nerve network in the brainstem that plays an
  important role in controlling arousal sleep.
• Involved in controlling muscle reflexes,
  breathing perception.

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The Brain
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The Brain

• Cerebellum sehr-uh-BELL-um
• the little brain attached to the rear of the
  brainstem
• it helps coordinate voluntary movement and balance

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The Midbrain

• A segment of the brainstem located between the
  hindbrain forebrain, containing the reticular
  formation-regulating sleep arousal.

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The Forebrain

• Thalamus THAL-uh-muss
• the brains sensory switchboard, located on top
  of the brainstem
• it directs messages to the sensory receiving
  areas in the cortex and transmits replies to the
  cerebellum and medulla

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The Forebrain

• Limbic System
• a doughnut-shaped system of neural structures at
  the border of the brainstem and cerebral
  hemispheres
• associated with emotions such as fear and
  aggression and drives such as those for food and
  sex, regulates emotion, memory motivation
• includes the hippocampus, amygdala, and
  hypothalamus.
• Amygdala ah-MIG-dah-la
• two almond-shaped neural clusters that are
  components of the limbic system and are linked to
  emotion, aggression fear

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The Forebrain

• Hypothalamus
• neural structure lying below (hypo) the thalamus
  directs several maintenance activities
• eating
• drinking
• body temperature
• helps govern the endocrine system via the
  pituitary gland
• is linked to emotion

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The Limbic System
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The Cerebrum

• Is the largest most complex part of the human
  brain. It includes the brain areas that are
  responsible for the most complex mental
  activities learning, rememebering, thinking
  consciousness itself.

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The Cerebral Cortex

• Cerebral Cortex
• Is the convoluted outer layers of the cerebrum.
  The cortex is folded bent divided into 2
  hemispheres. The hemispheres are the left
  right halves of the cerebrum.
• the intricate fabric of interconnected neural
  cells that covers the cerebral hemispheres
• the bodys ultimate control and information
  processing center

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The Cerebral Cortex

• Frontal Lobes
• involved in speaking and muscle movements and in
  making plans and judgments
• Parietal Lobes
• includes the sensory cortex, registers body
  sensations
• Occipital Lobes
• include the visual areas
• Temporal Lobes
• includes the auditory areas, processes hearing
  speech

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The Cerebral Cortex
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The Cerebral Cortex
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The Cerebral Cortex

• Motor Cortex
• area at the rear of the frontal lobes that
  controls voluntary movements
• Sensory Cortex
• area at the front of the parietal lobes that
  registers and processes body sensations

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Brain Structures and their Functions
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Visual and Auditory Cortex
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The Cerebral Cortex

• Aphasia
• impairment of language, usually caused by left
  hemisphere damage either to Brocas area
  (impairing speaking) or to Wernickes area
  (impairing understanding)
• Brocas Area
• an area of the left frontal lobe that directs the
  muscle movements involved in speech
• Wernickes Area
• an area of the left temporal lobe involved in
  language comprehension and expression

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Specialization and Integration
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Specialization and Integration

• Brain activity when hearing, seeing, and speaking
  words

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Association Areas

• More intelligent animals have increased
  uncommitted or association areas of the cortex

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Brain Reorganization

• Plasticity
• the brains capacity for modification, as evident
  in brain reorganization following damage
  (especially in children) and in experiments on
  the effects of experience on brain development

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Our Divided Brain

• Corpus Callosum
• large band of neural fibers
• connects the two brain hemispheres
• carries messages between the hemispheres

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Split Brain

• a condition in which the two hemispheres of the
  brain are isolated by cutting the connecting
  fibers (mainly those of the corpus callosum)
  between them

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The Endocrine System

• Endocrine System
• the bodys slow chemical communication system
• a set of glands that secrete hormones into the
  bloodstream

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Neural and Hormonal Systems

• Hormones
• chemical messengers, mostly those manufactured by
  the endocrine glands, that are produced in one
  tissue and affect another. They work the same as
  neurotransmitters
• Pituitary Gland
• under the influence of the hypothalamus, the
  1)pituitary regulates growth and 2)controls other
  endocrine glands, Master Gland small bean
  shaped unit, located in base of the brain

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• The Thyroid Gland
• -the pituitary gland signals the thyroid,
• its job is to control metabolism.
• -It is located inside the neck and looks like a
  bow tie.

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• Adrenal ah-DREEN-el Glands
• a pair of endocrine glands just above the kidneys
• secrete the hormones epinephrine (adrenaline) and
  norepinephrine (nonadrenaline), which help to
  arouse the body in times of stress

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• The Gonads
• are sex glands that make the sperm or eggs.
• Male sex hormones are androgen testosterone
• Female hormones is estrogen
• We have both hormones in our body