Survey of Modern Psychology

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Survey of Modern Psychology

• The Brain

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We will discuss

• The parts of the brain and what they do
• Neurotransmitters
• The effects of various drugs on the brain and
  neurotransmitters

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Some general notes about the brain

• Bilaterally symmetrical along the longitudinal
  fissure
• The left and right side communicate via the
  corpus callosum
• Contra lateral control the left side of the
  brain controls the right side of the body and
  vice versa

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The parts of the brain

• Going from the back of the brain towards the
  front, functions are more advanced
• Hindbrain
• Midbrain
• Forebrain

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Hindbrain
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Hindbrain

• Cerebellum
• Balance
• Damage (permanent or chemical) causes a wide
  staggering gait
• Performance and timing of skilled movements
• Damage here causes tremors during movement and an
  inability to perform rapidly alternating
  movements
• Ex. This would interfere with a skill such as
  typing
• Pons
• Regulating the brains level of attentiveness
• Initiating sleep and dreaming
• Integrates movements of and sensations from the
  facial muscles, eyes, tongue, and ears
• Medulla
• Controls basic biological functions
• Cardiovascular and respiratory systems
• Reflexes (e.g. coughing, swallowing, sneezing)
• Maintains balance by controlling head orientation
  and limb positions with respect to gravity)

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Midbrain (Mesencephalon)
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Midbrain (Mesencephalon)

• Includes the Tectum and Tegmentum
• Tracking moving stimuli (visual and auditory)
• Controls eye movements
• Coordinates simple movements (controlled by the
  hindbrain) to form more complicated wholes
• Damage here makes the organism unable to perform
  purposeful behaviors
• E.g., an animal can move and chew, but will not
  initiate a search for food when it is starving

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Forebrain
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Forebrain

• Parts
• Cerebral cortex
• Limbic system
• Thalamus
• Hypothalamus

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Forebrain

• Thalamus
• Receives sensory information and conveys it to
  the relevant structures
• E.g., vision and other senses, balancing
  information for movement
• Hypothalamus
• Controls the autonomic nervous system, endocrine
  system, and major biological drives
• Basal ganglia
• Control of movement
• Damage/degeneration here causes Parkinsons
  disease
• Weakness, tremors, rigidity of limbs, poor
  balance, difficulty in initiating movements
• Includes the hippocampus and amygdala
• Learning
• Memory
• Storing new information into long term memory
• Some regions are involved in emotions feeling
  and expressing emotion, emotional memories, and
  recognition of signs of other peoples emotions
• Stimulation generally produces feelings of
  anxiety and/or rage

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Cerebral Cortex

• Frontal lobe
• Parietal lobe
• Temporal lobe
• Occipital lobe

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Cerebral Cortex

• Frontal lobe
• Memory, strategy formation, response inhibition
• Conscious thought
• Parietal lobe
• Senses (touch, pain, temperature)
• Temporal lobe
• Hearing
• Occipital lobe
• Vision
• The frontal lobe is largely linked to personality
• Much of what we know comes from instances of
  brain damage or injury

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Phineas Gage

• In an accident in the mid 1800s, a large steel
  rod went through his head
• He survived, but friends said that there were
  major changes in his personality and was no
  longer Gage
• In general, injury to the frontal lobe results
  in
• Lack of spontaneity
• Few facial expressions and gestures
• Limited and non-fluent speech
• Strategy formation
• Lack of response inhibition
• The person does not understand rules and
  therefore has difficulty following rules

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The Hemispheres

• There is a lot of popular theory/cultural belief
  that the left and right hemispheres serve vastly
  different functions.
• In reality, both hemispheres do play some part in
  almost all areas.
• Most likely, one side is simply more effective
  and efficient in performing specific tasks.
• The division of labor is described as seen in
  right handed people.

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Visual System

• Left Hemisphere
• Letters
• Words
• Right Hemisphere
• Complex geometric patterns
• Faces

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Auditory System

• Left Hemisphere
• Language related sounds

• Right Hemisphere
• Non-language, environmental sounds
• Music

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Somatosensory System

• Left Hemisphere
• Unknown

• Right Hemisphere
• Tactile recognition of complex patterns
• E.g., Braille

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Movement

• Left Hemisphere
• Complex voluntary movement

• Right Hemisphere
• Movements in spatial patterns

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Memory

• Left Hemisphere
• Verbal memory

• Right Hemisphere
• Nonverbal memory

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Language

• Left Hemisphere
• Speech
• Reading
• Writing
• Arithmetic

• Right Hemisphere
• Prosody
• Narrative
• Inference

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Spatial Processes

• Left Hemisphere
• Unknown

• Right Hemisphere
• Geometry
• Sense of direction
• Mental rotation of shapes

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Final Notes on Hemispheres
The left and right hemispheres are joined by the
corpus callosum. In some severe cases of
epilepsy, surgery is performed to cut the corpus
callosum. 1981 the Nobel Prize was given to
Roger Sperry for his research on split brains A
participant was prevented from seeing the object
and given a pencil in their left hand The nerve
impulse therefore reached the right hemisphere,
but not the left The participant could generally
demonstrate what the pencil should be used for
with motions, but could not name the object They
could only name the object if it was placed in
the right hand. When shown a stimulus is
shown on the right side (processed by the left
hemisphere) such as words, it is processed faster
than if the same was shown on the left side. The
right hemisphere needs to send the image to the
left side for processing.
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Brain Damage

• Apraxia
• Disturbances in movement
• Lesions in the frontal lobe disconnect in
  primary and nonprimary motor areas
• Disturbances in initiation or organization of
  voluntary actions
• Ex. Unable to wave
• Ex. When trying to bake, a person might try to
  repeatedly break the same egg, or put a measuring
  spoon in a bowl as well as the ingredient

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Brain Damage

• Agnosia
• Inability to identify familiar objects using a
  particular sense
• Visual agnosia able to identify a car key by
  touch, but not by appearance
• Able to recognize parts but not a whole
• Prosopognosia inability to identify faces
• This might be the inability to recognize a face
  as a face

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Brain Damage

• Aphasia
• Disturbances in language
• Caused by damage by lesions, usually in the left
  hemisphere
• Nonfluent aphasia
• Inability to produce speech, but comprehending
  what is said
• Fluent aphasia
• Inability to comprehend what is said
• Speech is made of filler words, with no
  information
• People who can hear sometimes learn Sign Language
  to communicate
• HOWEVER
• Deaf people who suffer the same brain damage
  experience the same difficulties in communication
  as hearing people with aphasia

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Neurons

• Parts of a neuron
• Dendrites
• Receive impulses from other neurons
• Cell body
• Axon
• Synapse (the space between cells)
• Communication occurs across synapses via
  neurotransmitters
• Neurotransmitters are usually ejected, brought
  back into axons, and then reused
• Lock and key model the transmitter will only
  have an effect if it fits into the receptor
  molecules

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Neurotransmitters

• The ones we will discuss are
• Dopamine
• Serotonin
• Norepinephrine
• Acetylcholine
• GABA
• Glutamate
• Endorphins

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Dopamine

• Normal function
• Produces sensations of pleasure and reward
• Used by the central nervous system (CNS) neurons
  involved in voluntary movement
• Problems associated with imbalance
• Schizophrenia
• Parkinsons disease
• Substances that affect the action of this
  neurotransmitter
• Cocaine
• Amphetamine
• Alcohol

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Serotonin

• Normal function
• Regulates sleep and dreaming, mood, pain,
  aggression, appetite, and sexual behavior
• Problems associated with imbalance
• Depression
• Some anxiety disorders
• Obsessive compulsive disorder
• Substances that affect the action of this
  neurotransmitter
• Hallucinogenics

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Norepinephrine

• Normal function
• Used by neurons in the automatic nervous system
  and by neurons in almost every region of the
  brain
• Controls heart rate, sleep, stress, sexual
  responsiveness, vigilance, and appetite
• Problems associated with imbalance
• High blood pressure
• Depression
• Substances that affect the action of this
  neurotransmitter
• Tricyclic antidepressants
• Beta blockers

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Acetylcholine

• Normal function
• The primary neurotransmitter used by neurons
  carrying messages form the CNS
• Involved in some kinds of learning and memory
• Problems associated with imbalance
• Some muscular disorders
• Alzheimers disease
• Substances that affect the action of this
  neurotransmitter
• Nicotine
• Black widow spider venom
• Botulism toxin

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GABA

• Normal function
• The most prevalent inhibitory neurotransmitter in
  neurons of the CNS
• Problems associated with imbalance
• Anxiety
• Epilepsy
• Substances that affect the action of this
  neurotransmitter
• Barbiturates
• Minor tranquilizers (ex. valium)
• Alcohol

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Glutamate

• Normal function
• The primary excitatory neurotransmitter in the
  CNS
• Involved in learning and memory
• Problems associated with imbalance
• Release of excessive glutamate causes brain
  damage after strokes
• Substances that affect the action of this
  neurotransmitter
• PCP (angel dust)

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Endorphins

• Normal function
• Pleasurable sensations
• Control of pain
• Problems associated with imbalance
• Lowered levels resulting from opiate addiction
• Substances that affect the action of this
  neurotransmitter
• Opiates (opium, heroin, morphine, methadone)

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Drugs

• Drugs act on synapses (the spaces between
  neurons) and affect the response to
  neurotransmitters
• Agonists facilitate effects
• Antagonists inhibit effects
• Dependence and addiction are characterized by
  tolerance and withdrawal

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Drugs

• Physical vs. psychological dependence
• Physical addiction is often defined by the
  physiological effects that happen when a person
  stops using a drug
• Psychological dependence involves the emotional
  feeling of wanting the drug either to produce
  pleasure or avoid discomfort
• Psychological addiction tends to be more
  difficult to overcome than physical addiction
• Positive reinforcement if it feels good, keep
  doing it!
• Withdrawal is the opposite of whatever the
  effects of the drug are
• (E.g., withdrawal from an opiate causes
  agitation)

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Types of Drugs and their Effects

• Opiates
• Stimulants
• Nicotine
• Alcohol and Barbiturates
• Cannabis/THC

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Opiates

• Naturally occurring opiates in the brain block
  pain
• Cause analgesia, hypothermia, sedation,
  reinforcement
• Act on GABA and dopamine
• Opiate blockers may be used to treat addiction
  (no effect, therefore no reinforcement)

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Stimulants

• Dopamine agonists
• Stimulate the release of dopamine and inhibit the
  reuptake
• Euphoric, active, and talkative
• Hallucinations, paranoia, mood disturbances,
  repetitive behavior
• Similar to schizophrenia

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Nicotine

• Dopamine and acetylcholine agonists
• Often harder to quit than hard drugs
• Withdrawal includes anxiety, restlessness,
  insomnia, inability to concentrate
• Nicotine antagonists can also reduce cocaine
  cravings

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Alcohol and Barbiturates

• Dopamine and GABA agonists
• Small doses produce mild euphoria and inhibits
  anxiety stops the punishing effects of aversive
  stimuli
• Ex. if an animal is given shocks when it performs
  a particular action, it will stop. If given
  alcohol, it will not learn and keeps performing
  the response
• Alcohol
• Withdrawal can be fatal
• Convulsions and seizures
• Chronic alcoholism can lead to Korsakoffs
  Syndrome
• This is caused by a vitamin deficiency frequent
  alcohol use can block the absorption of some
  vitamins
• Permanent anterograde amnesia (inability to form
  new memories, but still having old ones)
• Confabulation making up memories
• Can have elements of reality or be completely
  imaginary

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Cannabis/THC

• Cannabis
• Dopamine agonist
• Particularly affects the hippocampus, causing
  memory problems
• Long term use can cause inattentiveness, impaired
  memory, reduced ability to multitask